I posted about this previously in the Peak Forest thread, but I think it's actually a more general problem - so here's a thread specifically dedicated to it. It's a general feature of railway signalling that, between a signal showing Clear and one showing Danger, there should be one showing Caution. This allows a fast-moving train to slow down in time to stop. Indeed, it's often said by signalmen that the Distant signal - the one capable of showing Caution aspects - is the most important type of signal, even though the Home signal - capable of showing Danger - is the one the train must actually stop at. In modern signalling, most signals are both Home and Distant signals combined, capable of showing any of the Clear, Caution or Danger aspects as appropriate. These are represented in TSW's HUD as green, yellow, and red icons respectively. Many TSW players rely on this HUD, instead of thoroughly learning the signalling system for the route they drive. However, there are signals on some routes which cause the HUD to give misleading information to the player. That's what this thread is about. The most numerous of these signals is the German "Vr" Distant signal, which is in fact a survival to the modern day of the old semaphore Distant signal, just with the mechanical arms removed. Often it is mounted directly below a "Hp" signal and is read in combination with it. "Vr" is capable of showing two different kinds of Caution signal: "Expect stop" and "Expect slow". The combination of "Hp" and "Vr" is also capable of showing "Stop", "Slow, expect clear", "Slow, expect slow", and "Slow, expect stop". This is in addition to the basic "Clear" aspect that all German signals are capable of showing. However, so far as TSW's HUD is concerned, a "Vr" signal does not exist, whether combined with a "Hp" or standing by itself. Only "Hp" heads are shown in the HUD, and both "Clear" and "Slow" aspects appear as green icons, even if a "Vr" head mounted below is showing "Expect stop". In the above picture, the HUD would inform the player only of the further Hp+Vr signal, showing red, and ignore the nearer Vr signal showing "Expect stop". If that signal were showing "Slow, expect stop" - the most restrictive proceed aspect bar a shunting signal - the HUD would show a green icon, implying complete freedom to manoeuvre. Contrast that to a "Ks" signal, which can directly show all of the aspects that a "Hp" and "Vr" combination can, using fewer lamps and a smaller signal head; it is designed as a direct replacement and, in principle, can slot into an existing signalling design based on "Hp" and "Vr" signals. Here, the "Clear, expect stop" aspect (a single yellow lamp) is correctly reflected in the HUD with a yellow icon, even though it has exactly the same meaning as a "Hp+Vr" signal showing the same aspect as a combination of green and yellow lamps, or a standalone "Vr" signal showing its most restrictive aspect. On German routes, this is actually not too serious a problem, because the Germans generally do not put "Hp" signals at close spacings. Thus, when you pass a signal showing green in the HUD at line speed, you have a reasonable distance (at least 1km) to brake before a following signal showing red in the HUD. On modern British routes, the multiple-aspect colour-light signals are similar in principle to the "Ks" signal shown above. The HUD likewise shows Caution and Advance Caution aspects from these signals with yellow icons, and only a true Clear aspect gets a green icon. However, British signalling also has standalone Distant signals which differ from others only in that they are incapable of showing a Danger aspect - but again, as far as the HUD is concerned, they do not exist. They player might not be concerned about this because the following signal is shown instead. The situation is considerably more serious, however, with British semaphore signalling on the Absolute Block system, which appears in both Spirit of Steam and Peak Forest. This system is practically unique in that a single Distant signal (whether of the semaphore or colour-light variety) may (and frequently does) warn that any of several subsequent Home signals, standing between itself and a subsequent Distant signal, are at Danger. Very often only the last Home signal in this sequence, known as the "section signal", is at Danger because it protects the longest section of line. But TSW's HUD will completely ignore the Distant signal warning of this, instead showing the player green icons for the first Home signal in this sequence - and thus no warning of the actual Danger signal, until it is too late to stop at it. It should be noted that this fault was also present in RailWorks (aka Rail Simulator or Train Simulator Classic) throughout its lifetime, and was complained about as early as the Somerset & Dorset Joint Railway (SDJR) route which at one time was part of the standard release package. I consider it very unfortunate that this was carried over into TSW, since DTG have been aware of the consequences of this implementation for many years - indeed, since before they renamed themselves (yet again) to DTG - and TSW represented an opportunity to discard technical debt of exactly this type. Still, at least the Distant signals themselves now behave more appropriately, instead of repeating only the first Home signal's aspect. There are four changes to the HUD behaviour that would considerably improve the player experience: Distant signals should be indicated in the HUD just like Home signals are. Combined Home and Distant signals (both British and German) should have HUD indications consistent with the combined aspect, not only the Home aspect. Sequences of consecutive Home signals, incapable of showing a Caution aspect on approach to a signal at Danger, should artificially show Caution in the HUD instead of Clear, to remind the player of this special hazard. Signals commencing or warning of a reduced speed limit (ie. Hp2 and/or Vr2 in the German system) should be treated as Caution aspects in the HUD. In a related problem, I've noticed that shunting signals' proceed aspects are also indicated with green icons in the HUD, even though they have a very different meaning to a main signal showing Clear. In fact, their meaning is more restrictive even than a main signal's Caution aspect, as it doesn't even guarantee that the section is clear of obstructions (such as another train) to the next signal. There should, therefore, be a fourth icon in the HUD to indicate "proceed for shunting" - I would suggest using white. The HUD indications for shunt signals should also be suppressed when running with the authority of a main signal, to prevent player confusion.
