Railway signalling discussion

The end of local monitoring ?

Discussion concerning level crossings

The end of local monitoring ?

Unread postby Mike Hodgson » Mon Jun 16, 2014 1:22 pm

The RAIB report into a near miss at Butterswood ABCL near Ulceby has just been issued and contains some interesting ideas. ... rswood.pdf

Among its recommendations are :
[*] provision of a positive indication to drivers that the crossing has failed - ie it should tell the driver when it knows it has failed (rather than relying on him not to leave braking too late should the red light continue to flash), and
[*] evaluation of the practicality of remote monitoring of power supplies and key sub-systems.

If the former is implemented, it would no doubt reduce the risk of an accident or near miss of the type which occurred at Butterswood, but what indication would be likely (different from flashing red/flashing white) to tell the driver he must expect to have to stop? Steady red perhaps?

And if the latter can be carried to full implementation, would crossing faults effectively be handled the same way as AHB faults? Would we still need the Drivers Crossing Indicator ?

The report also contains recommendations to improve equipment reliability and driver training.

Whatever solution they choose, it's likely to mean a programme to modify/upgrade a lot of crossings.
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Re: The end of local monitoring ?

Unread postby AndyB » Tue Jun 17, 2014 12:43 am

The problem with the former is that the flashing red is already a direct indication that the driver is expected to stop short of the crossing and not proceed until the crossing is operating properly, just as a steady white light was in older installations.

The key thing about AOCLs and ABCLs is that train drivers are entirely and directly responsible for ensuring that the crossing is operating properly before passing. To that extent, any driver should expect to find a crossing still open to road traffic until the moment that the DCI switches to flashing white, and brake accordingly (given that the SSRB is no less than braking distance at the indicated speed for a loco-hauled passenger train from the crossing!)

A permanent AWS magnet for the SSRB makes good sense to me.

NIR's distant monitored crossings were and are a little different. They retained the white flashing light for the driver, but it was co-sited with the SSRB, due to poor sightlines, and the drivers were expected to stop short of the crossing before continuing if the crossing was operating properly. I'm not sure whether the AOCDs had indicators in the supervising signalbox (AOCLs of course did not), but the three Cullybackey AHBDs do, including a plunger for stopping/non-stop in the Down direction. No word as yet on their replacement, although intermediate signals in the Up direction have been blacked out on the Coleraine panel ever since it was installed.
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