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Ntp Leeds-manchester Bug

Discussion in 'Technical Reports' started by GingerNinja2343, Mar 29, 2020.

  1. GingerNinja2343

    GingerNinja2343 New Member

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    I’m playing on NTP and I’m doing the locomotive driver journey. When I try to drive on the Leeds-Manchester Victoria service (the service above rescue run) about 5 minutes after leaving Leeds I get a ‘Scenario failed: Signal passed at danger’ every-time I attempt the route, even though I am not over speeding or passing a red signal. I’m on xbox one.
     
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  2. Trim

    Trim Active Member

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    Aha! I just happen to have played that very same journey on PC this morning and had the same thing happen. I wasn't particularly paying attention since I was concentrating on speed at the time (it was very close to where the speed changes from 25 to 60), and I have the next signal aspect of the HUD turned off, so I thought I could conceivably have encountered a red. However, it seemed a very odd location to be stopped (it is still a very long way from MorIey, the first station) and I was very surprised to have also missed the preceding yellow(s), apart from which, even when I am not particularly concentrating on signals, I find that red main signals tend to instantly grab my attention.

    I simply did a restart, carefully watching each signal (and going a little faster out of Leeds, as it happened), and this time they were all green till Huddersfield, and I did not get tripped.

    There's clearly a bug there, but it seems to be intermittent (on PC at least).
     
  3. Trim

    Trim Active Member

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    An update:

    I've re-run the scenario, taking my time out of Leeds, and I've discovered the reason I didn't see a signal is because there isn't a signal at that location at all. I replayed it again and this time took a series of screenshots. I think this pair show the situation well enough. The blur in the bottom of the windscreen in the second picture is the 15 board for the diverging line which is fairly easy to make out in the top picture if you view it full size :
    upload_2020-3-29_16-22-54.jpeg

    upload_2020-3-29_16-23-19.jpeg

    If you want to complete the scenario, you could try quickly accelerating to 10 and then holding the speed at 10 till the limit goes up to 20. I'll run it again doing exactly that, and see what happens.

    Yup, I got through it fine. Look at the time, though. A minute earlier than the previous run. No speeding either.
    upload_2020-3-29_16-37-24.jpeg
     
    Last edited: Mar 29, 2020
  4. Sintbert

    Sintbert Well-Known Member

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    The bug is in the core, it just randomly hits you with that "signal passed at danger". Happend to me on other routes.
     
  5. Trim

    Trim Active Member

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    No. There is nothing random at all. It is repeatable and predictable; you (or rather, the devs) just need to find the cause.

    I have just run the same train in timetabled mode, selecting a fine spring day and a class 45 (just in case there is something special about the class 47 and the rainy day in the scenario), and I got tripped the same as before (driving again at a relatively leisurely pace), but this time as I was driving along, I thought I would check the map to see what else was going on. Lo and behold, there is something else very particular to this train, something where driving slowly is likely to make a difference.

    This particular train is followed by that bloody Saturday Special, and the reason I curse it is because it is not given any passenger loading time at Leeds, and even if you spawn in on foot to drive it, it has so little time in the platform that it is impossible to prep the back cab and walk to the front of the train and prep that to be able to depart on time. My gripe with the Saturday Special is a little beside the point, but what is to the point is that the train this thread is about (the 08:21 Leeds to Manchester) is scheduled to actually depart Leeds at 08:22:30, and the Saturday Special is scheduled to depart Leeds at 08:25:00. AI drivers don't mess about, so if the player-driver of the 08:21 does not get a move on, then the Saturday Special will be stopping at reds behind it, and this is exactly what happens.

    Now, the point where we get the Service Failure: Signal Passed at Danger message is suspiciously close to where the back of the train clears the preceding signal L72, which set me looking at how the various signals behave and what the Saturday Special does, using both the map and camera 8, re-running the scenario sevral times. There are some distinct oddities, but I have found the immediate cause of the service failure, although I don't know what part of the game code is at fault. What I do know, however, is that if the devs programmed the signalling to behave as real signalling behaves, the service failure would never have happened. I've said before and I'll say again:
    Give us protypically-correct signalling

    There are two trains and two signals, so it is not difficult to explain. The first signal is L102 on a gantry at Leeds City West Junction. We pass it at green, and it remains green till the back of the train has passed, when it turns to red. This is is fine. A little while later, the Saturday Special pulls up to this signal and stops.
    The next signal is L72 which we also pass at green. As soon as the engine passes the signal, it turns to red, but the subsidiary signal (which had been unlit) shows two whites, and on the map it is shown as a yellow. This is bizarre, but I don't think it is related to the problem in this thread. Immediately the back of the train passes this signal (and it really is immediate), the subsidiary lights are extinguished and the signal on the map changes to red. At the same moment, signal L102 changes to yellow. THIS IS WRONG!

    Here are two screenshots. Signal L72 and the back of the 08:21 Leeds-Manchester train are on the left; signal L102 and the Saturday Special are on the right:
    upload_2020-3-29_18-1-55.jpeg

    upload_2020-3-29_18-2-8.jpeg

    I cannot emphasise how wrong this is. British railway signalling since Victorian times has been based on fixed blocks with fixed overlaps, something which has changed in recent years but was very much still the case for the NTP route in the 1980s. The standard distance for overlaps laid down in signalling regulations was 1/4 mile, but with three-aspect signalling and such low speeds as there are here, I expect the overlap for signal L72 would have been 220 yards, and it may have been less. The bottom screenshot shows no distance at all (for reference, the rear carriage of the train on the left, the BG van, is 19 yards long).

