Distant at caution

How does it work. In real life, if you're a signalman and you can clear some of your stop signals, but not all, can you? Or do you have to go through the whole bring the train almost to a stand at each stop signal palaver?

If you're a driver and you pass a distant at caution but see the home signal off, do you have to remember your distant, hold back, not assume that all signals are off and instead proceed at caution (surely not 40 mph if you're driving a freight train as some stop signals are very close together?) Or can you open up and accelerate to full line speed, safe in the knowledge that if one's off, they must all be?

TUT in post 108227 said:

How does it work. In real life, if you're a signalman and you can clear some of your stop signals, but not all, can you? Or do you have to go through the whole bring the train almost to a stand at each stop signal palaver?

This definitely still happens- I was at Gilberdyke last year, and saw it happen with to a freight train from Selby that was approaching just after a stopping service left. I don't think the freight was brought to a stand at any point (or it may have been stopped at the outer home as the stopper came off the branch).

Quote:

If you're a driver and you pass a distant at caution but see the home signal off, do you have to remember your distant, hold back, not assume that all signals are off and instead proceed at caution (surely not 40 mph if you're driving a freight train as some stop signals are very close together?) Or can you open up and accelerate to full line speed, safe in the knowledge that if one's off, they must all be?

I think it's a safe bet that defensive driving policies these days would require a driver to observe the last signal as clear before accelerating away. I'm sure Mr. Barber will be along in due course to tell us how it used to be done!

Most simulations don't enforce the 'bring almost to a stand rule', but a couple do- Saltley implements it automatically (so you can set the route but the signals won't clear until the appropriate conditions are met).

In the case of semaphore signals the distant signal will normally only clear if all the stop signals under the control of the signalbox show clear.

If the distant is at caution in most cases all but the starting signal can be cleared, (local instuction may differ)

In the part you asked about having passed the distance at caution but then sight the home at clear it does not mean that you have a clear run though the section you would in essence still slow down as at the time of approching the home the section ahead is still blocked, the only time a driver can assume a clear run though is only if the distance signal shows a clear.

When a stop signal is at Danger the stop signal next in rear of it and worked from the same signal box must not be lowered for an approaching train until the train is close to such signal and has been brought quite or nearly to a stand. (more)

Taking account of the description of Rule 39 above, it can be seen that if a driver passes a distant signal at on, he will be prepared to find the stop signal ahead on, but if that signal is off (without his brought nearly to a stand) he can expect all stop signals ahead (worked by that box) to be off.

In the case of semaphore signals the distant signal will normally only clear if all the stop signals under the control of the signalbox show clear.

As always with old fashioned signalling, there's lots of complications. But essentially, you do have to bring the train almost to a stand at each signal in turn and it is all down to the signalman to do the job right.

A driver having had a distant at caution should never assume anything, even if the home is clear as he approaches; the signalman may have pulled off early (we did sometimes need to visit the 'East Wing', sometimes hurriedly - there's a limit to how long the human body can hold on, especially with the amount of tea drunk in a signalbox). Of course, if the starter's visible on approaching the home, the driver can see what's going on and can drive accordingly.

There were locations where an exception to the rule was specifically authorised. In that case there would be an entry in the Sectional Appendix. Several stations on the Ely - Norwich route used to have such exemptions - the Appendix specified that the rule (in Section C in my day IIRC) would not apply to trains booked to call at those stations and that the driver could expect the home to be cleared with the starter at danger. In each case there was a level crossing on the approach side of the station, so this both gave the passengers a smoother ride and cleared the crossing more quickly.

The Rule Book specified an exception to the rule where the home (and others) was a colour light signal with full braking distance to the following stop signal; in that case, you just pulled off. Where there wasn't braking distance, you had to apply the rule, even though you had a 3-aspect colour light home; in some cases (but by no means all) you could reverse the lever and, if the signal ahead was at danger, the signal would remain red until the berth track was occupied (with or without a timer to enforce a further delay).

Unless there is an exemption (either in the Sectional Appendix or the SBSIs), I don't believe there is any authority to clear the home early for a train being looped. For any junction, unless there is a splitting distant the requirement for a train on the diverging route is to keep the home at danger until the train approaches it unless it is booked to take the diverging route. (That would particularly apply on a 4-track railway, of course). If the signal is an approach-released colour light the lever can be reversed at any time, and of course that means all trains for the diverging route would be checked. There was also an exemption for densely trafficked suburban areas, where the signal for the diverging route could be cleared as soon as possible.

4.5 Clearing a stop signal when the next signal is at danger

If you cannot clear a stop signal, you must not clear any associated signals on the approach to it until the train has stopped or nearly stopped at each signal in turn.

You do not need to apply this instruction if the stop signal on the approach to the stop signal at danger is a colour light that can show a yellow aspect, and:

• is controlled by the occupation of a berth track circuit, or
• requires the line to be clear up to and including the overlap track circuit of the signal at danger

If you have stopped or nearly stopped at either of the following types of signal at danger and that signal changes to a proceed aspect or indication, you must be prepared to stop at the next stop signal worked by the same signalbox.
• A colour light signal that cannot display a yellow aspect.
• A semaphore signal.
This does not apply to the signal controlling the entrance to an intermediate block section.

Current rule book GERT8000-S7 Iss 3, applying to drivers:
Quote:

If you have stopped or nearly stopped at either of the following types of signal at danger and that signal changes to a proceed aspect or indication, you must be prepared to stop at the next stop signal worked by the same signalbox.
• A colour light signal that cannot display a yellow aspect.
• A semaphore signal.
This does not apply to the signal controlling the entrance to an intermediate block section.

This suggests that, for those types of signals, if it's already clear then you don't need to worry about the rest of the signals controlled by that box.

I recall a SPAD in similar circumstances, at a different location - the home signal had been cleared far too soon, meaning that the driver was misled into thinking that the section signal was cleared when it had been held at danger. I'm pretty sure that the driver was exonerated, at least as far as Network Rail were concerned, again supporting the view that they consider it reasonable for drivers to be led to believe that the first one off (without being checked down) means that they're all off, even if the TOCs disagree!

Would this be the incident at Greenford in 2014? The report makes interesting reading.

https://www.gov.uk/raib-reports/unauthorised-entry-of-a-train-onto-a-single-line-at-greenford

On the GWR, there were some locations where there was not sufficient braking distance between the outermost home signal of box A and the outermost home signal of box B so to avoid having to resort to regulation 4A, box B had control of A's distant. If B was unable to obtain line clear from C then A's distant would remain at caution even if A had pulled off all their signals. In some cases however I note that no distant arm was provided below A's home signal and so even though the train would have been cautioned at A they would then see a clear home signal before sighting the starting/inner home signal with a distant for A below at caution. I asked elsewhere about the risk of a train accelerating upon seeing the first home signal clear and accelerating towards box B before seeing the distant (on the same post as A's starting/inner home) at caution but was told that the driver was never to assume that the line was clear through if they had passed a distant a caution, regardless of if the outermost home had been cleared or not. I wonder in this case if the drivers would have known that the distant was controlled by both boxes.



Box A Distant (Controlled by B) -------- Box A Home ---------- Box A Inner Home/Box B Distant -------- Box B Home