Lineside Signal Aspects and Indications

Transcription

1 Supersedes Iss 1 (to correct formatting) and supersedes Lineside Signal Aspects and Indications Synopsis This document specifies the appearance of lineside signal aspects and s and the information they convey. Copyright in the Railway Group documents is owned by Rail Safety and Standards Board Limited. All rights are hereby reserved. No Railway Group document (in whole or in part) may be reproduced, stored in a retrieval system, or transmitted, in any form or means, without the prior written permission of Rail Safety and Standards Board Limited, or as expressly permitted by law. members are granted copyright licence in accordance with the Constitution Agreement relating to Rail Safety and Standards Board Limited. In circumstances where Rail Safety and Standards Board Limited has granted a particular person or organisation permission to copy extracts from Railway Group documents, Rail Safety and Standards Board Limited accepts no responsibility for, nor any liability in connection with, the use of such extracts, or any claims arising therefrom. This disclaimer applies to all forms of media in which extracts from Railway Group documents may be reproduced. Published by Copyright 2018 Rail Safety and Standards Board Limited

2 Supersedes Iss 1 (to correct formatting) and supersedes Issue Record Issue Date Comments 1 03/03/2018 This document replaces GKRT0058 issue one Lineside Signal Aspect and Indication Requirements and GKGN0658 issue one Guidance on Lineside Signal Aspect and Indication Requirements, which have been withdrawn in accordance with the strategy for Rail Industry Standards. The requirements for providing buffer stop lights are revised. The requirements for display combinations are revised to permit a PoSA aspect to be presented with a junction and a preliminary junction to be presented with a banner OFF /03/2018 This document has been reissued to correct formatting only. There are no changes to the content. This document will be updated when necessary by distribution of a complete replacement. Superseded Documents The following Railway Group documents are superseded, either in whole or in part as indicated: Superseded documents Sections superseded Date when sections are superseded GKRT0058 issue 1 Lineside Signal Aspect and Indication Requirements GKGN0658 issue 1 Guidance on Lineside Signal Aspect and Indication Requirements All 03/03/2018 All 03/03/2018 Supply The authoritative version of this document is available at Enquiries on this document can be submitted through the Customer Self-Service Portal Page 2 of 89

3 Supersedes Iss 1 (to correct formatting) and supersedes Contents Section Description Page Part 1 Purpose and Introduction Purpose Application of this document Health and safety responsibilities Structure of this document Approval and Authorisation 12 Part 2 Signal Aspects and Indications: Presentation Introduction to signal aspects and s Presenting signal aspects Maximum interruption of presented signal aspects and s Signal aspect combinations Semaphore signal arm combinations Signal aspect and route combinations Signal aspect and supplementary combinations 27 Part 3 Lineside Signal Aspects: Appearance and Meaning Stop aspects Shunting conditional stop aspect Shunt aspect Permissive aspect PoSA aspect aspect caution aspect cautionary aspects TCB unrestricted proceed aspect Distant aspects Block and non-block stop signal proceed aspects Flashing signal aspects Junction splitting distant aspects 52 Part 4 Banner Repeater Indications: Appearance and Meaning Banner repeater s Splitting banner s 58 Part 5 Route Indications: Appearance and Meaning Junction s 66 Page 3 of 89

4 Supersedes Iss 1 (to correct formatting) and supersedes 5.2 Preliminary route s Alphanumeric route s 72 Part 6 Equipment Status Indications: Appearance and Meaning Infrastructure not operated Facing points set Locally monitored LC s TPWS s Mechanical trainstop system 82 Part 7 Operating Indications: Appearance and Meaning Train dispatch system s Loading and unloading s 84 Definitions 86 References 89 Page 4 of 89

5 Supersedes Iss 1 (to correct formatting) and supersedes List of Figures Figure 1: Permitted semaphore stop and distant signal arm combinations 20 Figure 2: Permitted semaphore main and subsidiary signal arm combinations 21 Figure 3: Example of a semaphore junction signal displaying stepped arms applicable to three routes with an MA shown towards the branch (route 3) 21 Figure 4: Example of a semaphore shunting signal that displays stacked arms or discs applicable to three routes (showing left- and right-hand divergences), with an MA along siding 1 22 Figure 5: Example colour light signal aspect and junction combinations (position 2 and position 5 shown) 25 Figure 6: Example colour light signal aspect and alphanumeric route combinations 25 Figure 7: Example of a junction signal displaying a position 1 junction and alphanumeric route combination 26 Figure 8: Examples of semaphore signal aspect and route combinations 26 Figure 9: Examples of position light signal aspect and route combinations 26 Figure 10: An example of different alphanumeric route s presented with main proceed-aspects and subsidiary position light signal aspects 27 Figure 11: Example of a banner junction 27 Figure 12: Colour light signal (CLS) main stop aspect 31 Figure 13: Semaphore main stop aspect 31 Figure 14: Stop board 31 Figure 15: Reflectorised buffer beam 31 Figure 16: Position light signal (PLS) stop aspect 32 Figure 17: Miniature semaphore stop aspect 32 Figure 18: Shunting disc stop aspect 32 Figure 19: Shunting conditional stop aspect 33 Figure 20: PLS shunt aspect 35 Figure 21: Semaphore shunt aspect (disc) 35 Figure 22: Semaphore shunt aspect (upper quadrant miniature arm) 35 Page 5 of 89

6 Supersedes Iss 1 (to correct formatting) and supersedes Figure 23: Subsidiary PLS shunt aspect - CLS 35 Figure 24: Colour light permissive aspect 37 Figure 25: Semaphore permissive aspect 37 Figure 26: Subsidiary PoSA aspect 39 Figure 27: Independent PoSA aspect 39 Figure 28: CLS 3-aspect caution 40 Figure 29: Distant board 40 Figure 30: CLS 4-aspect double yellow caution 41 Figure 31: CLS 4-aspect single yellow caution 41 Figure 32: CLS green main proceed aspect 43 Figure 33: Semaphore main proceed aspect (upper quadrant) 43 Figure 34: CLS double yellow distant ON aspect 44 Figure 35: CLS single yellow distant ON aspect 44 Figure 36: Semaphore distant ON aspect 44 Figure 37: Distant board 44 Figure 38: CLS distant OFF aspect 45 Figure 39: Semaphore distant OFF aspect (upper quadrant) 45 Figure 40: Semaphore home OFF aspect (upper quadrant) 47 Figure 41: CLS single yellow home OFF aspect 47 Figure 42: CLS green home OFF aspect 47 Figure 43: Semaphore section signal OFF aspect (upper quadrant) 48 Figure 44: CLS single yellow section signal OFF aspect 48 Figure 45: CLS green section signal OFF aspect 48 Figure 46: Flashing double yellow aspect 50 Figure 47: Flashing single yellow aspect 50 Figure 48: Flashing single yellow aspect (4-aspect head) 50 Figure 49: Splitting distant straight ahead caution - right-hand junction 52 Figure 50: Splitting distant straight ahead caution - left-hand junction 52 Page 6 of 89

7 Supersedes Iss 1 (to correct formatting) and supersedes Figure 51: Splitting distant left-hand junction caution 53 Figure 52: Splitting distant right-hand junction caution 53 Figure 53: Splitting distant straight ahead unrestricted proceed-aspect right-hand junction 54 Figure 54: Splitting distant straight ahead unrestricted proceed-aspect left-hand junction 54 Figure 55: Splitting distant left-hand junction unrestricted proceed-aspect 54 Figure 56: Splitting distant right-hand junction unrestricted proceed-aspect 55 Figure 57: Examples of splitting distant signal aspects when the limit of MA is before the junction 56 Figure 58: Banner ON 57 Figure 59: Banner white-off 57 Figure 60: Banner green-off 57 Figure 61: Equal height banner-on 59 Figure 62: Left-hand offset banner-on 59 Figure 63: Right-hand offset banner-on 59 Figure 64: 2-state banner-off - left-hand equal height 59 Figure 65: 2-state banner-off - right-hand equal height 60 Figure 66: 2-state banner-off - left-hand higher speed route 60 Figure 67: 2-state banner-off - right-hand higher speed route 60 Figure 68: 2-state banner-off - left-hand lower speed route 60 Figure 69: 2-state banner-off - right-hand lower speed route 61 Figure 70: 3-state banner white-off - left-hand equal height 61 Figure 71: 3-state banner green-off - left-hand equal height 61 Figure 72: 3-state banner white-off - right-hand equal height 61 Figure 73: 3-state banner green-off - right-hand equal height 62 Figure 74: 3-state banner white-off - left-hand higher speed route 62 Figure 75: 3-state banner green-off - left-hand higher speed route 62 Figure 76: 3-state banner white-off - right-hand higher speed route 62 Figure 77: 3-state banner green-off - right-hand higher speed route 63 Page 7 of 89

8 Supersedes Iss 1 (to correct formatting) and supersedes Figure 78: 3-state banner white-off - left-hand lower speed route 63 Figure 79: 3-state banner green-off - left-hand lower speed route 63 Figure 80: 3-state banner white-off - right-hand lower speed route 64 Figure 81: 3-state banner green-off - right-hand lower speed route 64 Figure 82: Position 1 Junction indicator (JI) 66 Figure 83: Position 2 JI 66 Figure 84: Position 3 JI 67 Figure 85: Position 4 JI 67 Figure 86: Position 5 JI 67 Figure 87: Position 6 JI 68 Figure 88: The relationship between each junction and the direction of the routes at a diverging junction 69 Figure 89: Example of a position 1 or position 4 junction on the approach to a right-hand flying junction 69 Figure 90: Position 0 preliminary route (PRI) 70 Figure 91: Position 1 PRI 70 Figure 92: Position 2 PRI 70 Figure 93: Position 3 PRI 71 Figure 94: Position 4 PRI 71 Figure 95: Position 5 PRI 71 Figure 96: Position 6 PRI 71 Figure 97: 'Standard' ARI (SARI) 73 Figure 98: 'Miniature' ARI (MARI) 73 Figure 99: MARI 'X' 73 Figure 100: Infrastructure not operated 77 Figure 101: Facing points set 78 Figure 102: Facing points set using position light signal OFF display 78 Figure 103: Locally monitored LC 79 Figure 104: BU 79 Page 8 of 89

9 Supersedes Iss 1 (to correct formatting) and supersedes Figure 105: TPWS set 80 Figure 106: TPWS disarmed 81 Figure 107: Trip-cock test 82 Figure 108: OFF 83 Figure 109: CD 83 Figure 110: RA 83 Figure 111: Stop 84 Figure 112: Prepare to stop 84 Figure 113: Forwards 84 Figure 114: Reverse 85 Page 9 of 89

