Trainstop detection

[Deleted]

I've read in many places about the various circuits installed in trainstops which detect the position of the trainstop and extinguish the red aspect when required.

However, most of the circuits I've seen only deal with a trainstop that has failed when fully up, or failed when fully down. How does the system deal with a trainstop that goes partway down, but not all the way?

[Tom]

Both the on and off contacts will be broken, and the end result will be:
No trainstop (up) proving
Repeater for signal at caution
Repeater on same post blank
No dual aspect

A similar effect will be seen if the trainstop head is broken off and the neutralising spring comes into play.

[Deleted]

Will the red-aspect-in-rear circuit be operated then, to protect the failed trainstop?

[Tom]

That's the trainstop proving bit I was referring to. If the trainstop cannot be proved to come to the fully on position after the passage of each and every train the replacing track circuit will fail and the signal in rear will remain at danger.

[Deleted]

a text book answer tom from the signal school ;D ;D ;D