London Banter - View Single Post

Jack Taylor · March 31st 07, 03:45 PM posted to uk.transport.london,uk.railway

wrote:
Was at London Bridge the other day platform 6 waiting for a Bedford
train watching trains pass through the platform and noticed that
signal L100 which appears as a 2 aspect but actually capable of
showing double yellow had a indicator box at side which was showing CD
this then changed to RA the signal was showing the same aspects during
the time the sign changed. anyone explain what this was etc.

The signal in question is one of the new style that uses light emitting
diodes (LEDs) for display, rather than individual lenses and bulbs.
Therefore a three-aspect traditional colour light signal can be replaced
with a single lens using LEDs. A four-aspect requires two LED displays, in
order to accommodate the two yellow aspects.

CD = close doors. Instruction to the driver of single-manned trains,
initiated by a plunger pressed by platform staff, that they are ready to
commence the departure procedure.

RA = right away. Instruction to the driver of single-manned trains,
initiated by a plunger pressed by platform staff, that the doors are closed,
all of the door open lights are extinguished and the train is clear to
depart.