10 Supersedes Iss 1 (to correct formatting) and supersedes List of Tables Table 1: Information types conveyed by lineside signalling displays 16 Table 2: Permitted signal aspect and route combinations 23 Table 3: Signal aspect and supplementary display combinations 27 Table 4: Main stop aspects 31 Table 5: Shunting stop aspects 32 Table 6: Shunting conditional stop aspect 33 Table 7: Shunt aspects 35 Table 8: Permissive aspects 37 Table 9: PoSA aspects 39 Table 10: 3-aspect caution 40 Table 11: Cautionary aspects in 4-aspect signalling areas 41 Table 12: Unrestricted proceed aspect in TCB signalling areas 43 Table 13: Distant ON aspects 44 Table 14: Distant OFF aspects 45 Table 15: Home signal, Section signal, Intermediate Block home signal, and non-block stop signal OFF aspects 47 Table 16: Section signal and intermediate block home signal OFF aspects 48 Table 17: Junction flashing aspects 50 Table 18: Junction splitting distant signal aspects 52 Table 19: Banner repeater s 57 Table 20: Splitting banner repeater ON s 59 Table 21: 2-state splitting banner repeater OFF s 59 Table 22: 3-state splitting banner repeater OFF s 61 Table 23: Junction s (JI) 66 Table 24: Preliminary junction s 70 Table 25: Alphanumeric route s 73 Page 10 of 89

11 Supersedes Iss 1 (to correct formatting) and supersedes Table 26: Typical alphanumeric route s 74 Table 27: Alphanumeric s that are used for applications other than route s 75 Table 28: Locally monitored infrastructure not operated 77 Table 29: Facing points set 78 Table 30: Locally monitored LC 79 Table 31: TPWS s 80 Table 32: Mechanical trip-cock test 82 Table 33: Train dispatch system s 83 Table 34: Loading and unloading s 84 Page 11 of 89

12 Supersedes Iss 1 (to correct formatting) and supersedes Part 1 Purpose and Introduction 1.1 Purpose This document is a standard on lineside signal aspect and requirements for the GB mainline railway This document specifies the appearance of lineside signal aspects and s and the information that each is used to convey The scope of this document does not include compatibility of lineside signal aspects and s with train driving processes when an in-cab signalling system is in use. 1.2 Application of this document Compliance requirements and dates have not been specified since these will be the subject of internal procedures or contract conditions The Standards Manual and the Railway Group Standards (RGS) Code do not currently provide a formal process for deviating from a (RIS). However, a member of, having adopted a RIS and wishing to deviate from its requirements, may request a Standards Committee to provide opinions and comments on their proposed alternative to the requirement in the RIS. Requests for opinions and comments should be submitted to by to proposals.deviation@rssb.co.uk. When formulating a request, consideration should be given to the advice set out in the Guidance to applicants and members of Standards Committee on deviation applications, available from s website. 1.3 Health and safety responsibilities Users of documents published by are reminded of the need to consider their own responsibilities to ensure health and safety at work and their own duties under health and safety legislation. does not warrant that compliance with all or any documents published by is sufficient in itself to ensure safe systems of work or operation or to satisfy such responsibilities or duties. 1.4 Structure of this document This document sets out as a series of requirements that are sequentially numbered. This document also sets out the rationale for the requirement, explaining why the requirement is needed and its purpose, and where relevant, guidance to support the requirement. The rationale and the guidance are prefixed by the letter G Some subjects do not have specific requirements but the subject is addressed through guidance only and where this is the case, it is distinguished under a heading of Guidance and is prefixed by the letter G. 1.5 Approval and Authorisation The content of this document was approved by Control Command and Signalling Standards Committee on 08 June Page 12 of 89

13 Supersedes Iss 1 (to correct formatting) and supersedes This document was authorised by on 30 January Page 13 of 89

14 Supersedes Iss 1 (to correct formatting) and supersedes Part 2 Signal Aspects and Indications: Presentation 2.1 Introduction to signal aspects and s G G G G G G G G Guidance This rail industry standard sets out the requirements for lineside signal aspects and s so that they are interpretable. Providing lineside signalling assets that are interpretable is a precondition of achieving a lineside signalling system that is driveable. Users interpret lineside signal aspects and s using their competence, experience and knowledge and use the information to inform the task they are undertaking (for example, train driving or train dispatch). The relationship between the lineside signalling displays and the users is described using the defined term 'interpretability', where the contribution of the lineside signalling display is to 'be interpretable' and the contribution of the user is to 'interpret'. The specific contribution that each user brings to interpretability is dependent on the role being performed and the tasks being undertaken. If a user makes an error in interpreting a signal aspect or, and the error is not corrected, this may be a causal factor in the sequence of events leading up to a train exceeding its movement authority (MA) or other operating incident. The following types of information are presented by the signal aspects and s specified in this document. a) MA. b) Routing. c) Locally monitored infrastructure status. d) Train operating information (for example 'close doors'). The following factors support and influence the extent to which each display is interpretable: a) Display appearance. b) Display combination. c) Spatial compatibility with the track layout. d) Consistency of conveyed information. e) Concept compatibility. A proposal to implement a new type of signal aspect or, or convey an alternative type of information using an existing display should be supported by evidence that it optimises interpretability and a risk assessment that addresses the risk from misinterpretation. Display appearance: This document specifies the appearance of the lineside signal aspects and s presented on the Great Britain (GB) mainline railway and the information conveyed. A lineside signal aspect or that has an unusual appearance or a different meaning to that usually associated with a particular display is more difficult to interpret. Page 14 of 89

15 Supersedes Iss 1 (to correct formatting) and supersedes G G G G G Display combination: This document specifies the permitted combinations of lineside signalling displays covering three groups: a) Signal aspect combinations, where discrete signal aspects are presented together to convey a particular set of MA information, for example, a junction splitting distant aspect. b) Signal aspect and route combinations, where routing information is presented with the MA at a junction signal. c) Signal aspect and supplementary, where one or more additional pieces of information is presented with the MA, for example 'right away'. Spatial compatibility with the track layout can be used to convey information about the direction of the route at a diverging junction. The requirements in this document apply the following spatial compatibility principles: a) The relative horizontal position of each signal aspect or mimics the track layout (for example, the left-hand signal aspect or applies to the left-hand route). b) The relative vertical position of each signal aspect or corresponds to the relative permissible speed of each route, where a higher position indicates a higher permissible speed. Consistency of conveyed information: A lineside signalling system design where any particular display appearance is always used to convey the same information is easier to interpret than one where either a particular display appearance can have more than one meaning or the same meaning can be conveyed by different display appearances and meanings. Inconsistent signal aspects and s are sometimes used to overcome an operational constraint or a signalling system design limitation. Concept compatibility concerns the features of display appearance that help users to correctly interpret the information being conveyed. The following lineside signalling system features support concept compatibility: a) Display colour. b) Display shape. c) Display alignment. d) Flashing and steady displays. e) Alphanumeric characters. The better the concept compatibility, the easier it is to interpret the information being conveyed. Displays with good concept compatibility can be interpreted on the basis of appearance alone, whereas displays with poor concept compatibility require the user to learn their meaning in order to interpret them. Displays that have good concept compatibility in the wider social context place very little reliance on prior learning to be interpretable. For example, the colour red has concept compatibility with danger messages in the wider social context. Consequently, the colour red is used within the signalling system to convey information about the limit of MAs. Railway specific knowledge about lineside signalling systems means that most signal aspect and features support concept compatibility in the context of users and Page 15 of 89

16 Supersedes Iss 1 (to correct formatting) and supersedes G G railway operations. For example, semaphore signal arms in the horizontal position always convey restrictive information. A consistent display appearance and meaning helps users to reliably interpret the information being conveyed by each lineside signal aspect and. A more variable appearance or meaning has the potential to result in a user misinterpreting the conveyed information and misunderstanding the required action. Table 1 is a summary of the lineside signalling displays presented on the GB mainline railway and the information they convey. Requirements for particular displays and the information they convey are set out in sections 3 to 7. Signalling information type Movement authority (MA) Repeated MA Routing Repeated routing MA and routing Repeated MA and routing Locally monitored system status Operating instruction Display type Signal aspect Banner repeater Junction Alphanumeric route Preliminary route Semaphore junction signal OFF aspect Flashing signal aspect Splitting distant signal aspect Splitting banner repeater or single banner and PRI Coloured light Lit alphanumeric Coloured light Lit alphanumeric G G Table 1: Information types conveyed by lineside signalling displays In some cases, different locations apply the same display appearance to convey different information. This places a greater reliance on users to correctly interpret the information being conveyed. The lineside signalling layout driveability assessment is used to: a) Evaluate the driveability hazard precursor: poor interpretability. b) Identify what can be done to eliminate the hazard or control the risk. 2.2 Presenting signal aspects Each lineside signal shall continuously present the relevant signal aspect, except where the signal is configured with approach lighting functionality. Page 16 of 89

17 Supersedes Iss 1 (to correct formatting) and supersedes A signal shall be configured with approach lighting functionality only if both of the following criteria apply: a) The signal aspect does not contribute to the overall readability of signals on other lines. b) The relevant signal aspect is readable whenever the signal is approached by a train on the line to which it applies. G G G G G G G Rationale These requirements can be used to control the driveability hazard precursor: Poor interpretability due to poor readability. Guidance Lineside signal aspects are designed to be visible and readable whenever users need to use them to understand signal section or block section limits. The consistent pattern of signal aspects in the field of vision helps users to correctly understand their position within the overall infrastructure layout. Intermittently lit signal aspects would result in a variable appearance and make it more difficult for users to form this understanding. Approach lighting functionality should be implemented only if a signal sighting assessment confirms that the overall readability of signal aspects and s will be unaffected or improved by extinguishing a signal aspect until it is needed to convey MA information applicable to an approaching train. The following situations are examples of where approach lighting functionality can be of benefit: a) Where an isolated stop signal is provided at the end of a siding or loop, to reduce the likelihood that drivers of trains operating on the parallel running line would misread the stop aspect as applicable to their train. b) In the case of a line with a very low train frequency (for example, one train a day or less), the signalling system could be designed to extinguish complete groups of signals when the railway is not being used, to reduce power consumption. In this case, all potential users of the signalling system should be considered, and the design of the signalling control system should take account of the likelihood of signalling system failure. Where approach lighting functionality is provided, the signal aspect illuminates before a train to which it applies reaches the required readable distance (RRD) of the signal. At some locations the signalling controls include proving the signal is lit before an MA is issued for a train to approach it. Further requirements and guidance about the signal sighting assessment process, which includes requirements for assessing the RRD of a signal, are set out in RIS-0737-CCS. Page 17 of 89

18 Supersedes Iss 1 (to correct formatting) and supersedes 2.3 Maximum interruption of presented signal aspects and s The interruption of signal aspects and s that are not designed to flash shall not exceed a single interruption within one hour of a previous interruption and each interruption shall not exceed 250 ms. G G G Rationale This requirement can be used to control the following driveability hazard precursors: a) Poor readability. b) Poor interpretability. Guidance In some cases, signalling system technology incorporates a self-test function that results in a brief interruption to the generated display at defined intervals. The permitted interruption parameters are consistent with solid state interlocking systems currently applied in GB. More frequent or longer interruptions observed by users would increase their potential as a distraction or a cause of misinterpretation. 2.4 Signal aspect combinations Signal aspect combinations shall be presented only where one or more of the following apply: a) Where a specified signal aspect or, with a specific meaning, comprises a combination of displays, which are also specified separately as discrete signal aspects or s with a different meaning. b) Where a semaphore signal incorporates multiple signal arms as specified in this document. c) At a co-acting signal. G G G Rationale This requirement is relevant to militating against the driveability hazard precursor: Poor interpretability Guidance Signal aspect combinations convey logical sets of information. Users presented with signal aspect combinations that convey conflicting or illogical MA information would be faced with having to decide which information takes precedence. The signal aspect combinations set out in this document are consistent with the displays presented by: a) Colour light subsidiary signals. b) Colour light splitting distant signals. c) Semaphore main stop and distant signals. Page 18 of 89

