How far apart are they spaced? In particular how quick would you pass from one to the next on a Pendo/Voyager service on the WCML?
on the London Underground, who run quite different principles for their signalling, signals on approach to a station can be much less than a train length apart.
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Surely the braking distance from full line speed is calculated based a train braking at a yellow signal to the red signal, not on sighting the yellow?
Apparently tube driving is very different in that they drive 'on sight'. No cautionary aspects. It's either green or red.
Surely the braking distance from full line speed is calculated based a train braking at a yellow signal to the red signal, not on sighting the yellow?
Apparently tube driving is very different in that they drive 'on sight'. No cautionary aspects. It's either green or red.
The 'drive on sight' comment comes from someone I know who has ridden in the cab of tube and NR trains but who isn't a driver. He said that a train could be driving at full line speed on green signals and still be able to stop if the next one was red.
I would have expected it to be off the sighting distance otherwise where would the driver reaction time come into it ?
Indeed, stand to be corrected but I think Carnforth to Settle Jn is one of, if not the longest block sections. I know we plan it as AB. That has to be 25 miles long.
Indeed, stand to be corrected but I think Carnforth to Settle Jn is one of, if not the longest block sections. I know we plan it as AB. That has to be 25 miles long.
Yes, but there are two sets of I.B. signals in between, so it's not a case of this being a 23 mile stretch of railway without any signals.The longest I know of is Blair Atholl to Dalwhinnie which is 23 miles.
I think you should take that with a pinch of salt. I cant speak for the entire underground as different systems exist on different lines, but I sign the fast lines of the Met between Harrow and Amersham, and I can assure you that it is clearly not true. Yes, there are parts where the line speed is < 40mph and you can almost certainly stop before a red after running on greens and there are sections where you will be looking at the tail lamps of the train in front of you (this also happens a lot on the busier sections of the National Rail network too)but the signalling system cannot rely on working like that. The parts of the Underground I know well have a very similar to heavy rail two, three our four aspect signalling system.
Sighting does come into the factor, if a signal is going to be a very poorly sighted signal it will be placed in a more suitable place