Lirr Speed Limits

Discussion in 'TSW General Discussion' started by solicitr, May 11, 2021.

  1. solicitr

    solicitr Well-Known Member

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    Could somebody please explain where LIRR hides its speed limits? I don't mean the in-cab traffic-speed system, I mean the hard track limits (no, they aren't lurking in the signals, either: all I get are Proceed Clear). I haven't seen a single speedboard anywhere.
     
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  2. geloxo

    geloxo Well-Known Member

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    There are only 4 speed boards in the whole line. The rest you need to know them by heart or to use a track layout with them while driving. It seems that´s also the case in the real line. For that reason I prepared a map to help us driving there:

    Lirr Track Speed Restrictions Map | Dovetail Games Forums

    If you use my dispatcher radio tool the file is already included in the extras.zip file, so you can load it using the Route Map tab.

    Cheers
     
    Last edited: May 11, 2021
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  3. solicitr

    solicitr Well-Known Member

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    That's bullcrap. I always hated this stupid route, and I refuse to drive under Magic Speed Limits cast by an invisible wizard.
     
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  4. tallboy7648

    tallboy7648 Well-Known Member

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    Well there are speed limit signs all over the route/railroad in real life. It's just that when dtg made the route at the time, they didn't put the speed limit signs in for some odd reason
     
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  5. geloxo

    geloxo Well-Known Member

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    You wanted realism? This is one of the most hardcore routes to drive. ATC is just a MAS (max authorized speed supervision) and there are no speed boards. Welcome to hell! :D

    Cheers
     
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  6. solicitr

    solicitr Well-Known Member

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    I also notice that in the scenario Change at Jamaica, the signals happily give me a Proceed Clear (at 80 mph) when entering a block occupied by a train stopped at the station!!!!


    Don't talk to me about 'realism' Whatever else Adam's team did, they certainly didn't fix the totally borked signaling.
     
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  7. tallboy7648

    tallboy7648 Well-Known Member

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    Yeh that wouldn't happen in reality. If there was a train ahead, it would not have given you that 80. The ATC system is broken. Hopefully the atc system will be fixed eventually
     
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  8. solicitr

    solicitr Well-Known Member

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    And the signal would have been a hard Stop, or at most a Stop and Proceed. Certainly not a Proceed Clear!
     
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  9. geloxo

    geloxo Well-Known Member

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    I don´t know the case of that scenario you are referring but signal does not appear correct. Anyway remember LIRR ATC just gives the max authorized speed for the block and that´s what it supervises, nothing else. It´s not an ATP like LZB/PZB, so it´s not intented to protect train movements, but just to supervise allowed block speeds. You still need to follow signal indications while using it. Therefore they won´t fix it because it´s not broken indeed, unless there are mismatches in the speed limits mapping from the track to the onboard system in game.

    Cheers
     
    Last edited: May 11, 2021
  10. tallboy7648

    tallboy7648 Well-Known Member

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    Indeed but unfortunately that is not simulated in the m3 or m7. If you look closely at all the numbers 15,30 80 etc, at the bottom there is a square that says stop which would inform the operator to stop the train because of a train ahead. They would have to clear the alarm and stop the train but it isn't simulated in the game which is one of the reasons why we have incorrect timetables on the Ronkonkoma and Hempstead Branches (the two lines that are in the game. Belmont Park Services are part of the Hempstead Branch). If dtg were to include extra services you would literally have AI stop 2 inches from one another and a player would get a 15 mph warning but not a alert to stop the train so a player could crash the train into the train ahead if they don't see it and derail. I really hope Adam's team fixes the signaling or maybe someone from the main team can fix it
     
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  11. solicitr

    solicitr Well-Known Member

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    You're missing my point. The trackside signal guarding the block entrance reads Proceed Clear. Not Stop. Not Stop and Proceed (which can happen). Not Restricting, or even Slow Approach: Proceed Clear.
     
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  12. solicitr

    solicitr Well-Known Member

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    Again, I'm talking about the track signal, not the in-cab. Three lights in a vertical line: proceed at MAS. Smack into the stopped train.
     