19 Supersedes Iss 1 (to correct formatting) and supersedes G d) Semaphore junction signals. e) Semaphore subsidiary signals. f) Co-acting signals. Colour light splitting distant signal aspects are more readable than semaphore splitting distant signal aspects. No semaphore splitting distant signals remain within the GB mainline railway. 2.5 Semaphore signal arm combinations Where a semaphore stop arm and a distant arm are provided at the same signal, the distant arm shall: a) Be positioned below the associated main stop arm and on the same signal post. b) Be presented in the OFF position only when the associated main stop arm is also presented in the OFF position Where a semaphore subsidiary signal is provided, the calling-on (subsidiary) arm shall: a) Be mounted below the associated main stop arm (and, where provided, the associated distant arm), and on the same signal post. b) Be presented in the OFF position only when the associated main stop arm is in the ON position Semaphore junction signals that convey routing information using stepped, multiple stop arms shall meet the following principles: a) A separate stop arm shall be provided for each route. b) The relative horizontal position of each stop arm shall correspond with the direction of the applicable diverging route relative to the other signalled routes beyond the junction. c) The uppermost stop arm shall apply to the route with the highest permissible speed. d) The relative vertical position of the other stop arms shall correspond with the relative permissible speed on each diverging route Semaphore junction signals that convey routing information using stacked, multiple stop arms or discs shall meet the following principles: a) A separate stop arm or disc shall be provided for each route. b) The uppermost stop arm or disc shall correspond with the most extreme left-hand route. c) The relative vertical position of each additional stop arm or disc shall correspond with the extent of the divergence from left to right. G Rationale These requirements are relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display combination. b) Poor spatial compatibility with track layout. Page 19 of 89

20 Supersedes Iss 1 (to correct formatting) and supersedes Guidance G Upper and lower quadrant semaphore signal arms are never combined within the same signal. G At main stop and distant signals: a) The main stop arm is positioned uppermost so that it is prominent, which helps users to read and interpret the MA information, irrespective of the distant signal aspect. Users understand that the main stop arm is always positioned uppermost. b) The information conveyed by the distant arm is only relevant when the main stop arm is in the OFF position. When the main stop arm is in the ON position, no MA is available. A distant OFF aspect presented in combination with a main stop aspect would convey conflicting MA information. G Figure 1 shows the permitted upper quadrant semaphore main stop and distant signal aspect combinations. The same signal arm ON and OFF aspect combinations apply also to lower quadrant signals. Figure 1: Permitted semaphore stop and distant signal arm combinations G The main stop arm and distant arm controls should incorporate a function to prevent the distant OFF aspect from being inadvertently presented when the main stop arm is in the ON position. G At semaphore subsidiary signals: a) Users interpret which type of MA is available using the combination of signal arm positions. b) Only one MA is conveyed at a time by each signal. A signal that presents a main proceed-aspect and a subsidiary proceed-aspect would convey conflicting MA information. G Figure 2 shows the appearance of permitted upper quadrant semaphore main and subsidiary signal arm combinations. The same signal arm ON and OFF aspect combinations apply also to lower quadrant signals. Page 20 of 89

21 Supersedes Iss 1 (to correct formatting) and supersedes Figure 2: Permitted semaphore main and subsidiary signal arm combinations G At semaphore junction signals: a) The stepped signal arm arrangement uses spatial compatibility with the track layout to help users work out which route is set. They interpret this by comparing the relative position of the signal arm displaying the OFF aspect with the position of the other stop arm(s) displaying the ON aspect(s). The relative vertical position of each stop arm helps them to decide which permissible speed applies on the route that is set. b) The stacked signal arm arrangement uses a consistent relationship between signal arm / disc vertical position and the route that is set to help users to interpret the MA and the direction of the route that is set. They do this by comparing the vertical position of the signal arm displaying the OFF aspect relative to the position of the other stop arm(s) displaying the ON aspect(s). G Figure 3 shows an example of a semaphore junction signal that uses stepped multiple stop arms to convey MA and routing information applicable to three directions (straight ahead, left hand and right hand) that have different permissible speeds. Figure 3: Example of a semaphore junction signal displaying stepped arms applicable to three routes with an MA shown towards the branch (route 3) Page 21 of 89

22 Supersedes Iss 1 (to correct formatting) and supersedes G G Where stepped signal arms are provided and the same permissible speed applies to more than one route at the junction, the applicable signal arms are usually mounted at the same height. Figure 4 shows an example of a semaphore junction signal that uses either stacked, multiple stop arms or discs to convey routing information applicable to three routes. Such an arrangement can be of benefit to overcome space limitations, for example, where shunting discs are positioned at a low level between adjacent lines. G G Figure 4: Example of a semaphore shunting signal that displays stacked arms or discs applicable to three routes (showing left- and right-hand divergences), with an MA along siding 1 The stacked arrangement is non-preferred and is not used for new main signals because: a) Unlike the stepped arrangement, the arrangement of signal arms does not support spatial compatibility with the track layout. b) Unlike the stepped arrangement, the height of the signal arm does not correspond with the relative permissible speed. Alternatively, for new semaphore signals, if there is a need to convey routing information, a signal arm / disc and alphanumeric route combination conveys more descriptive information about the route that is set. 2.6 Signal aspect and route combinations Junction signal aspect and route combinations shall be limited to the arrangements set out in Table 2: Page 22 of 89

23 Supersedes Iss 1 (to correct formatting) and supersedes Junction signal type Junction signal aspect type Route type All types Stop aspect A route and stop aspect combination shall be presented only for route proving purposes immediately before the proceed aspect is presented Colour light signal Proceed aspect Junction or alphanumeric or both Semaphore signal (all types) Independent or subsidiary position light signal Subsidiary position light signal Banner repeater indicator (repeating a junction signal) Proceed aspect Proceed aspect PoSA aspect White OFF or green OFF Alphanumeric Alphanumeric Junction or alphanumeric or both Arrow junction Table 2: Permitted signal aspect and route combinations When an alphanumeric route is presented by a main stop signal that also incorporates a subsidiary signal aspect, one of the following two options shall apply: a) The alphanumeric route s presented with main proceed-aspects shall be presented in a different position to any alphanumeric route s presented with the subsidiary aspect. Any alphanumeric route s presented with the subsidiary aspect shall appear to be at least 50% smaller than the alphanumeric route s presented with the main proceed-aspects. b) Where physical, environmental and structure gauge limitations mean that option a) of this clause is not feasible, a risk assessment shall confirm that the hazard of poor interpretability is controlled. G Rationale These requirements can be used to control the following driveability hazard precursors: a) Poor readability. b) Poor interpretability. Page 23 of 89

24 Supersedes Iss 1 (to correct formatting) and supersedes G G G G G G Guidance Signal aspect and route combinations convey the MA and routing information needed by users to understand which route is set and to decide if any action is required to control the speed of the train on the approach to the junction. An alternative method of conveying routing information in semaphore signalling areas is to provide a separate signal arm / disc for each route. Each junction signal aspect and route combination conveys a set of information needed to inform the train driving task at the junction ahead. Unusual or incompatible display combinations would adversely impact on readability or interpretability. For example, a junction is only presented with a colour light signal aspect, which has a similar readability performance. Consistency in presentation of junction signal aspect and route combinations supports the development and retention of train driver competence. Presenting a route with the stop aspect might mislead a user into anticipating a proceed aspect before the MA is available. However, an incorrectly presented route also has the potential to increase misinterpretation risk; therefore many signals are designed to confirm that the route is lit immediately before the junction signal proceed-aspect is presented. Where route indicator proving is provided, the proceed-aspect is presented as soon as possible after the route has illuminated. If the route is detected to be incorrectly presented, the main stop aspect continues to be presented. Three seconds provides enough time to complete the 'route indicator lit' proving function; any longer increases the probability of a driver error. Junction s convey directional information relevant to the junction ahead. Users interpret the direction of the divergence using the angle of the junction and its position relative to the signal aspect. Junction s are provided only at colour light main signals, which have a similar readability performance; however, it is permissible to present a junction in combination with a PoSA aspect when a failure means that the main proceed aspect cannot be lit. Figure 5 shows examples of a colour light junction signal displaying leftand right-hand junction s: a) A position 2 junction for a left-hand divergence. b) A position 5 junction for a right-hand divergence. Where it is necessary to locate junction indicators at the side of a signal head, to avoid confusion, positions 1-3 are placed on the left and positions 4-6 on the right. Page 24 of 89

25 Supersedes Iss 1 (to correct formatting) and supersedes Figure 5: Example colour light signal aspect and junction combinations (position 2 and position 5 shown) G G Alphanumeric s codify route and destination information using one or more alphanumeric characters. The signal aspect qualifies the alphanumeric as a route. Alphanumeric s presented on their own are used to convey other types of information (for example the 'BU' ). Figure 6 shows two examples of a colour light signal aspect and alphanumeric route arrangement. G Figure 6: Example colour light signal aspect and alphanumeric route combinations A colour light signal aspect presented with a junction and an alphanumeric route increases the complexity of the information being conveyed. This combination can provide an operational benefit if the directional information can be interpreted before the alphanumeric route is readable. For example, the junction can provide an early of a diverging route set towards a platform loop. The alphanumeric route provides further information about which platform the train is to use when the train is closer to the signal. Page 25 of 89

26 Supersedes Iss 1 (to correct formatting) and supersedes G Figure 7 shows an example of a colour light signal aspect presented in combination with a junction and an alphanumeric route. The junction becomes readable first so that the driver is able to understand that the MA is for a left-hand diverging route. The alphanumeric route becomes readable after the train has begun to decelerate and allows the driver to understand that the route is set into platform 3. The signal sighting assessment process is used to confirm the RRD of each route and the minimum reading time (MRT) values they support. G Figure 7: Example of a junction signal displaying a position 1 junction and alphanumeric route combination Figure 8 shows further examples of alphanumeric route s provided with different types of signal. G Figure 8: Examples of semaphore signal aspect and route combinations Figure 9 shows two examples of position light signal aspect and alphanumeric route combinations. G Figure 9: Examples of position light signal aspect and route combinations Signals that present similar alphanumeric route s with a permissive MA and a non-permissive MA increase misinterpretation risk if the signal aspect and route are not read at the same time. Physical limitations sometimes mean that it is not always possible to present alphanumeric route s that are significantly differentiated by display size and position. In this case, risk assessment is used to Page 26 of 89

27 Supersedes Iss 1 (to correct formatting) and supersedes G confirm that the proposed signal and indicator design support readability and interpretability at that location. Figure 10 shows an example of alphanumeric route s that use different position and size parameters to help users correctly interpret the MA and routing information being conveyed. The terms standard alphanumeric route indicator (SARI) and miniature alphanumeric route indicator (MARI) are sometimes used to describe equipment that displays alphanumeric route s. G Figure 10: An example of different alphanumeric route s presented with main proceed-aspects and subsidiary position light signal aspects Figure 11 shows an example of a route presented at a banner repeater indicator. This combination is one way of providing an early of the route set at the junction before the driver can read the junction signal and route combination. It is an alternative to providing a splitting banner repeater indicator. Figure 11: Example of a banner junction 2.7 Signal aspect and supplementary combinations Signal aspect and supplementary combinations shall be presented, only as set out in Table 3. Signal type Signal aspect Permitted supplementary Additional permitted supplementary Stop signal (excluding stop board) Stop aspect TT None Page 27 of 89

