London Underground signal failures
 

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.

London Underground signal failures
 

London Underground signal failures
 

London Underground signal failures
 

On Feb 15, 9:24 pm, "Richard J." wrote:
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)



At High St Ken the big problem for the platform 1 (westbound) is if if
the points fail and stay for the Inner Rail to Gloucester Road as only
Circle Line Operators sign that route. If there was a District line
train about this would have to be reversed and shunted back into
platform 2, then either up to Edgware Road or reversed to Earl's
Court.

When customers are told of a "Signal Failure" this could be either a
Signal Track Circuit Failure, Faulty Trainstop, Points Failure or even
a Signal Failure. It saves confusing people with jargon that EVERYONE
might not understand.

London Underground signal failures
 

On 16 Feb, 08:41, "chunky munky"
wrote:
On Feb 15, 9:24 pm, "Richard J." wrote:



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)

(snip)

When customers are told of a "Signal Failure" this could be either a
Signal Track Circuit Failure, Faulty Trainstop, Points Failure or even
a Signal Failure. It saves confusing people with jargon that EVERYONE
might not understand.


Perhaps the phrase used should be "signalling failure" to emphasise a
wider problem with the signalling system - I sometimes get the idea
that some passengers interpret "signal failure" in a very narrow way,
such as a bulb having blown in a colour light signal!