Page 1 of 1
| Bidirectional signalling in UK - main routes Today at 11:35 #158822 | |
Ignacio
14 posts |
Hi all, probably one of the UK experts can answer why in UK bidirectional signalling, also on main train routes, seems to be rather occasionally implemented. It came to my mind while using the busy Doncaster simulation where no bidirectional signalling for the main London to York line exists. Is it because of security reasons? Or cost implications? How is the train traffic organized when reconstruction work in a train section starts? There I assume a bidirectional signalling could ease maintaining (limited) train traffic using the second (parallel) track. In Austria and Switzerland bidir signals are usual, in Germany where I live also quite often. Simply interested in understanding the difference! Thanks a lot, Cheers Ignacio Log in to reply |
| Bidirectional signalling in UK - main routes Today at 16:13 #158833 | |
GeoffM
6364 posts |
Two common reasons: cost of installing and maintaining equipment which should rarely be used; and because capacity is so much lower that you're going to have to run buses or other alternate transportation anyway, so why run any train service at all? There are, of course, exceptions. Rugby's four track sections have two lines signalled in both directions, and simplified bi-directional signalling is installed in many places (often with 15 minute or worse headway; okay for Sunday services and an occasional "get out of a hole" situation, but not much more). SimSig Boss Log in to reply The following user said thank you: Ignacio |
| Bidirectional signalling in UK - main routes Today at 16:35 #158834 | |
|
kbarber
1732 posts |
As Geoff says, cost is a major driver. UK signalling tends to be rather more complex (overlaps are uncommon, for instance, in many other countries' systems) and UK signal engineers tend to be rather conservative. So the idea of BiDS was a long time coming. Somewhere in my father's papers is a paper written by one Chris Green, at the time an operations manager in the old Southern Region, describing the system used in Germany and proposing installation of a similar system (with some appropriate modifications) in the UK. (One of the modifications was that separate 'wrong-line' signals would be provided. Apparently in Germany when BiDS was in operation signals for the 'right line' would apply to the 'wrong line' when it was being used in the reverse direction. Which, to me, sounds like unduly complicated circuitry but maybe DB circuits allowed for signals to be switched across in that way. That particular feature suggests BiDS was for engineering work only and couldn't be used for traffic reasons, a major difference from UK BiDS.) Quite apart from cost, I have an idea there was a stage when Health & Safety considerations were cited as a reason for not using BiDS. Certainly the UK implementation, at least on the Western Region, had a 'patrolman's lockout' so engineers staff could bar use of BiDS while they conducted their regular examinations of the track. Given there was a period (late 1980s perhaps?) when the Health & Safety Executive was actively considering prohibiting Single Line Working during engineering works, that seems plausible. Beyond that, as Geoff says there are few locations now where BiDS would offer more than a marginal benefit - train services are much more intense than they were even 30 years ago. Log in to reply |
| Bidirectional signalling in UK - main routes Today at 17:04 #158836 | |
|
Ignacio
14 posts |
Many thanks, GeoffM and kbarber! Seems to be really differently handled in UK versus Germany. I am not working as professional signaller at Deutsche Bahn, but would agree that BiDS is often not possible to use because of overbooked tracks...so it is not a proper means to increase resources...
Log in to reply |