Deafdoggie
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- 29 Sep 2016
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Hi. Can anyone in the know let me know how far in advance (in time) the barriers are lowered at Wem before a train?
Barrier down times of between two and five minutes seems to be most typical at Wem, but could well be shorter or longer. You'd probably have to do a careful analysis of all train workings through Wem using something like RealTrainTimes (not just those handful of passenger trains that actually stop at the station) to work out when the most likely "barrier up" gaps in the daily train working schedule are.We're trying to organise a road timetable, but want the service to avoid being caught by barriers
Thank you. Most helpfulAh, found it. Wem is an "MCB-OD". This means 'manually' (but actually usually automatic now the OD has been added) controlled barriers with obstacle detection. Lowering is triggered automatically by trains when they are a fixed distance away, usually the point a train travelling at the highest speed would be to get the barriers down and allow the closure sequence to complete whilst still displaying a green to the train.
The sequence is described on pages 19 and 20 of this: https://www.orr.gov.uk/media/10713/download
You can see it on OTT maps here: https://www.opentraintimes.com/maps/signalling/cre-shr#T_WEMM
The crossing will need to be down and cleared for the signal to clear, so for trains heading towards Nantwich this will be several minutes in advance as the signal is way back, and before the station. If the train is a stopper then the crossing will be down while the train approaches, does it's station stop and goes off again, so you're easily looking at 4 to 5 minutes at least in those cases. Linespeed is 90mph so the train has to be a good way off to keep it on greens.
You'd have to look at the mix of trains and train types - a freight will not be doing 90 so will of course take longer to go through - again, probably 4 mins or so.
Not sure if that's helpful but it's a start!
All I can say is, having caught a train there once and had chance to watch them in inaction, a long time. Especially if you have trains coming in opposite directions - a bit like Wedgwood and Barlaston.Thank you. Most helpful
Sadly this is not the case at Wem or at any of the other OD crossings on the Crewe - Shrewsbury line. The timing of the barriers is dependant on how fast the system thinks your train should be, and/or where it thinks you should be stopping at.Ah, found it. Wem is an "MCB-OD". This means 'manually' (but actually usually automatic now the OD has been added) controlled barriers with obstacle detection. Lowering is triggered automatically by trains when they are a fixed distance away, usually the point a train travelling at the highest speed would be to get the barriers down and allow the closure sequence to complete whilst still displaying a green to the train.
A real bugbear of mine is that overnight, for some reason the barriers aren't lowered anywhere near in time to allow freights to pass at 60mph. It's not uncommon to be checked right down at all of Wem, Prees, Wrenbury and Newcastle Road, I've tried approaching the repeaters at 50mph and 45mph and there's no difference, they still show that yellow until you're past them.Sadly this is not the case at Wem or at any of the other OD crossings on the Crewe - Shrewsbury line. The timing of the barriers is dependant on how fast the system thinks your train should be, and/or where it thinks you should be stopping at.