28 Supersedes Iss 1 (to correct formatting) and supersedes Signal type Signal aspect Permitted supplementary Additional permitted supplementary All stop signals Proceed-aspect 'CD' or 'RA' None Loading / unloading Flashing white light Isolated distant signal 'CD' or 'RA' None Banner repeater ON aspect None OFF aspect 'CD' or 'RA' None Stop board Stop aspect Flashing red light Flashing white light Steady yellow light Steady blue light Flashing blue light Table 3: Signal aspect and supplementary display combinations G G G Rationale This requirement can be used to control the following driveability hazard precursor: Poor interpretability due to: a) Inconsistent display combinations. b) Inconsistency in conveyed information. Guidance The signal sighting assessment considers the readability performance of the products being used in combination to confirm the displays will be readable when presented together at that location. Complex combinations of signal aspects, route s and signalling s would increase the likelihood of misinterpretation. In most cases, a maximum of three separate displays is sufficient to convey the MA, routing and any supplementary information needed at each location. Page 28 of 89

29 Supersedes Iss 1 (to correct formatting) and supersedes G G G G G The supplementary information conveyed at a signal is compatible with the MA information conveyed by the associated signal aspect. Other types of information that would conflict with the MA are not presented at the signal. The supplementary s associated with train dispatch procedures are only relevant when a train has an MA. The signalling system can include a control to prevent the RA from being presented when the signal is displaying a stop aspect. Correct operation of train dispatch s is also managed using operational procedures. At a station, a banner repeater indicator can be used to provide the function of a signal OFF indicator and combined with the CD/RA s. Two supplementary s are presented at a stop board protecting a LC where there are also other locally monitored systems. Drivers use the supplementary s to confirm that the infrastructure is correctly set for the train to proceed in accordance with the local operating instructions: a) When the locally monitored infrastructure is working correctly. b) When one of the locally monitored infrastructure features has failed or not operated. c) When a combination of the locally monitored infrastructure features has failed or not operated. On some lines fitted with a mechanical train-stop system, the TT is presented at the first stop signal beyond the trip-cock test equipment to provide information that the trip-cock test has failed. The stop aspect is presented because the trainstop function might not be working correctly on that train. Page 29 of 89

30 Supersedes Iss 1 (to correct formatting) and supersedes Part 3 Lineside Signal Aspects: Appearance and Meaning 3.1 Stop aspects Stop aspects shall convey the information and have the appearance set out in Tables 4 and 5. Page 30 of 89

31 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Main stop aspect Limit of MA Colour light signal head generating the red display Figure 12: Colour light signal (CLS) main stop aspect Semaphore main stop arm horizontally aligned (+5, -5 ) and a red signal light Figure 13: Semaphore main stop aspect Stop board Figure 14: Stop board Retroreflective buffer beam (in combination with two buffer-stop indicators vertically aligned - optional) Figure 15: Reflectorised buffer beam #1 Two red or two white buffer stop indicators positioned higher than the reflectorised buffer beam (optional) Table 4: Main stop aspects Page 31 of 89

32 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Shunting stop aspect Limit of MA Independen t position light signal generating the PLS red ON display Figure 16: Position light signal (PLS) stop aspect Semaphore miniature stop arm horizontally aligned (+5, -5 ) and a red signal light Figure 17: Miniature semaphore stop aspect Semaphore shunting disc horizontally aligned (+5, -5 ) and a red signal light or a floodlit disc Figure 18: Shunting disc stop aspect Table 5: Shunting stop aspects G G Rationale This requirement can be used to control the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. c) Poor concept compatibility. Guidance The seven options cover the complete range of products used for new and modified lineside signalling systems. All stop aspects support correct interpretation because they always convey the same information. Page 32 of 89

33 Supersedes Iss 1 (to correct formatting) and supersedes G G G G G Different stop aspect appearances within the field of vision can help train drivers to identify which stop aspect applies to the train being operated. Stop aspects support concept compatibility because: a) The colour red is associated with danger and stop messages in general. b) Users understand that signal arms, discs and position lights presented horizontally convey restrictive information. The distinctive appearance of the retro-reflective buffer beam helps users to interpret that the limit of MA is at a buffer stop. The design of buffer stops means that most retro-reflective buffer beams are positioned below the optimum position for visibility. Providing two buffer stop indicators at a higher level enhances the visibility of the retro-reflective buffer beam and therefore the interpretability of the limit of MA at the buffer stop. A signal sighting assessment is used to confirm: a) Whether buffer stop indicators are necessary or whether they can be omitted. b) The position of the buffer stop indicators relative to the buffer stop. c) The format and colour of the buffer stop s. Historical practice is to provide buffer stop indicators in the form of two lights positioned above the reflectorised buffer beam, either on the approach to the buffer stop or directly above it. White light indicators are provided only if the buffer-stop lights are positioned at the buffer beam and if it is assessed that red light indicators might adversely affect signal readability for train movements on other lines. 3.2 Shunting conditional stop aspect The shunting conditional stop aspect shall convey the information and have the appearance set out in Table 6. Designation Conveyed information Appearance Example Shunting conditional stop aspect Limit of MA when points are set towards a signalled line Independent position light signal generating the PLS yellow ON display Figure 19: Shunting conditional stop aspect Table 6: Shunting conditional stop aspect G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to inconsistent display appearance. Page 33 of 89

34 Supersedes Iss 1 (to correct formatting) and supersedes G G G G G Guidance The shunting conditional stop aspect always conveys the same MA information. Using this for new works has adverse implications on the railway undertaking because the unsignalled MA is dependent on the user correctly identifying the position of the facing points beyond the signal. The driver can ignore the aspect when the shunting movement is towards an unsignalled line. This signal aspect the following disadvantages: a) Signal lights presented horizontally are associated with restrictive aspects. b) Shunting conditional stop aspects do not support concept compatibility. The colour yellow is not usually associated with stop and danger messages, which places greater reliance on the user to correctly interpret the information conveyed. c) Users would not be able to distinguish between this aspect and stop aspects that indicate a definitive limit of MA. The colour red is not used because the limit of MA does not apply to shunting movements towards an unsignalled line. This signal aspect is typically provided at a ground frame, where a shunter is responsible for confirming the position of points and authorising train movements. An alternative solution that can avoid the disadvantages set out above, is to provide a shunt signal that presents the red stop aspect. The shunt aspect is presented for all train movements past the signal. A corresponding shunt signal can be provided for train movements in the opposite direction, together with controls that permit opposing shunting signals to show a shunt aspect at the same time. Historically, semaphore yellow disc signals have been provided. These are no longer permitted for new work. 3.3 Shunt aspect Shunt aspects shall convey the information and have the appearance set out in Table 7. Page 34 of 89

35 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Shunt aspect Shunt MA Independent position light signal generating the PLS steady OFF display Figure 20: PLS shunt aspect Semaphore shunting disc aligned at 45 (+20, -10 ) above or below horizontal and a green signal light or floodlight Figure 21: Semaphore shunt aspect (disc) Semaphore miniature stop arm aligned at 45 (+20, -10 ) above or below horizontal and a green signal light Figure 22: Semaphore shunt aspect (upper quadrant miniature arm) A position light signal generating PLS steady OFF display in combination with a colour light signal head generating the red display Figure 23: Subsidiary PLS shunt aspect - CLS Table 7: Shunt aspects G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: Page 35 of 89

36 Supersedes Iss 1 (to correct formatting) and supersedes a) Inconsistent display appearance. b) Inconsistent display meaning. G G G G G G Guidance The options cover the complete range of products used within new and modified lineside signalling systems. A subsidiary signal at a stop board has been used only. The permitted semaphore signal arm / disc alignment tolerance takes account of mechanical wear, heat expansion and mechanical adjustment without affecting the aspect appearance to the extent that the shunting MA would be difficult to interpret. Shunt aspects support concept compatibility because: a) Users understand that signal arms, discs and position lights presented in the upper quadrant or lower quadrant position are used to convey proceed-ma information. b) The colour green has concept compatibility with proceed messages in general. Independent shunt aspects support correct interpretation because they always convey the same information. The level of misinterpretation risk increases when a subsidiary position light signal is used to convey shunting MA and calling-on MA information at the same signal. Subsidiary shunt aspects combine a stop aspect and a shunt aspect in order to convey two pieces of information at the transition between two MAs, which may require the user to apply different operational rules, as follows: a) The limit of the previous MA, indicated by the main stop aspect. b) The start of a shunting MA, indicated by the subsidiary OFF aspect. Subsidiary shunt aspects are not intended to convey directional information; however, the relative position of the main and an offset subsidiary shunt aspect has the potential to lead the user into interpreting which route is set. A route can be presented if there is a need to reinforce users understanding of the route that is set. 3.4 Permissive aspect Permissive aspects shall convey the information and have the appearance set out in Table 8. Page 36 of 89

37 Supersedes Iss 1 (to correct formatting) and supersedes Description Conveyed information Appearance Example Permissive aspect Permissive MA A position light signal generating PLS steady OFF display in combination with a colour light signal head generating the red display Figure 24: Colour light permissive aspect A semaphore calling-on arm aligned at 45 (+20, -10 ) above or below horizontal and a green signal light positioned below a semaphore main stop arm horizontally aligned (+5, -5 ) and a red signal light Figure 25: Semaphore permissive aspect Table 8: Permissive aspects G G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. Guidance The two options provide for colour light signalling systems and semaphore signalling systems. Page 37 of 89

38 Supersedes Iss 1 (to correct formatting) and supersedes G G G G G G The permitted semaphore signal arm / disc alignment tolerance takes account of mechanical wear, heat expansion and mechanical adjustment without affecting the aspect appearance to the extent that the shunting MA would be difficult to interpret. The design of the signal arms means that the semaphore signal red light is larger than the subsidiary signal green light. The level of misinterpretation risk increases when a subsidiary position light signal is used to convey shunting MA and calling-on MA information at the same signal. Two signal aspects are combined, in order to convey two pieces of information at the transition between two separate MAs, which require the user to apply different operational rules: a) The limit of the previous MA, indicated by the main stop aspect. b) The start of a permissive MA, indicated by the subsidiary OFF aspect. When no MA is available: a) In colour light signalling areas, the signal presents only the main stop aspect. b) In semaphore signalling areas, the main stop arm and the calling-on arm are both horizontally aligned (+5, -5 ). Main and subsidiary aspect combinations are not intended to convey directional information; however, the relative position of the main and subsidiary parts of the signal aspect has the potential to lead the user into misinterpreting which route is set. A route can be presented with the permissive aspect if there is a need to reinforce users understanding of the route that is set. Historical practice at some locations was to present an alphanumeric with the subsidiary aspect to distinguish between 'calling-on', 'shunt-ahead' and 'warning'. 3.5 PoSA aspect Proceed on sight authority (PoSA) aspects shall convey the information and have the appearance set out in Table 9: Page 38 of 89