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  13. geloxo

    geloxo Well-Known Member

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    Yeah, yeah, I was just editing the answer. The signal shall not give a proceed with a train ahead the block. That´s an error for sure :)

    Cheers
     
  14. tallboy7648

    tallboy7648 Well-Known Member

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    Ohh yes yes I see. I had a similar issue with that. The hud will have a green aspect and the physical track signal will be green yet there will be a train ahead which is definitely a glitch. Don't get why that wasn't fixed although the in cab signaling in reality as well would inform the driver to stop the train if there is a train ahead which sadly isn't simulated
     
  15. mclitke

    mclitke Well-Known Member

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    I heard once on a live stream from Matt that on LIRR the drivers would actually have to operate with line of sight, which is also why apparently when a train leaves Jamaica the next comes swooping in right away. Is that true? While surely nowhere near intended it might not be that far from reality after all. Would a physical signal still block the next section?
     
  16. tallboy7648

    tallboy7648 Well-Known Member

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    A physical signal would do that indeed and the In cab singaling would inform the driver to not proceed as well (STOP)
     
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  17. Mattty May

    Mattty May Guest

    The signalling, speed limit markers and whistle boards leave a lot to be desired on LIRR. I love the route, but a lot more love needs to go her way.
     
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  18. Dinosbacsi

    Dinosbacsi Well-Known Member

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    Well, that's how it works on LIRR in real life as well. Not magic speed limits cast by an invisible wizard, but route knowledge of the drivers.

    As for the ATC system, it's horrible and bugged, yes. But sadly that didn't get fixed this time and they honestly admitted that. But fingers crossed it will be in the future.
     
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  19. geloxo

    geloxo Well-Known Member

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    The point with this system, and the confussion with LIRR route in general, is that its onboard it´s not an ACSES, but an ASC system. ACSES is the one used in NEC corridor and it´s much more complete in terms of provided supervision. In LIRR the ACSES system was scheduled to be in service around 2019 or something like that (later than the DLC was released) so game reflects the situation prior to ACSES start of service, even if the onboard console already has the ACSES power indicator and track speed indication area modelled in the M7/M3 units in game, as it was the case in real trains as well in preparation for the start of service of that system later on. But when you enable safety systems in game only the ATC (the ASC) is enabled.

    Some of the main diferences between the two of them is that ACSES replicates the signal aspect in cab, also supervises the stop aspect and knows all speed limits from the line (including speed restrictions from boards). On the other hand ASC just replicates the block speed limit in cab, supervises a 15mph speed limit in the case of the approach to a stop (but it does not brake train in case of overpassing stop signal) and only knows the max speed limit of the block your train is located at, not the one from the block ahead of you and also not each single speed limit inside the block. That´s why quite frequently both HUD and ATC speeds are different because HUD displays the most restrictive speed limit you are facing at each location. The ATC limit can change with signals aspects, yes, but you can´t expect it to display the speed restriction of a curve like the one at the entry to Jamaica because this limit is simply not known by the system.

    Both are systems working using the coded speed limits philosophy to translate signal aspects into speed limits in cab but they are not exactly the same thing and definitely they are not the same as more advanced ATP systems like LZB which are able to supervise speed limits dynamically based on braking curves which are updated with the traffic ahead of train.

    You can take a look here to know about those systems:

    Pulse code cab signaling - Wikipedia
    Automatic train control - Wikipedia
    Advanced Civil Speed Enforcement System - Wikipedia

    Cheers
     
    Last edited: May 11, 2021
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  20. solicitr

    solicitr Well-Known Member

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    Not at all. Frequently the ATC is reading 15 or 20 where the HUD says 40.
     
  21. solicitr

    solicitr Well-Known Member

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    Yes, I understand how it is supposed to work. The thing is, the TSW model of it does NOT work that way. In fact, doesn't work at all.

    More driving, and I can confirm the ATC does NOT work at all; I just blew through an Approach Slow and it is still happily telling me 80 mph.
     
    Last edited: May 12, 2021
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  22. solicitr

    solicitr Well-Known Member

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    What the heck is this? The Bronze Age? The UK? Any system which relies on driver memorization is hopelessly primitive and ought to be illegal. Amazing that New York- smug, superior, supercilious New York- would use such a backwards model.
     
