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Richard J. · February 15th 07, 08:24 PM posted to uk.transport.london

wrote:
Why is it some signal failures seem to shut the line down. I was on
the Circle line yesterday when there was a signal failure at High
Street Kensington and the service was suspended. Is this because
the signal affected was for the junction so trains were not allowed
to go past it ?

I thought if the signal was stuck on red the driver was allowed to
go past it but are there special rules at junctions. If that is so
would it not be better to describe it as a points failure which to
me makes more sense why the service is suspended.

1. The Circle tends to get suspended if there are any problems with the
District or H&C, as it's the best way to help the recovery process for
the other lines.

2. Having said that, a "signal failure" at High Street Kensington,
especially on the inner rail (anti-clockwise), would be disastrous if it
prevented the points being set for the Circle.

3. It may not have been a points failure as such. It might have been a
failure in the signalling system that prevented the points from being
moved, for example if a track circuit failure made it look as if a train
was in the section that included the points. LU use "signal failure" to
mean any fault in the signalling system. This is possibly because it is
felt that passengers are more comfortable with signal failures (because
they always fail safe?) rather than track/points failures which make
people think of broken rails and derailments.
--
Richard J.
(to e-mail me, swap uk and yon in address)