In article , Geoff Marshall
writes
If you knew someone 'in the know' though, surely there's a way to determine
a trains number on the day from the individual carriage number which you can
see inside each car? Each set gets a new number each day (and can change
throughout the day, I'm led to believe..),

The train number for a given set should remain the same throughout the
day. There are three major exceptions to this:

(1) If a train is timetabled to stable at a depot for part of the day,
it could well be a different set that's brought out for the afternoon.
For example, the working timetable might say "train 234 start Farringdon
Sidings 0603, stable Hammersmith Depot 1012, start Hammersmith Depot
1631, stable Triangle 2250". In this case, the set that enters
Hammersmith at 1012 might not be the one that emerges at 1631. [If, on
the other hand, it says "Barking Siding 25E", it will probably be the
same set.]

(2) If a train fails in service, a replacement set may be brought out of
the depot. In this case, both sets will have carried the same number
(though only one should have it at a time for a non-trivial time[*]).

(3) If things are really messed up, the best way to get the job back
under control is to swap around some train numbers as trains are turned
back at intermediate stations. This obviously needs to be done with
great care.
[*] I can remember being on train 14 from Finchley Road to
Harrow-on-the-Hill, and another train 14 came up from the diveunder at
Wembley Park and paralleled us to Harrow; passengers were then
transferred from our train to the other one, and ours went into the
siding to return to Neasden Depot.

--
Clive D.W. Feather, writing for himself | Home:
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