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  23. solicitr

    solicitr Well-Known Member

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    When operating trains practically nose to tail -as they do during peak hours- the station blocks are protected by Stop-and-Proceed signals: full stop, then proceed at not more than 15mph prepared to stop in 1/2 visual distance. This allows them to have one train pull up to a platform immediately after the preceding one leaves.
     
  24. sinnere

    sinnere Active Member

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    During rush hour it is common to see another train trailing another a car length or less away at Jamaica. Here's a vid I took two summers ago. This can be done anywhere in the system.
     
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  25. cwf.green

    cwf.green Well-Known Member

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    I don't know how it works IRL but I agree with you that a system that requires drivers memorizing speed limits and their locations is incredibly vulnerable to human error.
     
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  26. Mattty May

    Mattty May Guest

    The fact is, there are videos on YT that show speed signs and whistle boards. There are a couple in game, but many more are needed.
     
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  27. tallboy7648

    tallboy7648 Well-Known Member

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    I wonder why dtg didn't include them in the route to begin with
     
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  28. geloxo

    geloxo Well-Known Member

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    It's the same risk that you have in a route like NTP as the speed boards are not visible during night for instance. Even at LIRR itself you have no protection against SPADs as the system does not brake train so safety relies on driver in most cases. The danger is not in the initial risk you have but in the resulting risk after the mitigations you applied to reduce it. In most cases operational rules are applied to deal with them and they are considered enough even in cases where no protection system exists at all like in sand patch route (alerter does not supervise signal aspects nor speed limits).

    Cheers
     
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  29. Ravi

    Ravi Well-Known Member

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    I just want to thank you for that amazing file of information you have put together. It is now my first go to for any information I need before I got to google. Thank you for that. o7
     
  30. solicitr

    solicitr Well-Known Member

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    That's not much of a defense: "It's just like a dangerously unsafe system from half a century ago."

    Not having PTC does not justify unsigned speed limits. It's one thing to rely on the driver to react correctly to cues, and quite another not to give him any.

    Moreover, as tallboy7648 (who knows the LIRR) has pointed out, in real life it does have speedboards; DTG simply couldn't be bothered to put them in.
     
    Last edited: May 12, 2021
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  31. tallboy7648

    tallboy7648 Well-Known Member

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    I believe that they weren´t given access to the railroad when it was made at the time. But even then there are videos and images of speed limit signs along both lines in real life so I wonder why they didn´t add them in. Perhaps they can add them in in a future update
     
  32. driverwoods#1787

    driverwoods#1787 Well-Known Member

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    One more thing that the game needs to reflect is the speed at Queens interlocking which is visible at Floral Park Station its actually 80 mph 130 km/h instead of 15 miles per hour (25 km/h) to 30 mph (50 km/h) in game for a Ronkonkoma Branch service. Post-pandemic perhaps the entire development team needs to go to that location in order to fix the speed limit for those switches
    Video is by Jersey Mike's Rail Videos on the proper Queens interlocking speed
     
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  33. geloxo

    geloxo Well-Known Member

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    But this is not how risks are managed in railways. For instance a token system is an ancient solution which is still extremely safe for many modern railways operation because it´s impossible that two drivers own the token at the same time. In other cases collision risks caused by drivers overriding red signals is mitigated by leaving some blocks free between trains (operational rule). I could even tell you examples of high speed lines being operated in the early stages (until systems like ERTMS were in service) using voice track warrants and systems which are not SIL4 (the safest). Human factor will be always there and it´s one of the biggest risk factor you have to deal with. But remember that it´s not all about the risk but the mitigations you applied to reduce it and the consequences of the risk itself. For instance more people can be potentially injured if a train loaded with chemicals crashes at a station in a city than if two commuter trains crash at the same station, and most of the freight trains are not yet operated using ATP systems at all, but with signals or just track warrants in some cases, which are other examples of ancient solutions but still safe for many railways.

    Cheers
     
    Last edited: May 12, 2021
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  34. Dinosbacsi

    Dinosbacsi Well-Known Member

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    There are a bit more speed limit boards in real life than in game, yes. But there are many unmarked speed limit changes in real life as well. It's just strange.
     
