"Dave Arquati" wrote in message
...
Annabel Smyth wrote:

On Thu, 13 May 2004 at 22:00:43, Dave Arquati wrote:


- and 24-hour LU and train services (where maintenance is presumably
carried out by pixies)

Definitely dreaming.... but what I have always wondered is how does New
York manage to run a 24-hour service, or is this because they can often
re-route trains if they want to close a section of line (very muddling
for visitors!), which we can't do in London?

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).

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?

Annabel Smyth:
what I have always wondered is how does New York manage to run a
24-hour service, or is this because they can often re-route trains
if they want to close a section of line ...

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.

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.

True. However, almost all lines do run 24/7 *except* when this sort
of closure is needed. London's tube tunnels aren't big enough for
people working there to step aside and allow a train to pass, making
various kinds of work impossible that in New York would take place
during operating hours. (However, here in Toronto the tunnels *are*
big enough, and the TTC says they still need all the overnight shutdown
time that they now have, so maybe that's not much of a factor.)

I also recall one visit to New York on a Sunday afternoon when I was
riding on a 2-track line and saw a sizeable chunk of wood, painted
yellow and striped with black electrical tape, handed to the driver --
sure enough, it was a single-line token, and the other track was closed
while work was going on on it.
--
Mark Brader, Toronto | "I don't have a life; I have a program." --the Doctor
| (Michael Piller, Star Trek: Voyager, "Tattoo")

My text in this article is in the public domain.

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

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).

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?

No, they are all scheduled to run 24/7:
http://www.mta.nyc.ny.us/nyct/service/schemain.htm

There is no regular downtime planned into the schedules, even for 2
track lines, like the L, the Manhattan part of the 7, the M North of
Broadway/Myrtle, or the J/Z in Queens. If you'd got the impression
that 2 track lines are closed a lot, it would be because the L train
is currently being upgraded to use CBTC. Of course it does happen that
the 2 track sections tend to get closed. A Passenger Service Advisory
is then posted - this certainly doesn't happen every night or indeed
every weekend.

Of course there are also a lot of 3-track sections (mostly Els, but
also the Concourse Line), the middle track of which can be used for
peak direction express (like on the 6 in the Bronx or the 7 in Queens)
as well as providing a way of keeping service running whilst MOW are
on the tracks. The only one which really doesn't get much use is the
West End express track (D train in Brooklyn) - the trains tend to be
sent over the Sea Beach (N) Line in one direction.

As far as separation between tracks goes, it's very variable. There
are sections with curtain walls, others with columns. There are of
course areas with lots of clearance and others with very little.