I don't think it's literally copied, but probably the same "tried and tested" principles were cribbed from extensively when building TSW's signalling system. The same can be seen in most of TSW's diesel-hydraulic traction, even though we know for certain that TSW's physics implementation has nothing in common with what came before.
I have actually got in the habit of tabbing the signaller on quite a few occasions but have still got caught out with the odd SPAD. It is easier with the diesel traction as you generally get a better view of the signalling than looking down the boiler of a steam loco, even worse when it’s raining and you can’t fold back the cinder guard. In reality on a steam loco the fireman would be looking out for signals too, especially when running around a right hand curve and visibility from the left hand side of the cab is virtually none existent. There’s no quick way of snapping to the other head out view either, without trawling through the various camera positions. Even worse on the 4F when running tender first as changing the view then going back resets to the default position, rather than leaving the view angled backwards in direction of travel.
No, not really... The most likely reason why distance signals behave similarly in TSC and TSW is that, as far as the game is concerned, they are not really a signal - they do not define blocks, and don't protect part of a track. They are just an extended arm of the main signal, and their state is 100% based on the main signal. I woudln't be surprised if in-game the signal points, which SPADs you, are actually invisible, and have assets linked to them (main signal, distant). For this reason the distance to signal on HUD is always the distance to this SPAD point, even in cases where the signal is on different place (I.e. on Arosa, where there is a combined signal after the junction, and the SPAD point is before the junction). This is most likely why distance signals are opaque for the hud, as they are opaque even for the dispatcher and signaling system, as are all other signalling assets. The signaling system only sees a point on track, which the signal protects.
I think the same is true of distant or repeater signals on the UK network. A lot of the time you will see a yellow signal out in the middle of nowhere that is not shown on the HUD at all. I think it's because AT THAT POINT there is nothing you really have to do or obey. I agree that all signals that are relevant to the driver should be noted on the HUD, but it's how do you do that without falling foul of accessibility issues.
Nice summary. Northern transpennine also suffers from the semaphore issues with the added bonus that the colour-light signals and semaphores do not communicate with each other. So you fly past a semaphore distant at 'clear' and straight into a colour-light at 'danger'.
I believe this is the case across TSW, but naturally is especially annoying in Germany, the UK and Switzerland because they rely on advance/Vorsignals so heavily. It is much less a problem on US routes because (for the most part) all signals are potentially main signals, i.e. can display a Stop aspect, and cautions and the like are displayed on preceding main signals, which the game can "see"
I think it's likely this way because when DTG were writing the signalling interpretation of the HUD they were working on the colour light aspects as displayed in the UK, without implementing even the UK semaphore signalling aspect where the distant signal can cover several upcoming signals. In essence that first signal being at caution should mean all signals are read by the HUD as "at caution" until all signals in that area are "at clear", but the game doesn't do that, only reading the next signal very literally
The first TSW route wasn't even in the UK, but American. So that's what the initial signalling build would have focused on. All the same, this is the same company which was simultaneously publishing RailWorks and its mountain of DLC, which included all manner of signalling, and UK semaphore signalling was a very well-known weak point of RailWorks. There was at least one route (Wherry Lines) which provided an alternative UK semaphore signalling set which did behave more like the real thing, serving as a contemporary example of what was needed. It's a core tenet of software engineering that you at least leave room for plausible future requirements in an architecture, especially when you have painful examples of technical debt sitting right there as a warning. There's enough information in the signalling architecture to trigger AWS, TPWS, and PZB magnets appropriately. At least some of these are associated with Distant signals as well as Home signals, or even primarily Distant signals. Early AWS installations, in the days when Absolute Block was still far more common than multiple-aspect Track Circuit Block, were at Distant signals but not Home signals. So I don't think there's a big technical barrier to implementing this in TSW; just somebody hasn't recognised the requirement to do so.
