NYC Dopers - Subway Fire

Factual Questions
1

I read that the recent subway fire is going to put the A and C lines out of commission (or at least slowed down considerably) for up to five years. :eek:

How can this be possible in this day and age? Do the replacement parts have to be built by hand on hamster-driven machines, or what? Why are there no spare parts available? Would they not be better to rip out the whole works and convert to a newer and better technology?

This article about a subway fire at Halloween 2003 said that 200 signal wires were burnt out, but they expected to have it fixed within a week. I know the more recent incident involved relays as well as wires, but - 5 years? The articles I’ve seen are woefully short on technical details, so I’m hoping there may be some Transit dopers out there who know the Straight Dope on what’s wrong.

2

As sometimes happens, the Pit thread has become informative in parts.

3

It will take up to five years to replace everything in the signal control room, but full service is expected to be back within nine months to a year.

The short answer is that most of the equipment dates back to the 1930s and consists of extremely complex circuits and mechanisms. These things are custom-built and must now be rebuilt from scratch. More than 600 relays and circuits were destroyed in the fire, and each one has to be redesigned, rebuilt and replaced without shutting down the rest of the system.

It would be near-impossible to replace the entire signalling system without essentially rebuilding the railroad, and that would require severe disruptions in service. The A and C lines share track with the B and D for five miles in midtown, there is a complex junction with the eastern IND system at West 4th Street, and small but complex sections of track are shared with the G and F in Brooklyn, not to mention the E running on the Queens Blvd line with the F, G, R and V for ten miles or so.

Whatever you do to the A and C in order to rebuild will aversely affect all those other lines. If you make schedule changes, you have to make changes on other lines to compensate. If you change routings, you have to reroute other lines so a given section of track is not occupied beyond capacity. If you shut down the downtown local track, it not only affects A and C riders from upper Manhattan, it affects B and D riders from the Bronx as well.

In other words, a great deal of the extended timeframe comes from the complexity of repairing a system that must work 24/7 with minimal disruptions to other lines.

Another point glossed over in the pit thread is that the MTA has made significant, albeit limited progress in rebuilding signal systems. The subway has gone from being controlled by nearly a hundred switch towers all over the system to around a dozen centralized towers, and the Canarsie line has had its signalling system entirely replaced with a computerized one that in a couple years will begin to completely automate train service on that line. (The Canarsie Line (L) is isolated, not directly connected to any other revenue track, meaning it’s easier to replace the signalling system with minimal disruptions.) The Flushing (7) and Brooklyn-Queens Crosstown (G) are next, assuming the CBTC system on Canarsie is succesful. After that, the major sections of the IND and BMT would be converted in small increments, a process taking years and many, many dollars.

So, in short, it’s a very complex thing to fix.

4

[hijack]

Does the NY subway work 24/7?
I was very dissapointed when I tried to take the Paris metro at some fairly reasonable time at night, and found out that most of it (all?) shuts down for several hours!

And unless I’m misstaken, the London underground also goes to sleep at night.

5

Most of it does.

The 42nd Street shuttle stops running at midnight, but that’s easily replaced by the 7 train, and a few express trains don’t run at night, so you have to take the locals instead. There are also a few one-way expresses, like on the three-tracked Flushing line, which runs Manhattan-bound in the morning and Queens-bound in the evening.

6

Thank you.
[/hijack]

7

Yep - but only for about five hours. True 24/7 operations makes it a nightmare to deal with small niggling maintenance jobs, that can be easily dealt with in a couple of hours in an overnight shutdown. It’s a tradeoff - 24-hour operations will be more likely to have more unplanned stoppages, all other things being equal.

8

This [/url=“http://www.nycsubway.org/tech/signals/”]website provides a reasonably detailed description of how the New York City Subway signalling systems work. If you go into it a bit, you’ll see why it is a very complex process to replace the signals.

9

And for somewhat larger things, like station refurbishment, the station will simply close early during the week, and on Sundays, to allow work to be carried out then.

They try to schedule any major work at weekends.

10

Thanks all, especially to hawthorne for pointing out the Pit thread, which I had missed. I am reassured that they are now saying repairs will take months instead of years (at least to get the A line up to about 80% capacity) as my wife and I are planning to visit NYC in April, and to stay near an A line station. It’s beginning to look like this won’t be disastrous for our plans.