39 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example PoSA aspect PoSA MA A position light signal generating PLS flashing OFF display in combination with a colour light signal head generating the red display Figure 26: Subsidiary PoSA aspect An independent position light signal generating the PLS flashing OFF display Figure 27: Independent PoSA aspect Table 9: PoSA aspects The flashing display shall meet the following parameters: a) Flashing rate: 60 cycles per minute (+/-10). b) The two display elements flash synchronously. c) The two display elements are lit for 50% - 66% of each flashing cycle. d) Flashing cycles are of equal length. G G G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. Guidance The distinctive flashing appearance helps users to distinguish a PoSA MA. Users need to see at least three consistent flashing cycles to distinguish a flashing signal aspect from other signal displays. Approximately one flashing cycle per second means that a user has the opportunity to observe a minimum of seven flashing cycles when the train is approaching a signal that meets the minimum reading time. Page 39 of 89

40 Supersedes Iss 1 (to correct formatting) and supersedes G The PoSA aspect always conveys the same MA information. Users understand that flashing position light OFF aspects are presented only when the signalling system has a fault. PoSA aspects are associated with drive-on-sight operational rules aspect caution The 3-aspect caution shall convey the information and have the appearance set out in Table 10. Designation Conveyed information Appearance Example 3-aspect caution Non-permissive MA One signal section is clear Signalling braking distance is available A colour light signal head generating the single yellow display Figure 28: CLS 3- aspect caution A fixed distant board Figure 29: Distant board Table 10: 3-aspect caution G G G G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. Guidance The information conveyed by all cautionary aspects is intended to inform the driver s decision about when and where to apply the brakes in order to stop the train before it reaches the end of its MA. In 3-aspect TCB signalling areas, there is only one cautionary aspect, which supports correct interpretation because it always conveys the same MA information. The two options provide for worked signals, and signals that present fixed cautionary aspects. A fixed distant board provides only one signal aspect and is therefore only Page 40 of 89

41 Supersedes Iss 1 (to correct formatting) and supersedes G G used to remind the driver that the train is required to stop at the next signal, for example approaching a buffer stop or a fixed stop signal. The 3-aspect caution supports concept compatibility because: a) The colour yellow has concept compatibility with cautionary and warning messages in general. b) Users understand that a distant signal arm presented in the horizontal alignment is a cautionary aspect. RIS-0703-CCS sets out further requirements for TCB aspect sequences aspect cautionary aspects The cautionary aspects in 4-aspect signalling areas shall convey the information and have the appearance set out in Table 11. Designation Conveyed information Appearance Example 4-aspect first caution Non-permissive MA Two signal sections are clear Signalling braking distance is available A colour light signal head generating the double yellow display Figure 30: CLS 4- aspect double yellow caution 4-aspect single yellow caution Non-permissive MA One signal section is clear At least 33% signalling braking distance is available A colour light signal head generating the single yellow display Figure 31: CLS 4- aspect single yellow caution Table 11: Cautionary aspects in 4-aspect signalling areas G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: Page 41 of 89

42 Supersedes Iss 1 (to correct formatting) and supersedes G a) Inconsistent display appearance. b) Inconsistent display meaning. Guidance The information conveyed by all cautionary aspects is intended to inform the driver s decision about when and where to apply the brakes in order to stop the train before it reaches the end of its MA. G Two different displays differentiate between the different cautionary aspects in 4- aspect signalling areas. The two cautionary signal aspects convey information about the signalling braking distance on the approach to the limit of MA. G G G The 4-aspect cautionary aspects support concept compatibility because: a) The colour yellow has concept compatibility with cautionary and warning messages in general. b) The number of yellow lights corresponds with the number of clear signal sections ahead of the train. RIS-0703-CCS sets out further requirements for TCB aspect sequences. At some locations, non-standard cautionary aspects are used, which have the same appearance but convey different information about the number of signal sections clear and the availability of signalling braking distance. Compromising signal braking distance (SBD) and manipulating the signalling sequence to compensate for this creates an error trap for drivers. It fundamentally alters the meaning of cautionary aspects to drivers and erodes their ability to plan effectively. RIS-0703-CCS and research project T998 provide further guidance on this. 3.8 TCB unrestricted proceed aspect In track circuit block signalling areas, the unrestricted proceed aspect shall convey the information and have the appearance set out in Table 12. Page 42 of 89

43 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example TCB unrestricted proceed-aspect Non-permissive MA. Line clear A colour light signal head generating the green display Figure 32: CLS green main proceed aspect Semaphore main stop arm aligned at 45 (+20, -10 ) above or below horizontal and a green signal light Figure 33: Semaphore main proceed aspect (upper quadrant) Table 12: Unrestricted proceed aspect in TCB signalling areas G G G G G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. Guidance The two different options provide for colour light signalling systems and semaphore signalling systems. The permitted semaphore signal arm / disc alignment tolerance accommodates movement resulting from wear, heat expansion and mechanical adjustment without affecting the appearance to the extent that the MA would be difficult to interpret. If semaphore signals are provided, additional signal overrun risk controls may be necessary during conditions of poor visibility. TCB unrestricted proceed-aspects support concept compatibility because: a) The colour green has concept compatibility with proceed messages in general. b) Users understand that a semaphore stop signal arm presented in the upper quadrant or lower quadrant position is used to convey proceed information. Page 43 of 89

44 Supersedes Iss 1 (to correct formatting) and supersedes 3.9 Distant aspects Distant signal aspects shall convey the information and have the appearance set out in Table 13 and Table 14. Designation Conveyed information Appearance Example Distant ON aspect (includes intermediate block distant ON aspect) End of MA at the associated home signal or non-block stop signal Signalling braking distance is available (except for repeat distant ON aspects) A colour light signal head generating the double yellow display A colour light signal head generating the single yellow display Figure 34: CLS double yellow distant ON aspect Figure 35: CLS single yellow distant ON aspect Semaphore distant arm horizontally aligned (+5, -5 ) and a yellow signal light Figure 36: Semaphore distant ON aspect A fixed distant board Figure 37: Distant board Table 13: Distant ON aspects Page 44 of 89

45 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Distant OFF aspect (includes intermediate block distant OFF aspect) All associated stop signals are OFF Next block or token section is clear, or the next signal is a non-block stop signal displaying a proceed aspect A colour light signal head generating the green display Figure 38: CLS distant OFF aspect Semaphore distant arm aligned at 45 (+20, -10 ) above or below horizontal and a green signal light Figure 39: Semaphore distant OFF aspect (upper quadrant) Table 14: Distant OFF aspects G G G G G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. Guidance The three different product types provide for colour light signalling systems, semaphore signalling systems and signalling systems based on lineside signs. The permitted semaphore signal arm / disc alignment tolerance takes account of mechanical wear, heat expansion and mechanical adjustment without affecting the aspect appearance to the extent that the shunting MA would be difficult to interpret. The distant ON and distant OFF aspects support correct interpretation because they always convey the same MA information. The distant ON aspect is intended to inform the driver s decision about when and where to apply the brakes, in order to stop the train before it reaches the end of its MA. The distant OFF aspect is intended to help the driver understand that the MA includes the next block or token section. Distant ON aspects support concept compatibility because: a) The colour yellow has concept compatibility with cautionary and warning messages in general. Page 45 of 89

46 Supersedes Iss 1 (to correct formatting) and supersedes G G G G G b) Users understand that a distant signal arm presented in the horizontal alignment is a cautionary aspect. Distant OFF aspects support concept compatibility because: a) The colour green has concept compatibility with proceed messages in general. b) Users understand that a semaphore distant signal arm presented in the upper quadrant or lower quadrant position is used to convey proceed information. A semaphore distant aspect can be either presented on its own or as part of a main stop and distant signal aspect combination. An outer distant signal capable of presenting a double yellow or green aspect can be provided if the position of the signal presenting the yellow aspect is less than SBD from the home signal. This might be needed where signal boxes are closely spaced and absolute block working is retained for acceptance purposes. A fixed distant board provides only one signal aspect and is therefore only used to remind the driver that the train is required to stop at the next signal, for example approaching a buffer stop or a single line token exchange point. RIS-0703-CCS sets out further requirements for distant signal aspect sequences Block and non-block stop signal proceed aspects In non-tcb signalling areas, main stop signal OFF aspects shall convey the information and have the appearance set out in Table 15 and Table 16. Page 46 of 89

47 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Semaphore home signal OFF aspect Non-block semaphore stop signal OFF aspect Non-permissive MA One signal section is clear Semaphore main stop arm aligned at 45 (+20, -10 ) above or below horizontal and a green signal light Figure 40: Semaphore home OFF aspect (upper quadrant) Colour light home signal yellow-off aspect Colour light nonblock yellow-off aspect A colour light signal head generating the single yellow display Figure 41: CLS single yellow home OFF aspect Colour light home signal green-off aspect Colour light nonblock green-off aspect Non-permissive MA All associated stop signals are OFF A colour light signal head generating the green display Figure 42: CLS green home OFF aspect Table 15: Home signal, Section signal, Intermediate Block home signal, and non-block stop signal OFF aspects Page 47 of 89

48 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Section signal OFF aspect Intermediate block home signal OFF aspect Non-permissive MA Block, token or onetrain staff section is clear Semaphore main stop arm aligned at 45 (+20, -10 ) above or below horizontal and a green signal light Figure 43: Semaphore section signal OFF aspect (upper quadrant) Colour light section signal yellow-off aspect Non-permissive MA Block, token or onetrain staff section is clear as far as the home signal Signalling braking distance is available A colour light signal head generating the single yellow display Figure 44: CLS single yellow section signal OFF aspect Colour light section signal green-off aspect Intermediate block home signal green OFF aspect Non-permissive MA Block, token or onetrain staff section is clear A colour light signal head generating the green display Figure 45: CLS green section signal OFF aspect Table 16: Section signal and intermediate block home signal OFF aspects G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. Page 48 of 89

49 Supersedes Iss 1 (to correct formatting) and supersedes G G G G G G G G G Guidance The two different product types provide for colour light signalling systems and semaphore signalling systems. The permitted semaphore signal arm / disc alignment tolerance takes account of mechanical wear, heat expansion and mechanical adjustment without affecting the aspect appearance to the extent that the shunting MA would be difficult to interpret. Users understanding of the MA is also influenced by the aspect presented by the associated distant signal. Approach release requirements may apply to home signals when the distant ON aspect is presented. A colour light home signal yellow-off aspect conveys the same information as a semaphore home signal OFF aspect and is subject to the same approach release conditions as a semaphore home signal. A colour light home signal green-off aspect provides the operational advantage of repeating the associated distant signal OFF aspect at the home signal. Approach release requirements may apply to home signals if, at the time the train passed the distant signal, the distant ON aspect was presented. A colour light section signal or intermediate block home signal yellow-off aspect may also act as a distant ON aspect applicable to the next block or token section ahead. The green OFF aspect is presented only if the next stop aspect is preceded by a cautionary aspect at the required signalling braking distance. Lines signalled using the electric token block system or one-train staff system additionally require the transfer of a token or staff at or before a section signal. Semaphore signal and non-block stop signal OFF aspects support concept compatibility because: a) The colour green has concept compatibility with proceed messages in general. b) Users understand that a semaphore stop signal arm presented in the upper quadrant or lower quadrant position is used to convey proceed information. c) The colour yellow has concept compatibility with cautionary and warning messages in general. RIS-0703-CCS sets out further requirements for movement authorities Flashing signal aspects Flashing signal aspects shall convey the information and have the appearance set out in Table 17. Page 49 of 89