I think that DTG assume that most players use the HUD to read upcoming signals rather than observing line side aspects and most players have only a very basic understanding of railway signalling, so they tried to make it as simple as possible by having just the 3-aspect signals in " traffic light order ". In more recent routes, some of which have in- cab signalling and more complicated interlocking, the HUD becomes much less reliable. This is where the developer runs into trouble and the players can experience " signal nightmares ", especially on NA routes like BPE and NYT. You need experts like Brandon and Joe to sort out both timetable and signalling, which are closely related in the game. And maybe a HUD redesign. Because I, for one, am not prepared to drive HUDless on any route, though on the Acela, for instance, you have to drive according to in- cab signals rather than anything on the HUD, which can be very misleading.
There's more than one route building team, and no matter what the initial route was, the programming of the HUD wouldn't necessarily have been done by or in consultation with a route team
I don't think you do... I think the HUD needs to be more than just "what's the next signal doing?" in instances where signals or repeaters are acting in concert, so as per my previous example where the distant signal can cover several upcoming signals. In essence that first signal being at caution should mean all signals are read by the HUD as "at caution" until all signals in that area are "at clear" This would require a change in programming and setup of signals where such states can exist, but shouldn't be beyond the wit of man to implement
Since the Distant signals on PFR do, in fact, already reflect the full sequence of Home signals ahead, the information is already available in the system to implement appropriate HUD behaviour. It just needs to be pointed at the right place to make it happen.
How will you get this around the accessibility though? It needs to have an icon/ pattern otherwise it falls on the wrong side for people with colour deficiencies. (Like red, yellow and green having a dash and set angles)
Well, the current icon set is clearly inspired by the PRR signal system, which uses both light positions and colours to reinforce each other. Green has a vertical dash, yellow has a diagonal one, and red has a horizontal one. In keeping with that system, the white icon could use a shorter dash, oriented diagonally in the opposite direction to the yellow icon. Thus the only icon it might be confused with is the icon for Caution, which is not too bad.
This is an asumption, there might not be enough data. For the HUD to show distance it needs to know where on track the signal asset asociated with the signal point is... at this point it might not know that. It knows the world location of the asset. But does the asset belong to the left, or right track, and at which specific point? So far, there was no need for this kind of linkage, as nothing happens when you pass the distant signal. Signal changes only when you pass a specific point on track, it it this specific point on track we currently have the HUD distance indication (and not the main signal 3D asset).
I believe they're saying something along the lines of "If the signals can work it out then the signalling system could 'tell the HUD' what to show"
The singaling system can work out what should the state of an asset tied to one, or multiple, signal points should be. To show distance and aspect this still isn't enough. First, you need to know the track distance to the point of the distance signal, for this a point on the track spline itself needs to be defined. The thing is, that this point might even not be defined yet, as it there is no game system tied to that point. The AI doesn't care about distance signals, and nothing happens when you cross a distant signal. So distant signal can very well be just an asset tied only to the main signal point, and to no other point on the track. So there is way, in the current system, how to show distance to distant signal. You then also need to do stuff like tying the combined german signals together, becasue it might be two different assets tied together. Each part referencing a different "signal point". It just looks like a single signal ingame, becasue of how it is placed. So the combined signals shows "warning", instead of clear, followed by an immediate red. People need to realize that the assets are just a presentation layer of the signalling system, for us gamers, and even if all of them were removed, the signaling system would still work... alteast for the AI, we, the players, would have issues figuring the state of the next signal. It is also this underlaying signaling system the HUD is based on. So any extension of the HUD is most likely an extension of the system itself.
