"chunky munky" wrote in message
...
On Mar 29, 10:19 am, wrote:

I'm sure that it's quite easy for a train to tell if it is still in the
platform.

Blimey, how high tech do you think the tube is! :-)

Not sure, really, but I do think that it's not doing too badly if doors
won't open if the train is not properly berthed at the platform.

There are count up markers showing how far the train is out when it is
leaving a station. If a Passenger Emergency Alarm is activated whilst
within the last one then the train must stop and the PEA should be
investigated.

I know. I was just wondering, based on previous posts, if the train might
automatically brake if part of it is in the station when a PEA is activated
as it might take a driver a few seconds to realise what the alarm is and to
take appropriate reaction.

If activated between stations outside of the count up markers, then it
should continue to the next station, where it will be investigated.

On some line; Metropolitan and Circle and District are three, the
operation of the PEA will apply the brakes and operate audible and
visual warnings in the cab.

Didn't know that. I had previously thought that a PEA would never activate
emergency brakes. And I guess I am surprised that LU keep that feature. Is
it not easy to deactivate?

On some line, I believe the Jubilee to be one, the train brake will
not apply if the alarm is acknowledged, and then some lines have the
benefit of knowing what car the alarm has been operated in, so station
staff can get to the operated alarm quicker, plus some also have a
talkback so the train operator can talk with the person who has
operated, to gleam further information.

The guard light on Central line stock apparently flashes when the PEA is
activated, I think. Are those 92 or 93 rolling stock? I can't remember.