On 12 Mar, 00:21, wrote:
There is a sign mounted at the end of the westbound platform at Mile End. It
lights up when a Central Line train approaches, and I believe it says Train
Approaching, or something like that. It's mounted rather high up, but has no
real colour to it.

The holding light at Finchely Road looks similar to a tripcock testing
signal, only it displays the letter J when lit. It's located almost next to
the starter and is at about eye level.

Are either of those holding lights controlled from somewhere or do they
automatically light up when a train approaches?

The District Dave thread on the topic is pretty comprehensive:
http://districtdave.proboards39.com/...d =1186751545

It gives the impression they're automatic and purely informative, and
only installed in places where the driver can't see the other train.

U

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