Not necessarily. In nearly all color-light UK routes, 200 yards before the distant the AWS will go off. So the AI is paying attention to them. And on German routes the AI that handles PZB is absolutely paying attention to the Vs. The issue rather is whether that information is being conveyed to the HUD
This is about track building, and they already add in markers for main signals (or those markers are part of the signal asset itself) so this isn't a difficult change I haven't checked but I'm sure someone will have. On SoS if you pass a distant signal which is at clear, does it go to caution when you pass? If so then the signal controls are caring about distant signals. Not sure if AI bothers with anything bar speed and direction controls, but then it's a cut down version of the physics and controls so take that as you will Agreed, but you're basically agreeing here that "it's more complex than go, slow down, stop" and that little dot can convey more than those three states with a few tweaks I'm not sure on this. Personally I would say it's got less functionality than it maybe could have given the complexity of the system(s) it's trying to represent
Soo, you can have distance to the AWS or PZB magnet, becasue those are placed on tracks. But the signal can be anywhere. Even simple things can be time consuming. If you need somebody to go through the route and mark appropriate distant signal location on track, it might not be difficult, but it surely isn't a quick job. If so, then it should indeed be possible to show the signal on HUD. Unless it is only for combined signals, and it is the asset logic (if main signal arm is down, also the distant has to be down) As a Dev, this is how I would do it, because it has clear separation of responsibilities and offers you great flexibility. The underlaying system that is opaque to the user does all the decision making and you then just add assets that change it's appearance based on state of an invisible signal point, which defines block boundary. This allows you i.e. taking a fully functioning british signalling system from i.e. London Commuter and using it on Brighton... and you only need to change the signals assets. You're also then fairly confident that changing a signalling asset will not cause regression in the signalling system proper. Also a wrongly set-up signalling asset will only affect that particular point, and only for the player. Basically, the only logic you want to tied to the asset is how to represent a singaling point state for the asset itself (i.e. if it is restricting 60km/h, show a 6 int the speed box). It also allows you to place the signal assets where-ever you want. Like beyond the junction, as in Arose line, or you can even have assets that are not signals at all, like a red board at an end of an unprotected siding.
Of course in perusing these discussions I should point out that although I drive with the distance to next signal displayed on the HUD, I don’t have it show the upcoming aspect as I regard that as a bit of a cheat. However I certainly think the HUD should register and show a distant signal upcoming so you can pop your head out and check its status. After that, it’s up to you the driver - if the distant is “on” then you need to follow the absolute block rules and expect any associated stop signal to be at danger - be that anything from an outer home to advanced section signal, where provided. I guess this again illustrates the difference between sim and reality. A real driver on the route will know off by heart where each signal is and the need to slow down immediately if you get a distant check. We are jumping in these trains and driving them like a car on a highway looking out for traffic lights, without necessarily any prior knowledge where we’re going. Perhaps new routes, especially those with manual signalling, need to include some sort of driver experience or training mode (would have to be optional) emulating the real world gaining route knowledge.
It would certainly have to be optional. We can't forget that the vast majority of TSW players are casual gamers who would have little interest in learning a route like a real- life driver nor would they want to study complicated signaling. They just want to get in the cab and drive a train, using the full array of HUD features.
Depending on the editor... it could be as simple as CTRL + H equivalency in word... Not saying it is; but it could be I think that's what I'm saying. If the first signal in a block is at caution because any subsequent signal in that block is at danger and it isn't the next signal then all signals on the HuD should be at caution until it either gets to the danger signal being next (when it changes to danger) or when that signal clears (when it changes to clear) I agree, but the block boundary doesn't seem to be correctly set on semaphore signals, or on the boundary of colour light and sempahore signals. IRL this would be managed by a signaller in a box local to the line and all the drivers would know the line and which signals need to be read how, but in game there are people who rely on the HUD signalling (ignoring lineside signalling) an if that HUD is only reading caution at the signal before a signal at danger, then this isn't how a lot of the old system works, where a single caution may cover several signals, so to my mind the HuD should reflect that caution the whole time, even if the next signal is reading as clear
In RailWorks, Distant signals had a track link just like any other signal; they needed that to probe the state of the signal(s) they depended on. They were just configured to be invisible on the "track knowledge" panel of the HUD, in the same way as AWS magnets etc (which also had track links but which the user would not perceive as "signals") were. It's entirely reasonable to assume that TSW does it the same way.
