On 16/08/2011 21:33, Clive wrote:
In message ,
" writes
Would they not at also at times release the brakes, using the rush of
air to let the guard know that the signal had cleared?

What about the platform repeaters, BTW?
If you got to a timing point a few minutes early then the bobby held you
until correct time. No one knowing they had a few minutes to wait stood
by the buttons ready to go so the driver normally give the train a quick
jolt. Releasing the E.P. Brakes might have done the trick if the guard
was observant, but a quick jolt was far more effective. Repeaters are
only any use where the platform is bent and the guard is at his
position, not reading a newspaper or book.

I wonder if they do this on the Island Line to this day, although
traffic volumes there are not nearly what they are/were in London.