I had asked whether the NY subway was able to stay open 24/7 because
trains could often/usually be rerouted if necessary:

Dave Arquati:
Because some New York lines have four tracks (for fast/slow trains) of
which one pair can be used for all services at night. So theoretically
engineering on Finchley Road - Wembley Park or Barons Court - Acton Town
needn't close the line (although I'm sure the HSE would disagree).


Robin Mayes:
You'll find only the 4 track lines continue to run 7 days a week, 24 hours a
day. The lines with only 2 tracks are shut at times for engineering works
and bus replacement services are offered. Aren't the 4 track lines more
separated than LUL / NR in most places, thus not having the engineering
staff subject to be hit by moving trains?

I wasn't aware of that when we travelled on an express line - it felt,
to be honest, like nothing so much as a Piccadilly Line train going
between Baron's Court and Acton Town, mostly travelling in between the
slow line tracks.

But only in New York have I seen a maintenance train running through
during normal working hours - it wasn't even late evening, as far as I
remember!

Thanks for the replies.
--
Annabel Smyth
http://www.amsmyth.demon.co.uk/index.html
Website updated 9 May 2004