I’ve always thought that distant signals should be represented in the HUD as they play such an important role in driving a train on a route where they are present. The simplest form of showing them could be using the same icons as main signals but in a smaller size or with a border around them. The simple main signal (SPAD potential) icons are always shown as usual but distant signals could be shown in different ways for different systems as appropriate. For distant signals that relate to more than one signal ahead, surely an intelligent system could be developed where if one of those signals is at danger the HUD shows the icon for the distant signal and then the signal at danger and distance to it, disregarding any clear signals in between as far as showing them on the HUD. That’s more useful than showing no distant and the next main signal that may be clear but closely followed by a main signal at danger as it does now. A distant signal HUD icon for German or US signals for example may not be able to show all the configurations that a distant signal can show but it would be able to use the current yellow and green icons to show if the next signal is clear or at danger. The signals on Peninsula Corridor work okay for sequential signals with just a yellow aspect in the HUD and using the real signal to see which type of warning signal is, in the same way as single and double yellows show the same in the HUD for UK routes, and the real signal must be looked at to see which it is. The danger is that the more complicated the setup for each signal or signal block becomes the more chance there is of it not working correctly or prototypically, and the complexity of designing HUD behaviour for new signalling types that appear but important signals should not be left off the HUD as present. Apologies for any non-standard terminology used in this post.
Actually, and I may be thinking too simplistically here, but since all the distant signals are shown on the 2-d map, would it be very difficult to write the code needed to copy them to a modified HUD, depending on the position of any switches which would indicate the pre-set pathing? The next or approaching signal is clearly indicated on the map and HUD, so why not the next or distant signal? A smaller aspect could be used on the HUD for the distant signal.
I love how everyone's chiming in with assumptions that this is somehow "difficult" or "special", and proposing alternatives that would actually be more complex to implement (so far as I can see). And by "love" I of course mean something completely different… Making Distant signals appear in the HUD should simply be a matter of flipping a switch in whatever module implements those signals, so that they are presented as completely normal signals to the HUD - signals that simply happen to never show a Stop indication. It could also have been done in RailWorks, I'm sure, but it was less problematic in the older game since players were much more clearly encouraged to read the actual signals rather than relying on a HUD. Similarly, making combined Home/Distant signals show their Caution aspects in the HUD should simply be a matter of changing that module to reflect the combined aspect, rather than only the Home aspect, to the HUD. They are not separate signals in the game; you can tell that by the way the Vr head correctly goes blank when the Hp head mounted above it shows red. A very similar argument can be made for treating the "Slow" and "Expect Slow" aspects as Caution in the HUD. This should also have no effect whatsoever on AI traffic. This leaves my suggestion about consecutive Home signals. This would only require changing the modules associated with British semaphore signalling, which are only used on two routes so far (not counting Northern Trans-Pennine, which uses an early and rather broken attempt at it in places). This is therefore the correct time to do so. Again, since it is only changing the HUD indication from Clear to Caution in certain conditions, there should be no effect on AI traffic.
The more I think about this, the more I'm leaning towards the distant information - if it can be reflected in the HUD - (and that's an interesting if ) is best suited as a text based representation - because you would be driving to the information in rear, not the information in advance. Granted, there are some examples of signalling exotica that are unlikely to be covered by this sort of ruling such as APB and and/or MZA (Madrid-Zaragoza-Alicante) where there are multi-position distant signals or where there are accelerating distants. Mind, the accelerating distants are just about possible to appear on a DTG route sometime. Don't forget too that if there is a Western Region/GWR model there would need to be some means of reflecting Regulation 4A - Line Clear to Clearing Point only, which is tied in with the working of the distants. I think whatever happens for a "British" style semaphore - so a two or three position horizontally pivoted arm or MAS reading onto another two or three position horizontally pivoted arm [1] HUD the distinction needs to be made that it is still a speed signal and not a block signal - and some form of textual indication on the HUD to ensure that the information direction is distinctly different: you drive to what you have seen until you see another one. [1] French and Spanish mechanical "distants" would probably need HUD symbols of their very own, once you get into the territory of parada difidera, disque rouge et al.
This isn't how I understand the UK signalling, semaphore or otherwise. We don't have speed based signalling, all of it is informational and therefore in this instance if the first signal is cautionary, all subsequent signals within that section should be passed as if the next signal is at danger until you clear that section I understand this doesn't work for all other signal types in the UK or elsewhere but the HUD is supposed to be simplified. If you want to know what the last signal was telling you, you should have been paying attention.
