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| Failed track circuit colour 04/06/2013 at 21:05 #45457 | |
Ron_J
331 posts |
Yes, there is.
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| Failed track circuit colour 04/06/2013 at 22:06 #45458 | |
GeoffM
6377 posts 
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Agreed, IECC/MCS/Westcad can all detect tracks clear when it expects them to be occupied. But it's not infallible. If the track is adjacent to a non-track circuited section (including yards/sidings etc) then there's no way to tell if the train has left the track section or there's some kind of failure. If a divide can happen in a platform track, if the platform track becomes clear, is that because the train(s) is/are now clear of the section - or is a bit left behind under some failure condition? The opposite is also true - if two tracks merge into a single track, which train actually proceeded - the one signalled to go or the other one? All the interlocking knows is that the common track section is no longer clear and that it's occupied by... something. SimSig Boss Log in to reply The following user said thank you: sorabain |
| Failed track circuit colour 04/06/2013 at 22:21 #45459 | |
headshot119
4869 posts |
" said:Agreed, IECC/MCS/Westcad can all detect tracks clear when it expects them to be occupied. But it's not infallible. If the track is adjacent to a non-track circuited section (including yards/sidings etc) then there's no way to tell if the train has left the track section or there's some kind of failure. If a divide can happen in a platform track, if the platform track becomes clear, is that because the train(s) is/are now clear of the section - or is a bit left behind under some failure condition?Is that part of the OSTO alarm? "Passengers for New Lane, should be seated in the rear coach of the train " - Opinions are my own and not those of my employer Log in to reply |
| Failed track circuit colour 04/06/2013 at 22:25 #45460 | |
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GeoffM
6377 posts
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" said:" said:OSTO=Out of Sequence Track Occupation, but yes it does include clearance. I can't remember whether that's a specific term for Westcad or MCS though - the former I think. IECC track monitoring was originally done by the ARS software, of all things, in fact I think it still is, though it's been expanded to automatically turn off certain subareas if a SPAD is detected. The way IECC and MCS does it is completely different; not sure about Westcad.Agreed, IECC/MCS/Westcad can all detect tracks clear when it expects them to be occupied. But it's not infallible. If the track is adjacent to a non-track circuited section (including yards/sidings etc) then there's no way to tell if the train has left the track section or there's some kind of failure. If a divide can happen in a platform track, if the platform track becomes clear, is that because the train(s) is/are now clear of the section - or is a bit left behind under some failure condition?Is that part of the OSTO alarm? SimSig Boss Log in to reply |
| Failed track circuit colour 05/06/2013 at 11:33 #45472 | |
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Stephen Fulcher
2084 posts
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I have seen a few wrong side track circuit failures in my career, but never one caused by the relay failing to operate. The three causes I have seen have been rail head contamination, high resistance back contact of a relay (preventing the red lights on the signalmans diagram from lighting, but other than that the interlocking function was protected as only one contact was defective), and defective lineside cabling. Network Rail now has Remote Condition Monitoring on some track circuits which is designed to detect when a track circuit might be about to fail by monitoring the current drawn by the relay. This system has proven effective at identifying rusty rails. The OSTO on all systems is, like Geoff said, not totally infallible. A common fault we used to have when I was a Team Leader at Leamington was TI21 track circuits failing due to a dodgy tuning unit, which basically meant that when a train hit one track circuit the frequency bled through to the next track circuit and occupied that as well. This mode of failure never generated the alarm as the track circuits had occupied in sequence, just not by a train. Also of note here, no SPAD alarm was generated either if the train passed the signal at danger, which frequently happened. The first the Signalman knew about it was when the train stopped to report either a Change of Aspect or an Irregular Aspect Sequence. As for Wrong Side Failures being included in SimSig, I am not sure what value such an addition would really have. The "hardcore" railway enthusiast or professional might know what to do about it, but the average user would simply be confused to hell and back, and the simulations would be bordering on unplayable for them. Log in to reply |
| Failed track circuit colour 05/06/2013 at 15:42 #45476 | |
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Firefly
521 posts |
Quote:As for Wrong Side Failures being included in SimSig, I am not sure what value such an addition would really have. The "hardcore" railway enthusiast or professional might know what to do about it, but the average user would simply be confused to hell and back, and the simulations would be bordering on unplayable for them.Agreed The net result would be that the piece of equipment would be signed out of use for many many hours whilst the system is tested. Therefore just chose a track circuit, consider it disconnected by the S & T and put a reminder appliance on the protecting signals. You could also grant imaginary line blockages to allow staff access to site. FF Log in to reply |
| Failed track circuit colour 05/06/2013 at 15:46 #45477 | |
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Stephen Fulcher
2084 posts
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I did that to frustrate Sam Tugwell during a multiplayer session once. He had Exeter Panel 3 and was bored so the S&T went there to start FPL testing points!
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| Failed track circuit colour 05/06/2013 at 20:11 #45488 | |
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headshot119
4869 posts |
I've once had a track circuit fail wrong side, it did rather confused me at first, I thought I'd mistook the first track circuit in the sequence being occupied. Though in this case the piece of track hadn't seen a train in a few months.
"Passengers for New Lane, should be seated in the rear coach of the train " - Opinions are my own and not those of my employer Log in to reply |
| Failed track circuit colour 07/06/2013 at 22:04 #45539 | |
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john_s
31 posts |
Sorry to come in a bit late on this one, but if you want a diagram showing how the humble DC Track Circuit shows 'occupied' in the case of both rails shorted and also for broken cabling/failed power supply - here is a nice diagram: http://www.lymmobservatory.net/railways/sbdiagrams/braithwell_q55.jpg Notice how the battery and TC relay are at opposite ends of the track circuit, and the relay must be energised to indicate 'clear'. The indicators seem to be a mixture TC indicators and locked/free indicators. Last edited: 07/06/2013 at 22:09 by john_s Log in to reply The following users said thank you: maxand, sorabain |
