Request to pass signal at danger?

[Inversnecky]

A query from Train Simulator, where you can request permission from the box to pass a signal at danger on leaving a station.

If it’s safe enough to pass, why does the signaller not just change it to yellow?

Or is it assumed that the block still has a train on it, so you have to proceed with great caution (have never seen another train in TS, though)? Kind of analogous to a shunt signal permitting an engine onto a track with a stopped train just ahead?

 

[Gloster]

Fairly often the signaller can’t clear the signal for a technical reason, such as a track-circuit failure. Even if the signaller can clear it, making the driver do something unusual and contrary to all the normal rules, hammers it in that he should be cautious and fully follow the instructions that the signaller has given him or her. That was what it was in my time in the 1980s and I can’t see the basic thinking underlying the rules having changed, although the application may have got stricter. If I remember correctly, in manual boxes there were occasions where the train would be let down to the starting signal, and the signal would not be cleared until the train was nearly at a stand and the driver had sounded the horn. Similar arrangements were used when the train was brought to the box and stopped by a flag or lamp. Others will no doubt explain the present rules and their application.

 

[TheEdge]

Fairly often the signaller can’t clear the signal for a technical reason, such as a track-circuit failure. Even if the signaller can clear it, making the driver do something unusual and contrary to all the normal rules, hammers it in that he should be cautious and fully follow the instructions that the signaller has given him or her. That was what it was in my time in the 1980s and I can’t see the basic thinking underlying the rules having changed, although the application may have got stricter. If I remember correctly, in manual boxes there were occasions where the train would be let down to the starting signal, and the signal would not be cleared until the train was nearly at a stand and the driver had sounded the horn. Similar arrangements were used when the train was brought to the box and stopped by a flag or lamp. Others will no doubt explain the present rules and their application

A signaller should never give authority to pass a signal at danger if it can be cleared for the movement. There is a black and white list in the current rulebook of the situations where a driver can be authorised to pass a signal at danger and to "hammer home a caution" isn't one.

Your second example is a peculiarity of absolute block. If a signaller is expecting you to be brought to a stop within his station limits he will bring the train to almost a complete stop before clearing a stop signal allowing the driver to proceed to the next.

 

[Inversnecky]

There is a black and white list in the current rulebook of the situations where a driver can be authorised to pass a signal at danger and to "hammer home a caution" isn't one.

What would be the reasons, then, for permitting this movement: mainly equipment failure?

Is there a protocol for how long a driver should wait before asking, or in which circumstances (s)he should ask (so to obviate the obvious theoretical example of an impatient driver!)?

 

[Trackman]

In TS, there are some scenarios were the signalling becomes complicated and only passing a signal at danger will solve the problem. I think also in TS if the section ahead is occupied it will deny you to pass.

 

[Darandio]

A query from Train Simulator, where you can request permission from the box to pass a signal at danger on leaving a station.

If it’s safe enough to pass, why does the signaller not just change it to yellow?

Or is it assumed that the block still has a train on it, so you have to proceed with great caution (have never seen another train in TS, though)? Kind of analogous to a shunt signal permitting an engine onto a track with a stopped train just ahead?

The signal links have been placed incorrectly when the route was created.
The signal scripts have an error in them meaning even if the links are placed correctly the correct aspect won't show.
The dispatcher just cannot handle the movement.

There are a wide range of reasons why some scenarios require this.