Yes; yes you do: all British distants are a speed-based signal. Agreed with you completely, that you should remember a signal you have passed but a semaphore distant is not a block/occupation signal - it is purely a speed signal - and has ever been so since the distinction with auxiliaries/inner homes or auxiliaries/distant in the later part of the 1860s. A UK distant is a speed signal.
A UK semaphore distant signal at danger is a prepare to stop signal until the next clear Distant signal is reached..
You are definitely overcomplicating this. The HUD provides a deliberately simplified representation of the next signal ahead, for the benefit of novice players. The information it provides is a distinction between: Green: The line is essentially clear ahead. Yellow: There is some restriction ahead, but proceeding past this signal is authorised. Red: You must stop at this signal. I argue that there should also be a distinction between "there is some restriction ahead, but at least the next block is free of outright obstruction" and "proceed on sight into the next block, which may have a train in it already". The latter would be used for shunt signals to distinguish them from main signals at Caution. But that is the only further complication required for the HUD - no matter how complicated the underlying signalling system is. Players wanting to handle the full complexity can read the actual signals. The fundamental problem, however, is that presently the HUD does not actually provide the above basic information to the player in certain cases. These cases are: Distant signals which are missing entirely from the HUD, combined Home/Distant signals which provide only the Home (Red/Green) information in the HUD, and Home signals that are not also section signals, which (so far as the HUD is concerned) should be treated as Caution signals when the section signal in-advance is still at Danger, but which presently give players false reassurance of a clear line ahead. Address that problem first.
Agreed - this is how every reference I've ever seen treats them. They are fundamentally elements of a block system, and convey no explicit speed limit to drivers - which is what is commonly meant by "speed signalling". The driver must simply control the speed of his train so as to be able to stop at the relevant Home signals, which is a matter for what is now called "defensive driving policy".
No, this is completely wrong. A British distant signal conveys absolutely no information or orders about what speed a train should be driven at. All it does is caution the driver that an upcoming stop signal is at stop. It is entirely up to the driver, using their knowledge of the route, to determine how the speed of the train should change in response to this information.
I think it would be quite difficult to do that - if I've understood your post, you're wanting to squeeze the indications of the semaphores into a multiple-aspect heirarchy? There are several reasons that would make this difficult: there are two types of semaphore signal links "main" and "ancillary". Main links are for stop arms and ancillary links are for distants. When a route is signalled the process broadly is: Site all your main links - in the right geolocation. Site all your ancillary links where you want them. You then do a bit of black computer magic that hooks the main links to the track. Next stage is sorting out the routing, so disabling routes that you know won't work/be used and thinking up names/letters for those routes that will be used. Then visuals: so getting the heads to work by associating the route names/letters in the behaviour. Once that is done, then you can think about the distants. Each distant will have a sequential list through station limits of: the hex (or whatever flavour of base numbering) reference for each main signal link that is needed to be clear for the distant to clear. the route reference for each main signal link that is needed to be clear for the distant to clear In every case where there are junctions this will cover multiple chains through station limits (so the entire transit from outermost distant to advanced starter) - so each hex reference of the signals it applies to and matched up with the route - you have the same hex reference for each main link, but an additional reference for each route possible from that link. Ancillary links are not associated with the track in the same way as main signal links - you can alter them without causing any ill effect; however once the bit of computer magic that hooks the main links to the track then they're fixed (as it sets the possible routes from that main link) - if you need to alter a main link, then you need to make a note of all the signals whose routing tables will change if a main link alters and repeat the bit of computer magic to relink the main links to the track - depending on the routing any number of signals can be affected: if their routing is dependent on the altered link. Main links drive the HUD - so for a multiple aspect signalling set up, it is quite straightforward to have [RED], [YELLOW] (not-red, but also not-green) and [GREEN] (not-red, but also not-yellow) - yet for semaphores you have a mix of both main and ancillary links driving the visual information of the signal arms. So, either the ancillary links need to link into the HUD, or Rule 39A is implemented, or the rule of "if you see a distant at caution, expect any signal arm to be at danger until you see another distant". Both "getting ancillary links to link into the HUD" and "implementing Rule 39A" are not easy tasks - as I've said elsewhere, we are thinking/considering Rule 39A - but it needs each and every signal on the main lines to be appraised - particularly (but not exclusively) the approach speed, the approach gradient and the sighting of the signal, let alone the siting of the signal. So at the moment - while there