On 27 Aug 2005 08:50:32 -0700, "Boltar"
wrote:

Could be for detraining reasons in an emergency but they
don't need to light the whole tunnel for that. Tho it seems
to be an unofficial policy on the railways to waste
as much electricity as possible. How many times have you
been on a train in bright sunlight and the interior lights are
on when theres no tunnel for miles if at all?

Hamburg's DT4 U-Bahn units have a sensor on each end of the train to
turn the lights on just as you enter a tunnel. However, this may well
have backfired on the environmentally-friendly Germans - it takes as
much energy to start a fluorescent tube as it does to run one for
quite a period of time, as I recall.

Going back, I'm sure I remember that Merseyrail units used to have the
lights turned off until they reached Walton (for the Kirkdale tunnel),
though I can't remember when they started having them on throughout.

Neil

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Neil Williams in Milton Keynes, UK
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