Wrong line movements out of bay platform (WR 1980s)

[DK123GWR]

Here is a (simplified) diagram of the situation. I have a bay platform at the bottom. Trains leaving this must cross the down line to reach the up line. Both of these lines have a speed restriction of 50mph. How would this be signalled in the 1980s on the GWML? What would the speed restriction most likely be for trains leaving the bay platform? Any help would be very much appreciated.

Thanks in advance!

[Joseph_Pestell]

Ignoring the fact that model railway pointwork has much tighter radius curves than the real thing, it is unusual for pointwork in a station throat to be suitable for 50mph. The restriction both into and out of the bay would likely be as little as 10mph and perhaps 20mph over the crossover.

 

Unless your mainline to the right has dual directional running, the signal to exit the bay is just a two-aspect simple signal. Coming into the bay, movement is controlled by a signal (2,3 or 4 aspect) with a "feather" of white lights at a 45 degree angle, placed before you get to the crossover.

[iands]

AIUI to a large extent the speed of movements out of the bay platform would depend on the type of switches used in the points. The tighter the radius, the lower the speed as a general rule of thumb. There may also be other factors that would determine the speed limit - although your diagram is depicting a straight line, any curves/cants would have a limiting factor on speeds. 

[DK123GWR]

I already had a lower speed limit over the points. What I really want to know (although I didn't make that clear) is the speed restriction for trains travelling down the up line to reach the crossover. Would this be the speed limit at the crossover?

18 minutes ago, Joseph_Pestell said:

Unless your mainline to the right has dual directional running, the signal to exit the bay is just a two-aspect simple signal.

Would this signal be interlocked with all three of the sets of points in the diagram?

Edited May 16, 2020 by DK123GWR

[Joseph_Pestell]

In that distance, I don't think that any train could accelerate quickly enough for it to be an issue. So yes, the line speed is going to be the same as that for the crossover.

 

All signals are interlocked with the pointwork that they protect and other signals.

 

You only have "two sets of points" to interlock with the bay signal: the point that gives access to the bay and the crossover. A crossover should always be treated as a single item with both points operating together. In this case, yes, the green aspect can only be shown if all the turnouts are in the reverse (i.e. curved) position.

[DK123GWR]

Thank you.

[Joseph_Pestell]

We also need to remember that a speed limit applies to the whole length of the train. So the train departing from the bay can not accelerate beyond 10mph until all of the train is on the mainline - by which time it is already onto the crossover.

[Flying Pig]

2 hours ago, Joseph_Pestell said:

Unless your mainline to the right has dual directional running, the signal to exit the bay is just a two-aspect simple signal.

 

Wouldn't a three-aspect be more likely?

[The Stationmaster]

51 minutes ago, Flying Pig said:

 

Wouldn't a three-aspect be more likely?

Definitely so.  I can't think of any WR bay line, even in such a simple situation as this, where the colour light signal reading out onto a double track running line is a 2 aspect signal, they are invariably 3 aspect.  

I do know of a situation where a signal from a bay reading onto single track branch line was 2 aspect but that was a very different sort of situation and in the most recent resignalling it was altered to 3 aspect!

[DCB]

This is a very unusual situation, a bay with a facing connection off a main line.  A "Facing Bay?"

Looking at the Western Region Quail map for 1992 I could only find 3 locations with them on the whole region,  The old Exe Valley branch bay at Exeter St Davids, a pair at Worcester Shrub Hill, and the former Down through roads converted to bays at Plymouth North Road.   

[caradoc]

There are surely more examples than that ? Off the top of my head, the Up Bay (now Platform 2) at Oxford and the east end bay, Platform 6, at the old Reading General. And other bays where direct access is available via a facing crossover on the main line, eg the west end bays 1,2 and 3, and the separately-accessed 7, also at the old Reading.

 

[The Stationmaster]

1 hour ago, caradoc said:

There are surely more examples than that ? Off the top of my head, the Up Bay (now Platform 2) at Oxford and the east end bay, Platform 6, at the old Reading General. And other bays where direct access is available via a facing crossover on the main line, eg the west end bays 1,2 and 3, and the separately-accessed 7, also at the old Reading.

 

And that's just for starters (sorry).  if you can't bays accessed via a crossover to enter via a running line trailing crossover there are loads of them  - Hayes )trails into nearest running line but has a facing crossover to reach it), Slough East (as Hayes) Slough West (facing bay off the Windsor branch). Twyford (facing bay off the Up Henley branch 1911 - 1971 (i.e. prior to full singling),  Reading (noted above),  Swindon West End in pre MAS days (facing off the Up Main into a very short bay), Bridgend (off the Down VoG), Carmarthen (off the single line),  Whitland west end (off the Up Main line),  Clarbeston Road west end (off the Up Main Line),  Newbury West (off the Lambourn branch),  Savernake West (off the Marlborough branch). Frome (off the branch via facing crossover),  Taunton east end (three, directly off the Down Main Line), Taunton west end (two directly off the Up Main Line),  Exeter east end (directly off the Down Main Line), Paignton south end (traling running line but accessed via a facing crossover), Churston (off the branch)Lostwithiel (off the branch), and more.

 

Things of course chanbged over the years mainly due to line closures and loss of local trains services but facing entry off running line was not exactly unusual in the semaphore age and of course it occurred at even more plav ces in the MAS era although in many cases it was via running line facing crossovers in that period.

Edited May 18, 2020 by The Stationmaster

[RailWest]

...not forgetting Tiverton, off the Down loop, likewise Dulverton  (though you might not count those as 'main lines' and Dulverton was not actually a dead-end 'bay' )..