On Aug 22, 8:52 pm, Tony Chung tony@invalid wrote:
Boltar wrote:
Came back from holiday today to be greeted by the usual tube **** up.
Signal failure on the Victoria line. Something that I hadn't wondered
before is how exactly can you have a signal failure on a line thats
controlled by ATO via a leaky feeder cable? The light signals are
AFAIK there simply as extra information for drivers and arn't really
required anyway so if one fails so what? The train is control by the
ATO cable signals , not a cluster of coloured lights in the tunnel. Or
is "signal failure" just an LU catch all phrase for a computer
failure?

AFAIK the victoria is not computerised ATO. I works using mechanical
odometry and still relies on a block signalling system. It outdates
viable computers by a decade or two.

I could be wrong...

Tony

You are correct there.
The only line that use computer and non-mechanical (SSI/Relay etc)
signalling is the Central. The Jubilee does too between Green Park
and Stratford, but still uses Train Stops.
The other lines that have computers operating mechanical signalling
equipment are Bakerloo and the Circle Signalling centre (Stanmore-
Charing Cross and Wembley Park-Aldgate (Minories/Aldgate East)) and
the Piccadilly line north of Wood Green.

As to the term Signal Failure. This is a blanket term for any failure
of the signalling system (except where it is multi-site caused by the
same problem, where it is know as a Signalling System Failure). It is
mainly used where the failure is down to the Infraco or Network Rail.
Where LUL are at fault, such as a SPAD or Wrong Signal Lowered and
Accepted, it is put over as a Signalling Problem.