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Paddington Station

Current and future British signalling (UK except Northern Ireland)

Paddington Station

Unread postby scarpa » Tue Apr 25, 2017 11:27 pm

Earlier work carried out at Paddington Christmas time period joined platforms 12 and 13 together ,previously platform 12 was in advance of platform 13 accessed from platform 11 via a crossover .The longer combined platform is now platform 12 . Platform 14 remains unchanged. The platform length designed to handle at least 8 coach 387 units but would be able to accomadate a H.S.T.
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Re: Paddington Station

Unread postby rower40 » Wed Apr 26, 2017 1:47 pm

In signalling terms, platform 12 (accessed via the crossover) has been abolished, platform 13 extended and renumbered 12!
Platform 11 used to have a mid-platform signal, protecting the crossover. If there was a long train in that platform, (standing on the crossover - therefore beyond the mid-platform signal) then the operation of the TRTS would cause the train's description to step forward to the front signal. This could confuse ARS, as it would 'think' that the train had now left (possibly very early) and would then continue to set route for it.
It didn't occur often (if at all) at Paddington, but it's very common at platforms 9 and 10 at Liverpool Street which have a similar layout - mid platform signals protecting a scissors crossover.
We've identified a solution (now implemented at platform 16 Edinburgh) but it requires an additional latch and a bit of logic in the SSI, so no chance of it being introduced at Liverpool Street. The abolition of the crossover at Paddington means that the mid-platform signal on platform 11 has now gone too.
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Re: Paddington Station

Unread postby scarpa » Wed Apr 26, 2017 10:49 pm

Thankyou rower 40 on the information concerning TRTS and ARS. The former offset bracket signals which had 2 aspect signals fitted before being abolished along platform 11 and 12 now have full size banner signals fitted to the signals so a good use made of the former signals.
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Re: Paddington Station

Unread postby Mike Hodgson » Thu Apr 27, 2017 6:24 pm

So it's a (slight) reduction in operational flexibility caused by software constraints. The hardware is being modified to suit the software.
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Re: Paddington Station

Unread postby John Hinson » Fri Apr 28, 2017 6:38 am

Mike Hodgson wrote:So it's a (slight) reduction in operational flexibility caused by software constraints. The hardware is being modified to suit the software.

The changes might actually be for operational convenience of the supa-dupa new trains . . .

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Re: Paddington Station

Unread postby StevieG » Sun May 7, 2017 10:32 am

rower40 wrote: " .... Platform 11 used to have a mid-platform signal, protecting the crossover. If there was a long train in that platform, (standing on the crossover - therefore beyond the mid-platform signal) then the operation of the TRTS would cause the train's description to step forward to the front signal. This could confuse ARS, as it would 'think' that the train had now left (possibly very early) and would then continue to set route for it.
It didn't occur often (if at all) at Paddington, but it's very common at platforms 9 and 10 at Liverpool Street which have a similar layout - mid platform signals protecting a scissors crossover.
.... "
Is it totally correct to call the relevant signals at Liverpool Street, 'mid-platform signals'?
The term conjures an image of signals protecting point connections halfway(-ish) along a platform, or possibly just a different portion of a platform normally capable of legitimate occupation by a separate train, when a signal was at some time deemed necessary.

The scissors connections in Liv.St. platforms 9 & 10 are an adjunct to the adjoining complex layout of the station's main 'throat', far from being near the middle of the platforms, and permit trains a couple of coach / loco lengths shorter than the maximum accommodatable to, on the one hand leave No.10 and reach the Down Suburban line, and on the other increasing the alternative routing (facilitating other moves in parallel) available for movements between 9 and the Down and Up Mains. And the 'mid-platform' and platform Starting(?) signals 'proper' are separated only by the length of the scissors (in fact one Starter is a few feet in rear of the toes of the adjacent crossover's north end point).

As a shift manager there during Liv. St. IECC's first six years, while conscious that I am writing some twenty years after leaving 'front line' IECC operation of what is now known as IECC Classic, I don't recall the operations out of 9 & 10 being a problem ; I don't remember whether, for shorter trains standing within 25 or 29 'mid' signal, TRTS operation stepped the TD forward to 27 or 31 (I am thinking perhaps, not), though for longer trains standing beyond 25 or 29 I feel more certain that it did.
TRTS shouldn't of course be operated significantly before scheduled dep. time, unless for such as ECS trains, but I believe whatever, that no forward routing by ARS from the 'proper' Starters happened more than the customary 1 - 2 minutes before time unless initiated by the signaller wanting the train to leave early.
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