    The Saturday Special now has a proceed aspect, as you can see in the second map screenshot, and it does proceed, and this is what happens:
    upload_2020-3-29_18-32-59.jpeg

    upload_2020-3-29_18-33-22.jpeg

    It is the Saturday Special passing signal L102 that triggers the Service Failure: Signal Passed at Danger message (even though the signal was clear when the train passed it), but it is the player-driver of the 08:21 Leeds - Manchester who gets booted out of the game, since the programmers clearly never foresaw an AI driver passing a signal at danger.

    The AI driver did not pass the signal at danger, of course*. What I think happens (although this is only a guess), is that the Saturday Special enters the block section beyond signal L102, and a different part of the game's code (which presumably knows about overlaps) realises that the line is not actually clear because of the preceding train, and it is this that crashes the game.

    Right, Devs. I've now done my bit in working out what's wrong here. Please can you sort it out?
    If you want a copy of the signalling regs (or the rule book) to refresh your memories of how British railway signalling of the 1980s should work, just let me know, eh?

    A belated thought:
    *...however, L102 did change to danger the moment the front of the train passed it. That's odd, isn't it, since it tayed at green all the time my train was passing it, till the rear of the train passed the signal. I very much suspect this discrepancy is related to the issue at hand.
     
    Last edited: Mar 30, 2020
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  6. Tonto62

    Tonto62 Well-Known Member

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    Does anyone know if this is an old problem or has it emerged since the recent update for the German dlc?
     
  7. Trim

    Trim Active Member

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    I'd certainly driven this train before with no problem, because I had a silver medal for it (it is one of the first services in Journey mode in NTP). The reason I went back to it this morning was because I was looking for a run to repeat which didn't have a gold medal, and this was the first one I found. However, if you leave Leeds reasonably quickly, especially if you keep very close to the 10 mph speed limit rather than dawdle along at 8.5 - 9 mph (which is all it takes to get the service failure), then you outrun the Saturday Special without any problem.

    The 09:21 and the 12:21 for players with Heavy Freight might also be a problem, since there are oil trains following behind at 09:23 and 12:21 (??? scratches head) respectively. I've played the 09:21 but not the 12:21, but of course I could have played the 09:21 when I didn't have BR Heavy Freight installed. The oil trains won't accelerate as fast as the DMU, but with the long 10 mph speed limit, this might not make much difference.
     
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  8. Tonto62

    Tonto62 Well-Known Member

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    I did the 1221 once and arrived on time at Huddersfield only for the oil train to be signalled past whilst I was waiting departure time! To be fair, I've done it since and all was well.
     
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  9. Trim

    Trim Active Member

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    Ooh! I'd never noticed dodgy pathing decisions in the up direction at Huddersfield (it never crossed my mind to look). As you know, I reckon the decision point for down trains is considerably further from the station than it ought to be. It's actually, somewhere between Marsden and Slaithwaite but since the signalling here is two-aspect plus repeaters, there is no need for a decision to be made until a train is approaching the repeater for the signal before the tunnel, as this is the first yellow a driver would see. Not that there would be anything wrong with earier decision-making, if only the Huddersfield signalman had the imagination to realise that a down freight approaching Slaithwite will take a good six minutes to get from there to Huddersfield, so if there's a train already at Huddersfield that is scheduled to depart within those six minutes then the freight ought to be held for it. Alternatively if the signalman wasn't so insistent on not clearing starters till trains had stopped (or departure time for trains starting at Huddersfield) then this bloody stupid situation would probably not arise.
     
    Last edited: Mar 29, 2020
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  10. Sintbert

    Sintbert Well-Known Member

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    I had the error on the new German DLC, passed a green signal and got the message. I restarted the same service again, just to check. and the error did not repeat itself.
    What you describe with the train in front may also be a bug, but its not the one i had, because already the presignal was clear as i approached it.

    Also as seen from old devstreams, the game works with small sections of track that are counted as occupied. So i don't think there is any system that checks for more overlap than to the signal itself. On the older routes like Somerset you can see that system in action when you get a green signal just as soon as the opposing train clears the heartpiece of the switch in front of you, while still being well within your profile.
     
  11. Kim1087

    Kim1087 Member

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    i'm getting the same thing on GWE and it's not just services; I'm getting kicked out on scenarios as well for false SPAD's
     
  12. Trim

    Trim Active Member

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    While I can only speak for the particuar SPAD in this thread, which is - so far as I can see - repeatable with a precise set of circumstances that cause it, I suspect that many or all of these other SPADs might also be traced to a particular cause. If you say what the service or scenario is, and where/when it happened, it might be possible to trace it.
     
  13. -PjM-

    -PjM- Well-Known Member

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    Although I've not yet encountered one myself it's interesting that these SPADs seem to be occurring recently. Or at least being reported. There was this one over here...
    https://forums.dovetailgames.com/threads/gwr-journeys-1p51-hereford-to-london-paddington.21258/
    ...which may also be caused by an AI train. Perhaps there's been an update that's affected something.
     
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  14. Tonto62

    Tonto62 Well-Known Member

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    I suspect this is the case and fortunately I haven't downloaded the latest update. I'm staying offline until someone lets us know what's going on.
     
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  15. wytse106

    wytse106 New Member

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    I had simular false spad message at the same location in the 12.21u leeds to Manchester.

     
  16. rikoshea

    rikoshea New Member

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    I had something similar but I was in the BR class 47 but for some reason it lacks power.All brakes off and all I could muster was 24mph up hill think the incline was steep.But it failed me just as I was about to come into a station all green lights.So I did it again and passed it only problem was the speed of the train still shocking slow but I was late getting to destination by 20mins but still passed.
     

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