In message , J Lynch
writes

One would hope that such a safety critical feature is tested on a regular
basis, rather than it taking a SPAD for anyone to notice there is
something wrong.
They used to be tested on every trip both northbound and southbound, like
Leicester Sq. Is this no longer done?

A "tripcock tester" only tests that there is a tripcock arm present and in
correct alignment (at which point the tripcock tester light goes out). It
does NOT check that the tripcock will stop the train if activated, the
assumption being that if it is in the right place and alignment that it will
do the job it is provided for, if required.

To add to that. The operation is also tested every night on train prep
in the depots. The problem in this case (as in a lot of safety issues)
is it only happens when a particular set of circumstances occurs. In
this case, when the train is tripped at slow speed, usually after the
driver has been authorised to pass the signal after a failure, the SCAT
(Speed Control after Tripping) doesn't kick in. Thus allowing the train
to resume normal line speed straight away, instead of after 3 minutes.

Whilst I can totally agree with sentiments that we drivers should be
doing our job properly, these measures have been brought into place over
the years due to accidents that have occurred and people killed because
of (often) a failure of the Mk 1 Human to do their job and are thus
there to protect the travelling public and make the railways the safe
environment that they are.
--
Steve Fitzgerald has now left the building.
You will find him in London's Docklands, E16, UK
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