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| Crannaford AHB fails when long train stopped at Cranbrook 13/04/2020 at 22:35 #125756 | |
Albert
1313 posts |
Save attached - 6 car train (138m) stopped in Cranbrook station, seemlingly overhangs the TC controlling the level crossing, even though the station (looking at online maps) seems to be a mile away from the crossing. Doesn't happen always - in my game there seemed to be a 50/50 chance whether the crossing fails or not. But this could have been because delayed trains call at the station for a shorter time. EDIT: just to clarify, I am talking about down trains (towards Exeter). Post has attachments. Log in to view them. AJP in games Last edited: 13/04/2020 at 22:52 by Albert Reason: None given Log in to reply |
| Crannaford AHB fails when long train stopped at Cranbrook 13/04/2020 at 23:12 #125758 | |
Simdmuk
153 posts |
I found the same thing when testing, its random. For info, Cranbrook LC is 165.20 (miles/chains) and Cranbrook station 166.15. Last edited: 13/04/2020 at 23:13 by Simdmuk Reason: None given Log in to reply |
| Crannaford AHB fails when long train stopped at Cranbrook 14/04/2020 at 00:48 #125760 | |
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bill_gensheet
1314 posts 
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Are either of you on Mantis ? May be related to these two bugs : 24433 and 23626 If so compare to or try similar tests, especially the one with the user phone call. It is almost behaving as if the 240 second LC occupation timer (which alerts the failure) has become one track circuit displaced from the actual LC. Watching a test train, I saw the crossing raised as the train entered the last 'invisible' track circuit of length 1482m. As the station stop is only 74m into the following visible track circuit, a long train is still on the 1482m one as well. However this should be clear of the crossing. Bill Log in to reply |
| Crannaford AHB fails when long train stopped at Cranbrook 14/04/2020 at 07:23 #125761 | |
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njimiller
138 posts |
And in addition, a very minor point but the level crossing failure message spells it as ‘Cranaford’. Thanks. Log in to reply The following user said thank you: Albert |
| Crannaford AHB fails when long train stopped at Cranbrook 14/04/2020 at 09:42 #125766 | |
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clive
2737 posts |
It does look related to those two issues, yes. This looks as if it is to do with "roll-back protection" on the AHB. If a train sits on the strike-out track circuit for too long, the crossing logic (in real life) assumes the train may be rolling back and so lowers the crossing to warn road users. The flashing red lights trigger the "Oi" call. It is normal to suppress roll-back protection if there's a operational reason for trains to stop on the strike-out track circuit (e.g. station immediately after the crossing) or rolling back is implausible (e.g. significant downwards gradient or catch points). It's possible to do this in the sim data but the sim author has to do it. In this case, if I'm understanding correctly, the strike-out track circuit is a long one. Unless there is a roll-back risk over that entire distance, I would have expected the IBJ to be in a different place or even for the long TC to be split into two for AHB control purposes (the split would not necessarily be shown on panel diagrams). Log in to reply The following users said thank you: TUT, bill_gensheet |
| Crannaford AHB fails when long train stopped at Cranbrook 14/04/2020 at 12:52 #125779 | |
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bill_gensheet
1314 posts
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Thanks Clive, To confirm at Crannaford the TC beyond the crossing is 1482m, with the station straddling the far end. At Kirknewton (Edinburgh #24433) the TC is beyond the crossing 1365m, with the station immediately into the TC. Due to timetabling stopping trains often arrive early. Due to timetabling, the same occurrence at Kingsknowe is possible but rare For these it would seem suppression might be suitable. At Auchengray (Motherwell #23626) the TC is 2945 but uphill and gets faulted by slow trains. As this is uphill, I assume a different approach is needed, eg split TC or a wrong direction strike in. Bill Log in to reply |
| Crannaford AHB fails when long train stopped at Cranbrook 14/04/2020 at 17:11 #125797 | |
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clive
2737 posts |
bill_gensheet in post 125779 said:Split TC would work, but wrong-direction strike in doesn't help - the rollback logic is invoked as the train passes over the crossing and isn't affected by the strike-in logic for the other direction (which in turn is disabled until the train has cleared the strike-out track circuit(s)). Log in to reply |
| Crannaford AHB fails when long train stopped at Cranbrook 14/04/2020 at 21:03 #125807 | |
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Albert
1313 posts |
Looking at OS maps there appears to be a slight downhill gradient here (~1 in 150-200). Probably not 'significant' enough to warrant removing roll-back protection. clive in post 125766 said: In this case, if I'm understanding correctly, the strike-out track circuit is a long one. Unless there is a roll-back risk over that entire distance, I would have expected the IBJ to be in a different place or even for the long TC to be split into two for AHB control purposes (the split would not necessarily be shown on panel diagrams). I don't know what you mean by IBJ, but given Cranbrook station was a recent addition to the sim, there may well have been some change on the ground that wasn't implemented in the sim, such as moving the track circuit break away from the platform. Looking at a map of Cranbrook station, it appears the only entrance to the platform is at the near end, so I'd expect trains to stop at the near end by default. As this bug appeared only after the introduction of 6-car trains, they apparently do not - and I can imagine developers never thought that stopping position would be important at a simple halt like this! AJP in games Log in to reply |
| Crannaford AHB fails when long train stopped at Cranbrook 14/04/2020 at 21:21 #125808 | |
DriverCurran
682 posts |
IBJ = Insulated Block Joint
You have to get a red before you can get any other colour Log in to reply |