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Approaching Semaphore Advance Starters

Current and future British signalling (UK except Northern Ireland)

Approaching Semaphore Advance Starters

Unread postby Wilkinstown » Tue Dec 5, 2017 8:52 pm

A quick question. In what circumstances can a train be allowed approach a semaphore advance starting signal controlling entry to an occupied absolute block section ? Is it sufficient for the line to be clear 440 yards in advance ?
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Re: Approaching Semaphore Advance Starters

Unread postby John Hinson » Wed Dec 6, 2017 7:30 am

It really doesn't matter if the line ahead of said signal is clear for 1 yard or 440 yards - any train drawing up to such a signal will have been brought nearly to a stand at the previous signals controlled by the same box.

The 440 yard clearing point (or whatever it is currently) is only pertinent to accepting trains through the block section.

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Re: Approaching Semaphore Advance Starters

Unread postby Wilkinstown » Tue Dec 26, 2017 8:55 am

In many instances it would have been common to have a track circuit extending from the previous signal up to a point beyond the advance starter especially where this signal was not visible from the signal box.
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