Two Questions

[Deleted]

well on LUL the longest track circuits i think you find are on the met line north of harrow on the hill on the amersham section of the line but i do not know any lengths i know they are very long though

1 cancel circuit for the train describer
2 part of the transmission for the train describer
3 step circuit for a programme machine
4 lock circuit for point lever lock
5 lock circuit for a signal lever lock
6 indication for a diagram
7 signal selection circuit (wot actually makes the signal go green)
8 approach control the signal
9 speed control of a signal
10 auto annoncer circuits (MIND THE GAP)
11 cancel circuit in the dot matrix (different to main t/d)
12 trip cock tester light circuit
13 siding protection (if train moves against a red signal blows traction fuse)
14 next train signs ( mile end on central as sign saying DISTRICT APPROACHING)

they are some that i can think of off the top of my head but some sites can have some site specific items



just a footnote the failing signal at west ken WC9 should now be fixed

[Tom]

Speed control trainstops (TES/TETS)
Tracklocking timers (though this is generally diversifying a bit)
Train ready to start plungers
Timing input to dot matrix
err... errr...

BTW on Jointless Track Circuits recently we have advised no more than 250m long.

[Deleted]

Good Lord!!

What about ATO/ATP-based systems?

[Deleted]

better see tom for that i have had no training on ato/atp

[tubeprune]

barney said:

Can one of our signalling gentlemen answer me two questions please? What is longest viable length for a track circuit?

I believe the maximum LUL track circuit allowed was 600m but the 250m restriction is new, isn't it?.

[Deleted]

600m sounds about right for a standard track circuit but i go along with tom for 250m on JTC systems