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  35. Anthony Pecoraro

    Anthony Pecoraro Well-Known Member

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    Not every speed change on LIRR has boards.
     
  36. solicitr

    solicitr Well-Known Member

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    Which I find bizarre. In Germany even LZB trackage still has speedboards. On LIRR in the game it is far worse than that, because ATC is hopelessly broken and can't be relied on at all. (Then there's the notorious "accelerate to 60 -PSYCH! 30 in 100 yards" trap. With NO Medium Clear signal).
     
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  37. Dinosbacsi

    Dinosbacsi Well-Known Member

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    It's bizarre and annoying, that's for sure, but that's how it is. I believe many lines on the New York subway don't have properly placed speed limit boards either - don't quote me on that though.

    Well the speed limit changes don't have much to do with the bad ATC, as the track speed limit and the ATC speed limit would very often be different even with a properly working ATC as well. But the rule is simple - always drive by whichever is the lowest of the two.

    But I do wish they would fix the damn ATC... And I'm still waiting for my whistle boards as well. They even noted it up in one of the stream months ago.
     
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  38. geloxo

    geloxo Well-Known Member

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    Remember that even if ATC updates to lower limit instantly you are not expected to be prepared in advance for that speed limit, mainly because you have no way to know about any changes as ATC does not include any target speed announcement feature like LZB or TVM have. For that purpose the ATC includes the braking supervision, which is indeed the main safety protection this system offers in addition to the max speed supervision itself. You just need to reduce to the current ATC limit with a proper min deceleration and keep that deceleration until you are below the new limit in force. You have to use signals to anticipate to potential speed reductions as normally ATC updates at the signals, but it can also update between signals if additional blocks exist there. But even signals update according to traffic ahead so ATC can also update if the signal conditions change.

    Don´t see this system as a real train protection system as it´s not an ATP. It just supervises max allowed block speeds. See it as an aid for driving with some speed supervision, as that´s all it does indeed. The real safety behind this ATC is that it ensures you will brake enough to reach the given limits in force for ATC, no matter if you take ages to do that or you do it faster, but at least you will do it within the safety margins of a min deceleration value or the system will brake train. That minimum deceleration value (the one linked to the ATC forestall indication) is the one taken into account to know how much distance trains will run before reducing speed and it´s the one considered by operators to evaluate the possible hazards. Indeed ACSES, being a more precise system in terms of knowing all speed restrictions inside the blocks, works under the same minimum deceleration principle and can produce sudden speed reductions as well as ASC does.

    But this behaviour is what you will see as well on other systems like PZB, as you can be running at max speed with a proceed aspect and face a sudden yellow aspect that forces you to reduce to 85, 70 or 55 without any prior warning. PZB does a similar supervision, but instead of monitoring deceleration it monitors time to reach a target speed so that you brake enough to reach the 1000Hz magnets speed limit. If not PZB will also brake train the same way ASC does. Indeed both things (ASC deceleration supervision and PZB time/speed supervision) are the same concept and that driven distance during braking is the one considered in the tracks engineering to decide signals, magnets/balises and speed limits announcements spacing so that speed limits are always met in a safe way.

    Cheers
     
    Last edited: May 13, 2021
  39. solicitr

    solicitr Well-Known Member

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    However, PZB is designed to account for braking distance; with 1-1.2 km between Vs and Hs, one can get down even from 160 km/h albeit with hard braking.

    Whereas on LIRR, like on old UK routes, one is often stuck with reductions which are physically impossible, at least if one relies on the signal and signage system.
     