50 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example 4-aspect outer junction approach flashing caution 3-aspect junction approach flashing caution Non-permissive MA as far as the first signal beyond the junction SBD is available to the first signal beyond the junction The junction signal is displaying a cautionary aspect for a diverging route A colour light signal head generating the flashing double yellow display A colour light signal head generating the flashing single yellow display Figure 46: Flashing double yellow aspect Figure 47: Flashing single yellow aspect 4-aspect inner junction approach flashing caution Non-permissive MA as far as the first signal beyond the junction SBD is available At least 33% SBD is available to the junction signal A colour light signal head generating the flashing single yellow display with the appearance of a 4-aspect signal head Figure 48: Flashing single yellow aspect (4-aspect head) The junction signal is displaying a cautionary aspect for a diverging route Table 17: Junction flashing aspects The flashing display shall meet the following parameters: a) Flashing rate: 60 cycles per minute (+/-10). b) The two display elements flash synchronously. Page 50 of 89

51 Supersedes Iss 1 (to correct formatting) and supersedes c) The two display elements are lit for 50% - 66% of each flashing cycle. d) Flashing cycles are of equal length. G G G G G G G G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. Militating against this factor is relevant to the following hazard: a) A train exceeding the limit of MA. b) A train exceeding the permissible speed at a junction. c) Incompatibility of a train with the infrastructure beyond a junction. Guidance A distinctive flashing aspect appearance is used to convey information about the MA and the route set at the next diverging junction to support the actions necessary to either: a) Comply with the MA and the permissible speed on the diverging route. b) Stop the train if the route set at the junction is incompatible with the train being operated. Users need to see at least three consistent flashing cycles to distinguish a flashing signal aspect from other signal displays. Approximately one flashing cycle per second means that a user has the opportunity to observe a minimum of seven flashing cycles when the train is approaching a signal that meets the minimum reading time. British Rail specification BR 991 includes requirements for flasher unit flashing frequency and flashing pattern which are compliant with these flashing aspects. Providing a flasher unit with a different flashing parameter specification might result in issues of integration with existing signal lamp proving controls. Flashing cautionary aspects should always convey the same MA and routing information; however, they increase the workload associated with the interpretation task. A greater reliance on driver experience and route knowledge arises because flashing aspects: a) Do not always convey true MA information. This factor is associated with an increased level of signal overrun risk, which arises due to driver expectation of a less restrictive MA on the route that is expected. b) Do not give a positive of the direction or the destination of the diverging route. Other methods for conveying MA and advance routing information include: a) A preliminary route presented on the approach to the junction signal. b) A junction splitting distant signal aspect. Page 51 of 89

52 Supersedes Iss 1 (to correct formatting) and supersedes 3.12 Junction splitting distant aspects Junction splitting distant signal aspects shall convey the information and have the appearance set out in Table 18. Designation Conveyed information Appearance Example Splitting distant straight ahead caution righthand junction Non-permissive MA Two signal sections are clear Signalling braking distance is available Principal route set A double yellow caution positioned to the left-hand side of a single yellow caution. The single yellow is positioned so that is appears level with the bottom yellow light of the double yellow Figure 49: Splitting distant straight ahead caution - right-hand junction Splitting distant straight ahead caution left-hand junction A double yellow caution positioned to the right-hand side of a single yellow caution. The single yellow is positioned so that is appears level with the bottom yellow light of the double yellow Figure 50: Splitting distant straight ahead caution - left-hand junction Page 52 of 89

53 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Splitting distant left-hand junction caution Non-permissive MA Two signal sections are clear Signalling braking distance is available Left-hand diverging route set A double yellow caution positioned to the left-hand side of a single yellow caution. The single yellow is positioned so that is appears level with the top yellow light of the double yellow Figure 51: Splitting distant left-hand junction caution Splitting distant right-hand junction caution Non-permissive MA Two signal sections are clear Signalling braking distance is available Right-hand diverging route set A double yellow caution positioned to the right-hand side of a single yellow caution. The single yellow is positioned so that is appears level with the top yellow light of the double yellow Figure 52: Splitting distant right-hand junction caution Page 53 of 89

54 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Splitting distant straight ahead unrestricted proceed-aspect right-hand junction Non-permissive MA Line clear Principal route set A green light positioned to the left-hand side of a single yellow light. The green light is positioned so it appears higher than the yellow light Figure 53: Splitting distant straight ahead unrestricted proceed-aspect right-hand junction Splitting distant straight ahead unrestricted proceed-aspect left-hand junction A green light positioned to the right-hand side of a single yellow light. The green light is positioned so it appears higher than the yellow light Figure 54: Splitting distant straight ahead unrestricted proceed-aspect left-hand junction Splitting distant left-hand junction unrestricted proceed-aspect Non-permissive MA Line clear Left-hand diverging route set A green light positioned to the left-hand side of a single yellow light. The green light is positioned so it appears lower than the yellow light Figure 55: Splitting distant left-hand junction unrestricted proceed-aspect Page 54 of 89

55 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Splitting distant right-hand junction unrestricted proceed-aspect Non-permissive MA Line clear Right-hand diverging route set A green light positioned to the right-hand side of a single yellow light. The green light is positioned so it appears lower than the yellow light Figure 56: Splitting distant right-hand junction unrestricted proceed-aspect Table 18: Junction splitting distant signal aspects G G G G G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. Guidance Splitting distant signal aspects are made up of two colour light signal displays positioned side-by-side and vertically offset, each of which conveys direction specific MA information. Users understand that the less restrictive of the two displays is relevant to the route that is set Each splitting distant aspect combination supports correct interpretation because it always conveys the same MA and routing information. Unlike junction approach flashing aspects, these aspects convey true MA and routing information, are not associated with approach control requirements and are therefore not subject to SPAD risk that arises from driver anticipation of a less restrictive aspect. The examples shown assume a signal head comprising multiple, separate apertures. If different lit displays are generated by common display elements / apertures, splitting distant aspects incorporating a green display might have a slightly different appearance. Further rationale and guidance about the vertical displacement requirements for splitting distant signal aspects are given in RIS-0737-CCS. The appearance requirements apply the following spatial compatibility principles: a) The relative horizontal position of each signal aspect mimics the junction layout (for example, the left-hand signal aspect always applies to the left-hand route). b) The relative vertical position of each signal aspect corresponds to the relative permissible speed of each route where a higher position indicates a higher speed Page 55 of 89

56 Supersedes Iss 1 (to correct formatting) and supersedes G (for example, the signal aspect applicable to the principal route should be higher than the displays applicable to lower speed, diverging routes). The signal aspects shown in Table 18 are presented only when the junction signal is displaying a proceed-aspect. When the MA does not extend beyond the junction signal, the splitting distant signal presents the relevant caution or stop aspect in the signal head closest to the centre of the driver's field of vision. RIS-0737-CCS sets out further requirements for confirming the position of the signal aspect. Figure 57 shows examples of this for splitting distant signals mounted on the left-hand and right-hand sides of the line to which they apply. Figure 57: Examples of splitting distant signal aspects when the limit of MA is before the junction Page 56 of 89

57 Supersedes Iss 1 (to correct formatting) and supersedes Part 4 Banner Repeater Indications: Appearance and Meaning 4.1 Banner repeater s Banner repeater s shall convey the information and have the appearance set out in Table 19. Designation Conveyed information Appearance Example Banner-ON The repeated signal is presenting a main stop aspect Banner repeater head displaying a horizontal banner arm against a white background Figure 58: Banner ON Banner white-off The repeated signal is presenting a proceed-aspect (2- state banner repeater) The repeated signal is presenting a cautionary aspect (3-state banner repeater) Banner repeater head displaying an upper quadrant banner arm against a white background Figure 59: Banner white-off Banner green-off The repeated colour light signal is presenting a green aspect Banner repeater head displaying an upper quadrant banner arm against a green background Figure 60: Banner green-off Table 19: Banner repeater s G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. Page 57 of 89

58 Supersedes Iss 1 (to correct formatting) and supersedes G G G G G G Guidance Banner repeater s present an early of the MA available at the next stop signal. RIS-0737-CCS sets out further requirements on banner repeater indicators. Two types of banner repeater indicator are available: a) A 2-state indicator, which presents either the banner-on or the banner white-off. The information conveyed is differentiated by the alignment of the black banner arm, which is contrasted against a continuously illuminated white background. b) A 3-state, which presents either the banner-on, the banner white-off or the banner green-off. The information conveyed is differentiated by the alignment of the black banner arm and the colour of the illuminated background. The banner-on supports correct interpretation because it always conveys the same information. In semaphore signalling areas, only 2-state banner repeaters are provided. The banner white-off mimics the semaphore signal OFF aspect and therefore supports correct interpretation because it always conveys the same information. In colour light signalling areas, the 3-state banner repeater can improve interpretability because: a) A 2-state banner repeater indicator does not distinguish which proceed aspect is presented by the repeated signal. b) A 3-state banner repeater indicator provides a true repeat of the signal aspect presented by a 3-aspect signal; however, it does not distinguish between a double yellow and single yellow cautionary aspect presented by a 4-aspect signal. The banner green-off mimics the colour light signal green aspect and therefore supports correct interpretation because it conveys the same information. Banner repeater s support concept compatibility because users understand that horizontal signalling displays are used to convey restrictive information and upper quadrant signalling displays are used to convey proceed information. 4.2 Splitting banner s Splitting banner repeater s shall convey the information and have the appearance set out in Table 20, Table 21 and Table 22. Page 58 of 89

59 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Splitting banner- ON The repeated signal is presenting a main stop aspect Two banner-on s displayed side-byside Figure 61: Equal height banner-on Figure 62: Lefthand offset banner-on Figure 63: Righthand offset banner-on Table 20: Splitting banner repeater ON s Designation Conveyed information Appearance Example Splitting white banner-off (equal height left hand) The repeated signal is displaying a proceed aspect The left-hand route is set A banner white-off positioned to the left-hand side of a banner-on Figure 64: 2-state banner-off - lefthand equal height Page 59 of 89

60 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Splitting white banner-off (equal height right hand) The repeated signal is displaying a proceed aspect The right-hand route is set A banner white-off positioned to the right-hand side of a banner-on Figure 65: 2-state banner-off - righthand equal height Splitting white banner-off (stepped left-hand higher speed route) The repeated signal is displaying a proceed aspect The higher speed left-hand route is set A banner white-off positioned higher than and to the left-hand side of a banner-on Figure 66: 2-state banner-off - lefthand higher speed route Splitting white banner-off (stepped right-hand higher speed route) The repeated signal is displaying a proceed aspect The higher speed right-hand route is set A banner white-off positioned higher than and to the right-hand side of a banner-on Figure 67: 2-state banner-off - righthand higher speed route Splitting white banner-off (stepped left-hand route) The repeated signal is displaying a proceed-aspect The lower speed left-hand route is set A banner white-off positioned lower than and to the left-hand side of a banner-on Figure 68: 2-state banner-off - lefthand lower speed route Page 60 of 89

