On Aug 23, 11:51*pm, Roland Perry wrote:

In message , at 19:18:56 on Mon,
23 Aug 2010, Clive remarked:

LU trains in sidings often (used to) have "THIS TRAIN MUST NOT BE
MOVED" hung on the outside of the cab. *Would that be because they had
chocks fitted or something?

BR used to use metal flags on poles fitted to lamp brackets saying "NOT
TO BE MOVED" when there was a fitter or anyone else that might be out
of sight but working on an engine.

Almost every EMT train I get to St Pancras seem to have a red hexagonal
"not to be moved" sign attached above the driver's door as soon as it
arrives.

A regular feature of intercity trains at London terminals (and at the
other ends as well I think), the meaning of which I've idly pondered
many a time but never definitively deciphered.