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  40. geloxo

    geloxo Well-Known Member

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    Deceleration supervision is indeed a braking distance supervision too. Imagine that LIRR longest train (12 cars) takes, let´s say 1000 yards to stop. As you know that no longer train that that will be authorized to run there during your track design you may need to use blocks with a min lenght of 1200 yards bacause that´s the max braking distance of your longest train (worse braking case) plus a 20% safety margin for instance. It doesn´t matter if it passes a yellow at 80mph, because anyway it will brake before the next signal if all blocks are using at least a 1200 yards lenght. In real life many times you need to adapt blocks to evolution of traffic and headways. If 25 years after line service started you have more commuter trains you may need to shorten blocks and/or reduce speed limits to allow more trains to run closer to each other in the vicinity of stations, or increase distance if you put high speed trains (that take longer to brake) or even move signals to allow longer trains to fit into platforms. If at one location it´s impossible to brake enough and it´s impossible to move signals as well then you need an operational rule and add a speed restriction there, even if it´s not required because there´s not a curve or something like that there. In most cases this also leads to the need to update lines to work with an ATP system or any kind of protection that reduces the hazards inherited by increased capacity or mixed traffic. All railways have their own engineering rules which are linked to their safety analysis and they are also updated over time as traffic conditions are also changing quite fast over time to meet the railway demand.

    Cheers
     
    Last edited: May 13, 2021
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  41. solicitr

    solicitr Well-Known Member

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    Yes. But what actually happens is that you are expected to brake from 60 to 30 in 100 yards- without warning. Not even a (fairly useless) Medium Clear, because the in-game signaling is screwed up. This has nothing to do with block signaling, but track-limit signals (something which CSX has no problem implementing correctly)
     
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  42. geloxo

    geloxo Well-Known Member

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    But that´s because signals are usually not giving you any announcements for track speed limits but for limits related to signaling conditions only (basically speed reductions produced by approach to yellows/reds or reductions related to pass over switches in diverging routes). You have some aspects that act as advanced warnings for what will be a further speed reduction but even them are not speed announcements themselves. They are just the consequence of the signals sequence. CSX signals are also not giving you any speed reductions related to speed limits on the line. For those permanent limits you have the speed boards. What can happen usually is that boards and signals aspects may match in position. For instance at the entry to a yard you can have a switch and a speed board to the yard both limited to 15mph but signals will be announcing the switch, not the speed board itself, basically because interlocking has no idea about the track speed limits and only sees the signals changes. So as we talked before: if you have a proceed and the routes ahead you change due to traffic you may face a sudden yellow without time to react. What you won´t have ever is a stop after a proceed without a yellow in between, unless the signal itself had a lamp failure and forces it to display the most restricte aspect. But sudden yellows are really frequent. Be prepared for the rush hour DLC :D

    Cheers
     
    Last edited: May 13, 2021
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  43. solicitr

    solicitr Well-Known Member

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    Um, no. Any US system that uses a derivative of the old Pennsylvania/New York Central signal system (like LIRR and Conrail) definitely signals speed. It's in fact as comprehensive as PZB, except without feedback/enforcement: the amount of information conveyed is just about the same.
     
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  44. geloxo

    geloxo Well-Known Member

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    All railways are based on the same thing, and it only sees and knows about signal status and routes that involve those signals, not about speed limits. The rules the railways adapt for driving are the consequence of the signalling type they use. For instance they can link an aspect related to passing a switch at 15mph because all switches in the line are designed to be passed as 15mph in yards and another speed limit to 50mph to another aspect because you have a sequence of two switches, being the first limited to 50mph per design as is one located in main line and not in a yard, and all switches in main line will be then designed to be passed at 50mph. Interlocking (and therefore signal aspects) will just know that the route involves two switches, not the speed limit related of each of them. So it won´t adapt signals aspects to match those speed limits. In some exceptions you can design the interlocking logic to allow only some types of routes and match a special situation producing an artificial signal aspect that is linked in the driving rules to a defined speed limit (for instance an exit route from a station always giving a restrictive aspect instead of a pure proceed), but those are tricks used to deal with the limitations on the systems.

    A exception are the light boards in the german signals or any signals using that principle, as they can give multiple speed limits for the same signal depending on which route is set involving that signal. But even in that case the aspect of the signal is just the result of the sequence of signals ahead of it. The boards themselves will be the only ones coded to produce one speed limit or the other depending on which route is set in the interlocking, and this is always the same limit for each of those routes.

    In other cases like in high speed lines you can indeed link each switch or track location to a specific speed limit, as you may have multiple types of switches in the line for instance. But this information is given to train using the so called track profile, which is the one used by LZB or ERTMS. This information is linked to each route you set in the interlocking and generated by complementary systems like the balises or the trackside LZB so even in that case the interloking still only knows about the signals aspects in the route which is set not about the speed limits inside that route.