61 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Splitting white banner-off (stepped right-hand route) The repeated signal is displaying a proceed-aspect The lower speed right-hand route is set A banner white-off positioned lower than and to the right-hand side of a banner-on Figure 69: 2-state banner-off - righthand lower speed route Table 21: 2-state splitting banner repeater OFF s Designation Conveyed information Appearance Example Splitting white banner-off (equal height left hand) The repeated colour light signal is displaying a cautionary aspect The left-hand route is set A banner white-off positioned to the left-hand side of a banner-on Figure 70: 3-state banner white-off - lefthand equal height Splitting green banner-off (equal height left hand) The repeated colour light signal is displaying a green aspect The left-hand route is set A banner green- OFF positioned to the left-hand side of a banner-on Figure 71: 3-state banner green-off - lefthand equal height Splitting white banner-off (equal height right hand) The repeated colour light signal is displaying a cautionary aspect The right-hand route is set A banner white-off positioned to the right-hand side of a banner-on Figure 72: 3-state banner white-off - righthand equal height Page 61 of 89

62 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Splitting green banner-off (equal height right hand) The repeated colour light signal is displaying a green aspect The right-hand route is set A banner green- OFF positioned to the right-hand side of a banner-on Figure 73: 3-state banner green-off - righthand equal height Splitting white banner-off (stepped left-hand higher speed route) The repeated colour light signal is displaying a cautionary aspect The higher speed left-hand route is set A banner white-off positioned higher than and to the left-hand side of a banner-on Figure 74: 3-state banner white-off - lefthand higher speed route Splitting green banner-off (stepped left-hand higher speed route) The repeated colour light signal is displaying a green aspect The higher speed left-hand route is set A banner green- OFF positioned higher than and to the left-hand side of a banner-on Figure 75: 3-state banner green-off - lefthand higher speed route Splitting white banner-off (stepped right-hand higher speed route) The repeated colour light signal is displaying a cautionary aspect The higher speed right-hand route is set A banner white-off positioned higher than and to the right-hand side of a banner-on Figure 76: 3-state banner white-off - righthand higher speed route Page 62 of 89

63 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Splitting green banner-off (stepped right-hand higher speed route) The repeated colour light signal is displaying a green aspect The higher speed right-hand route is set A banner green- OFF positioned higher than and to the right-hand side of a banner-on Figure 77: 3-state banner green-off - righthand higher speed route Splitting white banner-off (stepped left-hand route) The repeated colour light signal is displaying a cautionary aspect The lower speed left-hand route is set A banner white-off positioned lower than and to the left-hand side of a banner-on Figure 78: 3-state banner white-off - lefthand lower speed route Splitting green banner-off (stepped left-hand route) The repeated colour light signal is displaying a green aspect The lower speed left-hand route is set A banner green- OFF positioned lower than and to the left-hand side of a banner-on Figure 79: 3-state banner green-off - lefthand lower speed route Page 63 of 89

64 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Splitting white banner-off (stepped right-hand route) The repeated colour light signal is displaying a cautionary aspect The lower speed right-hand route is set A banner white-off positioned lower than and to the right-hand side of a banner-on Figure 80: 3-state banner white-off - righthand lower speed route Splitting white banner-off (stepped right-hand route) The repeated colour light signal is displaying a green aspect The lower speed right-hand route is set A banner green- OFF positioned lower than and to the right-hand side of a banner-on Figure 81: 3-state banner green-off - righthand lower speed route Table 22: 3-state splitting banner repeater OFF s G G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. Guidance Splitting banner repeater indicators use spatial compatibility with the track layout to convey routing and permissible speed information. Two arrangements of splitting banner repeater indicators are available, as follows: a) An equal height splitting banner repeater for use at an equal speed junction uses the relative horizontal position of the banner-off and banner-on to indicate the left- or right-hand direction of the route set at the junction. b) A stepped splitting banner repeater, which also uses the relative vertical position of the banner-off and banner-on to indicate whether the higher speed or lower speed route is set at the junction. Page 64 of 89

65 Supersedes Iss 1 (to correct formatting) and supersedes G G G Both banner repeater indicator heads remain illuminated at all times to help users identify that it is a splitting banner repeater indicator on the approach to a diverging junction. When the junction signal is presenting a proceed aspect, users understand that the less restrictive of the two displays is relevant to the route that is set. The relative horizontal position of each mimics the junction layout (for example, the left-hand always applies to the left-hand route). A splitting banner repeater is provided only if it is recommended by a signal sighting committee. A green banner OFF should be presented for a lower speed diverging route only if the signal sighting committee confirms that drivers are able to distinguish the white banner-on applicable to the principal route at the required readable distance of the banner repeater indicator. Page 65 of 89

66 Supersedes Iss 1 (to correct formatting) and supersedes Part 5 Route Indications: Appearance and Meaning 5.1 Junction s Junction s shall convey the information and have the appearance set out in Table 23. Designation Conveyed information Appearance Example Position 1 JI The 1st left-hand diverging route is set An illuminated white bar of light presented in an upper quadrant position with the pivot end at the lower right Figure 82: Position 1 Junction indicator (JI) Position 2 JI The 2nd left-hand diverging route is set An illuminated white bar of light presented in a horizontal alignment with the pivot end at the right Figure 83: Position 2 JI Page 66 of 89

67 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Position 3 JI The 3rd left-hand diverging route is set An illuminated white bar of light presented in a lower quadrant position with the pivot end at the upper right Figure 84: Position 3 JI Position 4 JI The 1st right-hand diverging route is set An illuminated white bar of light presented in a lower quadrant alignment with the pivot end at the lower left Figure 85: Position 4 JI Position 5 JI The 2nd right-hand diverging route is set An illuminated white bar of light presented in a horizontal alignment with the pivot end at the left Figure 86: Position 5 JI Page 67 of 89

68 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Position 6 JI The 3rd right-hand diverging route is set An illuminated white bar of light presented in an upper quadrant position with the pivot end at the upper left Figure 87: Position 6 JI Table 23: Junction s (JI) G G G G G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. Guidance Junction s have the appearance of a bar of white light pointing from the signal aspect towards the general direction of the divergence that the train will take at the junction, relative to other possible routes. It is equally acceptable to use five individual lamps or a continuous bar of light generated by, for example, an array of light emitting diodes. Further guidance is provided in GKGN0657 Appendix B. Junction s are designed to mimic the direction of the diverging route relative to all of the other routes at the junction. Using a junction that does not mimic the track layout would make it difficult for users to correctly interpret which route is set. Users obtain directional information using the signal aspect and junction combination appearance. The junction signal should only present the proceed-aspect when the relevant junction is properly presented. If the junction is not properly presented, the user could misinterpret which route is set and the train could approach the junction at an excessive speed. The six junction s are sufficient for up to three left-hand diverging routes and three right-hand diverging routes; this is shown in Figure 88. Page 68 of 89

69 Supersedes Iss 1 (to correct formatting) and supersedes Figure 88: The relationship between each junction and the direction of the routes at a diverging junction G G Diametrically opposing junction positions on the same junction signal (positions 1 and 6, 2 and 5 or 3 and 4) are non-preferred because they have a similar angle and more reliance is placed on the relative positions of the junction and the signal aspect to interpret which route is set. Positioning the junction indicators to the side of the signal aspect can help with this. The selected junction mimics the direction of the divergence at the facing points rather than the geographical destination of the route. Figure 89 shows a junction where the left-hand and right-hand divergences both lead to a branch line that has a right-hand geographical direction. In this case, position 1 is presented when the route is set via the flyover, and position 4 is presented when the route is set to the right via the crossover. G Figure 89: Example of a position 1 or position 4 junction on the approach to a right-hand flying junction RIS-0737-CCS sets out the requirements for the signal sighting committee to assess the interpretability of the junction s. Page 69 of 89

70 Supersedes Iss 1 (to correct formatting) and supersedes 5.2 Preliminary route s Preliminary route s (PRIs) shall convey the information and have the appearance set out in Table 24. Designation Conveyed information Appearance Example Position 0 PRI The principal route is set at the next diverging junction An illuminated arrow, vertically aligned with the arrow head at the top Figure 90: Position 0 preliminary route (PRI) Position 1 PRI The 1st left-hand diverging route is set at the next diverging junction An illuminated arrow, in the upper quadrant position with the arrow head at the upper left Figure 91: Position 1 PRI Position 2 PRI The 2nd left-hand diverging route is set at the next diverging junction An illuminated arrow, horizontally aligned with the arrow head at the left Figure 92: Position 2 PRI Page 70 of 89

71 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Position 3 PRI The 3rd left-hand diverging route is set at the next diverging junction An illuminated arrow, in the lower quadrant position with the arrow head at the lower left Figure 93: Position 3 PRI Position 4 PRI The 1st right-hand diverging route is set at the next diverging junction An illuminated arrow, in the lower quadrant position with the arrow head at the upper right Figure 94: Position 4 PRI Position 5 PRI The 2nd right-hand diverging route is set at the next diverging junction An illuminated arrow, horizontally aligned with the arrow head at the right Figure 95: Position 5 PRI Position 6 PRI The 3rd right-hand diverging route is set at the next diverging junction An illuminated arrow, in the upper quadrant position with the arrow head at the lower right Figure 96: Position 6 PRI Table 24: Preliminary junction s Page 71 of 89

72 Supersedes Iss 1 (to correct formatting) and supersedes No shall be presented when the junction signal is displaying a main stop aspect. G G G G G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. Guidance Preliminary route s convey information about the direction of the route that is set at the next diverging junction. They mimic the direction of the set route relative to all of the other routes at the junction. Drivers use their route knowledge and experience to interpret which route is set and then decide what action is required to control the movement of the train on the approach to the junction. Preliminary route s have the appearance of a white arrow pointing towards the general direction of the divergence that the train will take at the junction signal, relative to other possible routes. A white arrow pointing in the direction of the set route supports concept compatibility with directional information. Unlike junction s, preliminary route s are presented independently of a signal aspect and therefore there is no reference point to differentiate between left-hand and right-hand directions. Instead, the direction of the route that is set is conveyed by the arrow head. The seven preliminary route s are sufficient for the principal route and up to three left-hand diverging routes and three right-hand diverging routes: a) Positions 1 to 6 repeat the directional information conveyed by the junction at the next junction signal. b) Position 0 provides a positive that the principal route is set. c) The absence of an implies that the junction signal is presenting the main stop aspect. 5.3 Alphanumeric route s Alphanumeric route s (ARIs) shall convey the information and have the appearance set out in Table 25. Page 72 of 89

73 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Alphanumeric route The route is set towards the indicated destination Any horizontally aligned combination of one, two or three upper case alphanumeric characters, limited to the following: A B C D E F G H Figure 97: 'Standard' ARI (SARI) Figure 98: 'Miniature' ARI (MARI) I J (non-preferred) K L M N O (non-preferred) P R S T U V (non-preferred) W Y Z The route is set towards a limit of shunt or in the opposite direction to the normal flow of traffic X Figure 99: MARI 'X' Table 25: Alphanumeric route s Where a signal has more than one contra-direction route, the relevant alphanumeric route shall combine the letter X with one or two additional characters. Page 73 of 89