is thought going on in the background of how to achieve these things, the safest and most consistent approach at the moment is that outlined above: "If you see a distant at caution, expect any signal arm to be at danger until you see another distant" ...and that is *exactly* what I mean by a UK distant signal being a speed signal. [1] They convey no block occupancy information, and as a signalling historian I know the path from deferred stop/auxiliary/distant - any semaphore distant is the last vestige of the old three-position time interval system. One of my areas of expertise outwith DTG is the change in signalling ethos during the very, very short period of 1862-1872 which covered the transition from time interval to space interval (block); moreover one of the other strings to my bow is the adaptation and implementation of UK signalling of that period into other countries - particularly within the lusophone/hispanophone/francophone spheres - each of which preserve, in fragment, the original kernel of the UK operating practices - it is exceptionally interesting to read the untranslated texts when new signals were introduced and you can divine a path back to the UK speed distant. [1] in the 5 graduations between "Speed" and "Route" signalling [Strong Speed] [Strong Speed, Weak Route] [Route and Speed Equal] [Strong Route, Weak Speed] [Strong Route] - the UK is a [Strong Route, Weak Speed] due to the use of splitting distants, both semaphore and MAS.
I'm sorry, this is just gibberish as far as I can tell. How are splitting distants related to speed signalling? Have you just made up "the 5 graduations between "Speed" and "Route" signalling"?
I strongly suggest you read various IRSE papers on the subject, particularly those concerning the introduction of the fourth aspect into UK signalling as well as remembering that a semaphore distant signal conveys no block occupancy information whatsoever - like it or not, it is a speed signal. It certainly isn't a block signal, is it? Moreover, the papers of Acfield and Bound (MR/LMS) as well as Maj. Morkill (Met.R) exercised much thought about distants and the indication of expected speed to Drivers - granted I don't know how much time you've spent studying and researching signalling history and operating evolution, but conceptually a UK distant is a speed signal.
The usual distinction between signalling methods is speed vs route, not speed vs block (pretty much all speed signalling systems use blocks). These tend to be ill-defined terms, but a signal that provides information of an upcoming signal aspect without imposing any speed limit is generally not considered a speed limit. Are you taking the position that any signal aspect between "all clear" and "stop" is a speed signal?
The distinction is in the intent of providing information to the driver - and there are crossovers between pure route and pure speed; hence the five graduations above. My distinction is that a UK semaphore distant does not convey any indication of stop/go, no indication of block occupancy ahead and acts as an "informer" to the driver of the potential speed ahead. Perhaps, once I can dig out the relevant information (may be a couple of days) it would be worth considering the "accelerating distants" installed on the LNER - again precisely the same as an ordinary distant in appearance, and has the same import to the driver - carry on at booked speed if "off" (or in the case of the accelerating installation, start winding up the go juice) or exercise caution - a snippet of information pertaining to speed. Expressly the expected speed ahead (though, not a specific speed) - the transition between speed and route signalling took a long time of evolution before aspects developed specfic speed bands - and even now, identical indications can mean different end speeds in a speed signalling installation. I can't take the position that "any signal aspect between all clear and stop" is a speed signal, because it entirely depends on the signalling system in force, even to the shape of the signal let alone the number of aspects or combinations. As I've said before, a UK semaphore distant is a signal indicating expected speed ahead to a Driver - it is a speed signal dating from before "pure" speed signalling systems were adopted - as a related aside, the Indian adoption of the distant (always in conjunction with a stop arm) is called a "Warner".
I'm sorry, what do you think a distant signal indicates if not the position of upcoming stop signals?
The function of a Distant signal - whether the UK or German type - is to effectively extend the sighting distance of the Home signals to which it refers. This became necessary as soon as the braking distance of trains began to exceed the all-weather sighting distance of signals. The message the Distant signal at Caution conveys to the driver is therefore: reduce the braking distance of your train to the sighting distance of the Home signals ahead. This is indirectly related to speed, and in modern trains is mostly accomplished solely by slowing down - but in earlier trains with more primitive power and braking systems, it might simply have prompted the driver to shut off steam, gather the train to reduce buffer shocks, and alert the brakemen throughout the train to expect an impending braking operation. That might all take long enough for the Home signal to come into view. The Distant signal does not, therefore, instruct trains to maintain any particular speed. It instructs them to expect to stop. That is inherently part of a block signalling system, not necessarily a speed signalling system. We can compare this to the German system. This also uses distinct Distant signals. But these can show "expect stop" and "expect slow" as well as "expect clear". The "expect slow" aspect, and the "proceed slow" aspect of the corresponding main signal, is characteristic of a speed-signalling system.
