Model railway signal box interior advice

Steamer in post 159467 said:

On double (or more) track lines worked under Absolute Block, the UK code is 3-5-5 and works much the same as you describe, the train would be cautioned at the previous signalbox (either verbally or via a green flag held out of the window) before entering the section. The 'Warning' could be upgraded to a full line clear by 3-3-5 if the full clearing point subsequently became available prior to the train entering the section.

How is 3-3-5 useful, given that the approaching train has already entered the section and there is no way to communicate that information from the signalbox in rear to the approaching train?

Steamer in post 159467 said:

Semaphore stop signals must be held at danger until the train is almost at a stand at them unless all signals to which the preceding distant signal applies can be cleared. While technically a driver passing a distant at caution could infer from an already-clear home signal that the signaller had since been able to clear everything, drivers would generally proceed in the expectation of each stop signal being at red. There were various unofficial 'hurry up' signals given by signalmen in the past to reassure the driver that they had the road and could open up a bit.

How is that procedure modified with fixed distant signals?

Steamer in post 159467 said:

That wouldn't be used on single lines, as the clearing point would extend into the loop, there's just a specific ban on both trains entering the loop itself simultaneously, as any minor overrun could result in a collision. Not necessarily a requirement if there's a sufficient distance between the signal and the points, but as passing loop layouts are typically quite compact it would be rare to have that much space.

I suppose the alternative would be if a crossing loop had overrun stub sidings, or at least catch points, beyond the departure home signals?

[quote=Steamer;post=159467]On double (or more) track lines worked under Absolute Block, the UK code is 3-5-5 and works much the same as you describe, the train would be cautioned at the previous signalbox (either verbally or via a green flag held out of the window) before entering the section. The 'Warning' could be upgraded to a full line clear by 3-3-5 if the full clearing point subsequently became available prior to the train entering the section.

bill_gensheet in post 159398 said:

Anothersignalman in post 159396 said:

Ron_J in post 159389 said:

As this is a crossing point on a single line, what do people who wish to get on or off at the station do if their train is the second to arrive when crossing another train?

Shunt and redock procedure. Train A arrives platform, then reverses back, then pulls forward to mainline. Train B runs to platform and continues, then Train A proceeds.

Where single platform passing loops existed in the UK, it would be arranged never to cross two stopping passenger trains.
Loop for goods or through only.
(Abercairney, Mound, Saffron Walden)

<snip>

I second that.

Highley (Severn Valley Railway) is an example that remains to the present day. In fact, unless the loop was signalled to passenger standards, it would be illegal to accept two trains simultaneously from the box in rear, as the clearing points would overlap each other. (Certainly Highley may not, unless I missed something when I read the SBSIs, accept from both directions simultaneously.) So to cross trains you'd need to wait until the first one you'd accepted had arrived and (either) been put 'in clear' in the loop, or had tipped out and been shunted into the loop, before you could even accept from the other direction.

If the loop was signalled to passenger standards, the relevant clearing point would be the fouling point at the opposite end of the loop - but both approaching trains would need to be brought quite or nearly to a stand, then each admitted in turn (not allowable to run them both in simultaneously).

Steamer in post 159467 said:

Semaphore stop signals must be held at danger until the train is almost at a stand at them unless all signals to which the preceding distant signal applies can be cleared. While technically a driver passing a distant at caution could infer from an already-clear home signal that the signaller had since been able to clear everything, drivers would generally proceed in the expectation of each stop signal being at red. There were various unofficial 'hurry up' signals given by signalmen in the past to reassure the driver that they had the road and could open up a bit.

How is that procedure modified with fixed distant signals?

Steamer in post 159467 said:

That wouldn't be used on single lines, as the clearing point would extend into the loop, there's just a specific ban on both trains entering the loop itself simultaneously, as any minor overrun could result in a collision. Not necessarily a requirement if there's a sufficient distance between the signal and the points, but as passing loop layouts are typically quite compact it would be rare to have that much space.

I suppose the alternative would be if a crossing loop had overrun stub sidings, or at least catch points, beyond the departure home signals?

Bewdley still has something like this, albeit there have been changes during the preservation years. I have a feeling they've simplified the rules since I used to volunteer there, but I recall some fairly interesting (read complicated) working. Once working distants were installed, the old Western Regulation 4A (line clear to clearing point only, 2-2-2 acceptance) was required to be used in fog or falling snow, so an approaching train would get a distant at caution a long way back and wouldn't be dependent on seeing the innermost distants to pull up at the far end homes. Meanwhile, Regulation 5 (section clear but station or junction blocked, 3-5-5 acceptance) was authorised on the up platform for trains booked to call only (so the 3-3-3 bell signal was also in use for trains booked non-stop). There was no need for Reg 5 on the down platform because the former Tenbury line provided a clearing point; meanwhile if you needed to use the 'back platform' in the down direction the North Box had to have a full 1/4 mile clearing point and there was no Reg 5 acceptance. (Answering the query about 3-3-5, it was very common to find trains approaching from both directions simultaneously, in which case Bewdley South would accept the up road at Reg 5. As soon as the down road was clear of 13 crossover, the road could be put back and 3-3-5 sent, often while the up road was still approaching the outer home. But it didn't always happen that way of course - and in some timetables the up road was actually booked to arrive first - so Reg 5 avoided it being held outside.

If the Down Platform line or Down Middle line between this signal box and Shrub Hill Junction signal box is already occupied on the Shrub Hill Station side of the passenger footbridge, but is clear on the Shrub Hill Junction signal box side of the footbridge, the Working in Wrong Direction signal must not be acknowledged by repetition, but the special bell signal Line clear to the ground disc signal at fouling point with connection Down Middle line to Down Platform line in centre of Station (1-2-3) must be sent to Shrub Hill Junction if the line is clear to that ground signal.

When vehicles are detached and left on the Up Platform line to the rear of the Shrub Hill station signal box Up Platform line Home signal, and it is necessary for a locomotive to enter the section at this signal box and propel the vehicles in the wrong direction to Shrub Hill Junction signal box, the special bell signal May locomotive propel to your signal box, vehicles now in section (1-2-4) must be sent to Shrub Hill Junction. When the locomotive and vehicles are clear of the section, the Shrub Hill Junction Signalman will send the special bell signal Vehicles propelled clear of section (3-2-1). The Signalman at this signal box, when satisfied that the section is clear, may, after acknowledging the special bell signal (3-2-1), send the Train out of Section signal to Shrub Hill Junction.