74 Supersedes Iss 1 (to correct formatting) and supersedes G G G G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. The letter X is reserved for moves in the opposite direction to the normal flow of traffic because of the criticality of the limit of MA along the opposite direction to normally signalled movements. Letter Q is not used because it has a similar appearance to numeral 0 and so could be misread by a user. A maximum of three characters is specified because a greater number would increase user workload and make the more difficult to read. G G Guidance Alphanumeric route s have the appearance of one, two or three alphanumeric characters positioned adjacent to the relevant signal aspect. Alphanumeric route s convey information about the route and destination beyond each diverging junction. Drivers use their route knowledge and experience to interpret which route is set and then decide what action is required to control the movement of the train on the approach to the junction. G Letters I, J, O and V are non-preferred because they could be misread as numerals 1, 0 or a directional arrow. The letter R is non-preferred because this could be confused with the 'right away' (RA). G G The signalling system is usually designed so that junction signals only present the proceed-aspect when the relevant alphanumeric route is detected to be properly presented. If the route is not properly presented, the user could misinterpret which route is set and the train could approach the junction at an excessive speed. If the alphanumeric is generated using a matrix of individual light sources, sufficient light sources should be detected to be alight, in order to present a proceed-aspect for a diverging route. Combinations of light source failure have the potential to change the to something else; for example, the numeral '8' could appear as a numeral '6' or the letter 'E' as an 'F'. Replacing existing equipment with a product that reliably displays complete alphanumeric characters can eliminate this potential hazard. Consistent application of alphanumeric characters helps users to correctly interpret the information being conveyed. Table 26 shows typical applications of characters and numerals. Indication Conveyed information Remarks Numeral(s) or Letter(s) Platform or line identity None Page 74 of 89

75 Supersedes Iss 1 (to correct formatting) and supersedes Indication Conveyed information Remarks C Calling-on Clarifies the type of MA available D Down Sometimes supplemented with a line identity U B F G L M P S T Up Branch Bay Fast Goods Local or Loop Main Passenger Slow Siding Through Sometimes supplemented by a direction or route Y Yard None SDG Siding None G Table 26: Typical alphanumeric route s The alphanumeric s shown in Table 27 are used for other purposes and therefore unsuitable for indicating which route is set at a junction. Indication OFF BU CD Application Signal OFF LC Train dispatch system RA Page 75 of 89

76 Supersedes Iss 1 (to correct formatting) and supersedes Indication TT Application Mechanical trainstop system Table 27: Alphanumeric s that are used for applications other than route s Page 76 of 89

77 Supersedes Iss 1 (to correct formatting) and supersedes Part 6 Equipment Status Indications: Appearance and Meaning 6.1 Infrastructure not operated Infrastructure not operated s shall convey the information and have the appearance set out in Table 28. Designation Conveyed information Appearance Example Infrastructure not operated Locally monitored infrastructure not operated One flashing red light Figure 100: Infrastructure not operated Table 28: Locally monitored infrastructure not operated The following flashing parameters shall apply: a) Flashing rate: 120 cycles per minute (+/-6). b) Lit for nominal 20% of each flashing cycle. c) Each flashing cycle of equal length. G G G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. Militating against this factor is relevant to controlling the following hazard: Train operation over infrastructure that is not correctly set. The consistent flashing parameters, which are different from flashing signal aspects, help users to detect and identify these s in the operational context. G G Guidance Flashing red s support correct interpretation because they always convey the same information This is typically applied on the approach to the following types of locally monitored infrastructure: a) Facing points. b) Trailing points (not trailable). c) automatic open LC (AOCL). d) automatic barrier LC (ABCL). Page 77 of 89

78 Supersedes Iss 1 (to correct formatting) and supersedes G G e) train crew operated LC (TMO). The distinctive flashing red appearance helps users to: a) Locate and identify locally monitored infrastructure ahead of the train. b) Apply the relevant operational rules when locally monitored infrastructure has not operated. Flashing red s support concept compatibility because: a) The colour red has concept compatibility with danger and stop messages in general. b) Users understand that flashing red s are associated with the requirement to stop the train on the approach to an obstruction. 6.2 Facing points set Facing points set s shall convey the information and have the appearance set out in Table 29. Designation Conveyed information Appearance Example Facing points set Locally monitored points are correctly set One steady yellow light Figure 101: Facing points set Independent position light signal generating the PLS steady OFF display Figure 102: Facing points set using position light signal OFF display Table 29: Facing points set G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. Page 78 of 89

79 Supersedes Iss 1 (to correct formatting) and supersedes G G G G Guidance The facing points set helps users to: a) Locate and identify locally monitored facing points. b) Understand that the points are correctly set for the train being operated. The information conveyed by points set s informs the driver s decision about when and where to apply the brakes in order to comply with the permissible speed at the points (typically 25 km/h or less). The similar appearance of the yellow points set to a cautionary signal aspect is consistent with the limit of MA at the stop signal beyond the facing points (usually a stop board). The colour yellow has concept compatibility with cautionary and warning messages in general. On lines fitted with the 'no-signaller token - remote' (NSTR) system, the token is released without confirmation that the passing loop at the end of the section is clear. In this case, the position light OFF aspect is used to indicate the permissive nature of the MA beyond the facing points and that the points are correctly set into the loop. 6.3 Locally monitored LC s Locally monitored LC s shall convey the information and have the appearance shown in Table 30. Designation Conveyed information Appearance Example Locally monitored LC Locally monitored LC operating correctly One flashing white light Figure 103: Locally monitored LC 'Barriers Up' LC barriers are fully raised Alphanumeric characters 'BU' (non-flashing) Figure 104: BU Table 30: Locally monitored LC The following flashing parameters shall apply to the flashing white light : a) Flashing rate: cycles per minute. b) Lit for 50% - 66% of each flashing cycle. c) Each flashing cycle of equal length. Page 79 of 89

80 Supersedes Iss 1 (to correct formatting) and supersedes G G G G G G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. The consistent use of the flashing parameters helps users to detect and identify the driver s LC white in the operational context. Guidance The flashing white was developed for locally monitored LC applications so that a filament lamp could be controlled by the flasher unit used to control the red road light signals, which are designed to be compliant with the relevant LC regulations. The distinctive flashing white appearance helps users to: a) Locate and identify the locally monitored LC ahead of the train. b) Apply the operational rules for train operations at the LC. All flashing white s support correct interpretation because they are only provided at locally monitored LCs, and always convey the same information. Users understand that flashing white s are associated with train movements over locally monitored LCs. The 'BU' is presented to the driver after the train has passed over a train crew operated LC, where an auto-raise function is provided to reopen the road after the passage of the train. Users understand that the alphanumeric BU is the abbreviation for Barriers Up. Absence of the implies that the LC barriers have failed to fully raise. 6.4 TPWS s TPWS s shall convey the information and have the appearance set out in Table 31. Designation Conveyed information Appearance Example TPWS set TPWS intervention is set at the stopboard One steady blue light Figure 105: TPWS set Page 80 of 89

81 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example TPWS disarmed TPWS is disarmed at the stop-board One flashing blue light Figure 106: TPWS disarmed TPWS failed TPWS has failed Unlit N/A Table 31: TPWS s The following flashing parameters shall apply: a) Flashing rate: 120 cycles per minute (+/-6). b) Lit for nominal 20% of each flashing cycle. c) Each flashing cycle of equal length. G G G G G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. The consistent use of these flashing parameters, which is different from flashing signal displays, helps users to detect and identify these s in the operational context. Guidance The distinctive blue helps users to understand that train movements beyond the stop board are protected by the TPWS. Users understand that blue s are associated with train movements at stop boards where TPWS is provided. TPWS s help users to apply the operational rules applicable to train movements beyond the associated stop board and confirm whether or not the TPWS is working correctly. TPWS steady and flashing s support correct interpretation because they always convey the same information and are only associated with TPWS at a stop board. Page 81 of 89

82 Supersedes Iss 1 (to correct formatting) and supersedes 6.5 Mechanical trainstop system Mechanical trip-cock system status s shall convey the information and have the appearance set out in Table 32. Designation Conveyed information Appearance Example Trip-cock test Trip-cock test underway Alphanumeric characters TT Figure 107: Tripcock test N/A Trip-cock test OK Unlit N/A Table 32: Mechanical trip-cock test G G G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. Guidance Users understand that the alphanumeric TT is the abbreviation for tripcock test. Users use the TT to confirm that the vehicle mounted trip-cock is operating within its permitted design tolerances and is therefore capable of interacting with the trackside mechanical train-stop equipment to apply the train brakes. The TT supports correct interpretation because it always conveys the same information. Page 82 of 89

83 Supersedes Iss 1 (to correct formatting) and supersedes Part 7 Operating Indications: Appearance and Meaning 7.1 Train dispatch system s Train dispatch system s shall convey the information and have the appearance set out in Table 33. Designation Conveyed information Appearance Example Signal OFF The associated stop signal is presenting a proceed-aspect Characters OFF Presented either on its own or in combination with a signal identity or direction identity Figure 108: OFF Close doors Close train doors Characters CD Figure 109: CD Right away Right away Characters RA Figure 110: RA Table 33: Train dispatch system s Where an indicator displays CD and RA, the CD shall be presented first and the RA shall supersede the CD. G G G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. Trains are not given a right away until the doors have been closed. Guidance These s support correct interpretation because they always convey the same information: Page 83 of 89

84 Supersedes Iss 1 (to correct formatting) and supersedes G G a) Users understand that the term OFF means that the train has an MA, either conveyed by a signal aspect or using the European Train Control System (ETCS). b) Users understand that CD and RA are abbreviations for close doors and right away respectively. CD and RA s are usually controlled by platform staff using a control device located on the station platform. The signalling system can be designed to prevent an incorrect sequence of s from being presented due to incorrect operation. Where a signal OFF is presented on a platform that includes more than one signal, or where trains may be dispatched in either direction, the OFF is supplemented with additional information to help users correctly interpret which signal it applies to. Examples include: a) UP OFF or DN OFF (Direction). b) AB103 OFF (Signal identity). The additional information is provided using either a lineside operational sign positioned adjacent to the OFF indicator or additional characters within the lit OFF. 7.2 Loading and unloading s Loading and unloading s shall convey the information and have the appearance set out in Table 34. Designation Conveyed information Appearance Example Stop Stop immediately Three red lights aligned horizontally Figure 111: Stop Position 1 shunting Prepare to stop Three white lights aligned at 45 left hand raised Figure 112: Prepare to stop Position 0 shunting Forwards slowly Three white lights aligned vertically Figure 113: Forwards Page 84 of 89

85 Supersedes Iss 1 (to correct formatting) and supersedes Designation Conveyed information Appearance Example Position 4 shunting Reverse slowly Three flashing white lights aligned at 45 right hand raised Figure 114: Reverse Table 34: Loading and unloading s The flashing display shall meet the following parameters: a) Flashing rate: 60 cycles per minute (+/-10). b) The three display elements flash synchronously. c) The two display elements are lit for 50% - 66% of each flashing cycle. d) Flashing cycles are of equal length. G G G G Rationale This requirement is relevant to controlling the driveability hazard precursor: Poor interpretability due to: a) Inconsistent display appearance. b) Inconsistent display meaning. Guidance Four distinct s are used to convey train movement information between a local freight terminal operator (typically located at a local control point) and the person controlling the train. These s support correct interpretation because they always convey the same information. The movement and direction information is distinguished by colour, alignment and whether or not the is flashing. The stop supports concept compatibility because: a) The colour red has concept compatibility with danger and stop messages in general. b) Users understand that signal arms, discs and position lights presented horizontally convey restrictive information. Page 85 of 89