That's not how a UK semaphore distant works - the meaning can quite legitimately include a route for which all stop signals are "off" through station limits, but there is still a need for caution: such as changing from slow to fast or entering a goods loop. It is mistaken to assume that a UK semaphore signal merely repeats the combined stop arms in advance of it.
The use of time-interval block was a causal factor (though far from the only one) in the 1889 Armagh disaster, well after the "very short" period you quote - and at the time the whole of Ireland was part of the UK, thus subject to its railway regulations. It was this tragedy that prompted the Railways Act 1892; the so-called "Lock, Block & Brake Regulations". It was only this that finally eliminated time-interval block from British railways. I am also finding references stating that Rule 39a was already a feature of the 1933 RCH signalling regulations, and possibly this was inherited from a majority of pre-Grouping rulebooks, with an equivalent rule still being in force today. I would be interested in seeing definite, documentary confirmation that Rule 39a is present or absent in each of the 1933 RCH, 1950 BR, 1960s BR amendments, and maybe also 1970s/80s equivalents (where I understand the rule numbering system was changed). Implementing Rule 39a, or at least some approximation to it, would already make the HUD behave much more sensibly for UK semaphores, even if it doesn't point out Distants. Even so, I regard omitting Distant signals from the HUD as a serious mistake. Your background may be in signalling history, but mine is in software engineering. This sounds very much as though some unfortunate design decisions were made which are now, and entirely foreseeably, making your life much more difficult than it needs to be. The mismatch between RailWorks' signalling model and UK semaphore signalling practice has been evident from practically the beginning of RailWorks' history, so this should not have been overlooked when introducing TSW. My suggestion in this area is to recognise that, unlike German Vr signals and modern use of colour-light Distants in TCB territory, semaphore Distants are not repeaters. They each have their own lever in the box which must be pulled to clear them. Repeaters, as the name suggests, depend solely on the aspect of some other signal, and do not require separate actuation. Hence, it may actually make sense to implement AB Distants (whether semaphore arms or colour-light substitutes) using "main links" instead of "auxiliary links" to the track. This would both make it easy to display them in the HUD, and also probably ease implementing Rule 39a as follows: Section signals are easily distinguished as either carrying a Distant arm on the same post (in which case they may exhibit Danger, Caution, or Clear aspects) or being followed in-advance by a Distant signal (thus observing only Clear and Caution aspects from it). Home signals that are not section signals are easily distinguished as either observing a Home signal in-advance (only Clear and Danger aspects) or a buffer stop. Distant signals need only observe the signal in-advance as normal, exhibiting Clear and Caution aspects. Home signals observing a Clear or Caution aspect in-advance, as well as a suitable confirmation of the section being clear, may themselves clear immediately. Home signals observing a Danger aspect in-advance must exhibit a Danger aspect themselves, until approached closely and slowly by a train in-rear, and with the section to the next Danger signal being clear. This is Rule 39a.
I have been very careful to make it quite clear that a distant "on" does not intimate a specific speed; it does however intimate a need for caution not exclusively "expect to stop". I realise that for some participants in this discussion there is a steadfast unwillingness to accept that a UK semaphore distant is a speed signal: all I can say to you is look at the evolution of the distant, consider the placing and usage of fixed distants and to whom that information is directed. There is a lot of discussion within IRSE signalling papers about the speed function of distants and I'm going with the IRSE. It is conceptually a speed signal. Yes, it can be many other things, but it has no block function, it cannot stop a train but it is used to regulate the speed of a train from the moment it is sighted until the train either passes through station limits or encounters another distant.
I used to drive with the aspect off back in the days when signals were easily seen in TSW. Now there are far too many instances where I have no chance of telling what aspect a signal is until it is too late. On BCC, there are many cases where you can’t even see that there is a signal there let alone what aspect it is showing. The HUD is the only hope of telling the aspect in time to drive accordingly.