    If you are curious about how it works you can take a look here as it´s not a too technical explanation but still very interesting:

    Interlocking - Wikipedia

    Cheers
     
    Last edited: May 13, 2021
  45. Dinosbacsi

    Dinosbacsi Well-Known Member

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    They do signal speed, yes, but as geloxo said as well, on LIRR the ATC will not show the actual track speed limit. It will show you "there are no trains in front of you, so you could go this fast, if the track speed limit allowed you", which is why sometimes it will show a 60 in a 30 track limit section, etc.

    I don't get your issue. I mean yeah, the ATC is bugged as hell currently, but it's basics are not incorrect.
     
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  46. geloxo

    geloxo Well-Known Member

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    That's it. But on top of that the key is that signals are not used to announce speed restrictions. They can only announce the status of the track ahead (if blocks are free/occupied or if you have a diverging route or not) because this is what the interlocking knows. If any railway links a particular speed limit to any signal aspect that's normally just a driving rule because in most cases drivers will face a similar speed limit everytime they face that aspect (for instance when passing over switches). But this is not meaning that signals will adapt dynamically to the line speed restrictions to show aspects which are the result of that speed restriction instead of the result of the signals sequence ahead. This is not how interlokings work. Maybe there are exceptions in some railways or exotic situations, sure, but the general rule is identical in most railways worldwide as most of them use interlokings as their core, and at the same time interlocking is the basis too for most types of signalling systems, from the most simple mechanical signals ones up to the most complex modern ATP solutions.

    LIRR also works with an interlocking as core to manage signals/routes but it happens to use a coded speed limits system on top of it (its ATC). It just tells you that according to signal aspects you could drive as fast as X in that portion of the track if nothing else prevents you to reach that limit. But as soon as any other limit is more restrictive then you have to ignore the ATC one and follow the lowest applicable one. In that situation is where ACSES is really needed and that's the reason why normally you should see both ATC + ACSES together like in NEC route and not an ATC alone, specially if you don't have speed boards or any visual indications to support drivers. But anyway an ATC solution alone or anything based on coded speeds linked to signals aspects is still good for many railway scenarios.

    Cheers
     
    Last edited: May 13, 2021
  47. solicitr

    solicitr Well-Known Member

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    Well, that isn't conceptually very different from PZB (setting aside the latter's disciplinary aspect), which also has set speed limits for particular track conditions: green/yellow means 40 kph, because German line switches are engineered for 40 kph. It's true that traditional eastern US signals don't have an analogue to ZS3s, and so aren't as flexible, but nonetheless the system is designed to impart two sets of information to the engineer: block occupancy, though color, the traditional GYR sequence; and speed, by position.

    Where one has, say, a mainline switch of the 30mph class, then the protecting signal, when it is set straight ahead, will display G-R or G-R-R, or Proceed Clear: the green light indicating a clear track for the next two blocks, and its topmost position indicating proceed, or line speed. If the switch is moved, then the signal will change to R-G or R-G-R, Medium Clear: still clear in terms of block occupancy, but the middle position requiring medium speed, 30 mph. In a proper interlocking the preceding signal will have changed to Y-G or Y-G-R, Approach Medium, in other words prepare to slow to 30 mph by the next signal, the upper yellow here serving as a caution indicator and the middle green acting as a Vs.

    Needless to say, the LIRR model in TSW doesn't do this (although SPG does).
     
    Last edited: May 14, 2021
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  48. solicitr

    solicitr Well-Known Member

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    Yes, I understand that; but currently (game) ATC will happily send you at 80 right into an occupied block and smack into a stopped train. At other times it will hold you to 15mph for no reason whatsoever.
     
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  49. geloxo

    geloxo Well-Known Member

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    Those 80s before a stop aspect appear to be bugs. You should normally expect 15s in that case. Anyway, as driver, you must always follow the most restrictive speed indications from all available. Same as if you had a track works area with temporary speed restrictions or flags in place. They won't be known by the ATC but you should still follow them.

    Cheers
     
  50. solicitr

    solicitr Well-Known Member

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    Well, of course. But at that point line speed was also 80 mph.
     

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