# The Technology that Controls New York City Subways **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [July 31, 2015, 4:49pm UTC](https://boards.straightdope.com/t/the-technology-that-controls-new-york-city-subways/726660 "2015-07-31T16:49:03Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [July 31, 2015, 4:49pm UTC](https://boards.straightdope.com/t/the-technology-that-controls-new-york-city-subways/726660/1 "2015-07-31T16:49:03Z")
> [@](#): > > New York City’s subway system is a wonder of engineering—but sadly, that engineering is so old that it’s not even manufactured anymore, causing huge problems for the people who run it and anyone trying to use it. That means the MTA has built a whole shop up around trying to maintain its aging technology, and now they’re giving us a look at this underground industry. > > The MTA is currently trying to update its 100-year-old system with something called Communications-Based Train Control, which would pull it out of its current, quite dated process of controlling trains. To demonstrate just how bad it is, a video takes us deep into the systems as they stand now. At the West 4th street tower, we see all the original electromechanical equipment that’s used to control the system—including mechanical levers, a light-up control board, and ton of cloth cabling. > **[A Rare Glimpse of the Ancient Infrastructure That Controls NYC's Subway](https://gizmodo.com/a-rare-glimpse-of-the-ancient-infrastructure-that-contr-1721108174)** > > New York City’s subway system is a wonder of engineering—but sadly, that engineering is so old that it’s not even manufactured anymore, causing huge This is an interesting video. It sounds like it will take decades to upgrade the whole system. ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [July 31, 2015, 5:08pm UTC](https://boards.straightdope.com/t/the-technology-that-controls-new-york-city-subways/726660/2 "2015-07-31T17:08:35Z")
Full CBTC will never happen. Even building it on the Canarsie Line (completely isolated from the rest of the system) was a decades-long boondoggle. I do love old relay technology, though. In my apartment building they replaced the ancient elevators a couple years ago and the old controller was all built out of relay logic. They replaced a whole wall of the stuff with a single DIP-sized microcontroller. I scavenged some of the old relays from the dumpster. 🙂 ---
**Author:** ![Pork\_Rind](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pork_rind/32/111_2.png) [@Pork\_Rind](https://boards.straightdope.com/u/Pork_Rind)\ **Post date:** [July 31, 2015, 6:06pm UTC](https://boards.straightdope.com/t/the-technology-that-controls-new-york-city-subways/726660/3 "2015-07-31T18:06:01Z")
> [@friedo](#): > > I do love old relay technology, though. In my apartment building they replaced the ancient elevators a couple years ago and the old controller was all built out of relay logic. They replaced a whole wall of the stuff with a single DIP-sized microcontroller. I scavenged some of the old relays from the dumpster. 🙂 Off topic: I used to work in a building where for totally legitimate reasons I had access to an old school relay elevator controller. A really evil person that was not me no way might really enjoy commandeering the elevator and making it do unexpected things. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [July 31, 2015, 9:45pm UTC](https://boards.straightdope.com/t/the-technology-that-controls-new-york-city-subways/726660/4 "2015-07-31T21:45:46Z")
Not only is the NY subway control system horribly outdated, there’s a fair bit of it that’s poorly documented. Ten years ago, there was a fire in a tunnel that took out an interlocking control room at Chambers and it took quite a while for the engineers to reverse engineer and figure out how it was all supposed to be rebuilt. Even fighting the fire was difficult because the equipment had multiple power sources and nobody knew where they all were. ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [July 31, 2015, 10:25pm UTC](https://boards.straightdope.com/t/the-technology-that-controls-new-york-city-subways/726660/5 "2015-07-31T22:25:11Z")
> [@gotpasswords](#): > > Not only is the NY subway control system horribly outdated, there’s a fair bit of it that’s poorly documented. Ten years ago, there was a fire in a tunnel that took out an interlocking control room at Chambers and it took quite a while for the engineers to reverse engineer and figure out how it was all supposed to be rebuilt. Even fighting the fire was difficult because the equipment had multiple power sources and nobody knew where they all were. To be fair to them, once they figured it out they fixed it a _lot_ faster than they initially thought. Early estimates were that the 8th Ave Line would be crippled for a year or more, and they got things back up and running to full capacity in a few weeks. ---
**Author:** ![gaffa](https://avatars.discourse-cdn.com/v4/letter/g/e68b1a/32.png) [@gaffa](https://boards.straightdope.com/u/gaffa)\ **Post date:** [July 31, 2015, 10:42pm UTC](https://boards.straightdope.com/t/the-technology-that-controls-new-york-city-subways/726660/6 "2015-07-31T22:42:49Z")
Whenever I’m in London, and annoyed that the Tube shuts down every night for maintenance, but on the other hand, they seem to be able to keep their technology up to date. ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [July 31, 2015, 11:15pm UTC](https://boards.straightdope.com/t/the-technology-that-controls-new-york-city-subways/726660/7 "2015-07-31T23:15:11Z")
The London Tube still uses block signalling controlled by relays in most places. But they’ve taken the more sensible approach of consolidating signal rooms and computerizing the dispatch logic rather than going for full automation. ---
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [August 1, 2015, 9:14am UTC](https://boards.straightdope.com/t/the-technology-that-controls-new-york-city-subways/726660/8 "2015-08-01T09:14:00Z")
Electro-mechanical? That’s not old! I used to look in the signal box here and watch them throw the mechanical-mechanical switches. The floor-mounted levers were 3 or 4 foot long to give the operator enough mechanical advantage to physically swing the track segments. You could be further away from the control signals, but you had to be within a couple of hundred yards of the rail switch. ---
**Author:** ![usedtobe](https://avatars.discourse-cdn.com/v4/letter/u/ec9cab/32.png) [@usedtobe](https://boards.straightdope.com/u/usedtobe)\ **Post date:** [August 2, 2015, 8:51pm UTC](https://boards.straightdope.com/t/the-technology-that-controls-new-york-city-subways/726660/9 "2015-08-02T20:51:39Z")
Subways - you kids and your new-fangled stuff. San Francisco still builds cable cars. Top a hardwood block clamping onto an underground cable moving a 7 mph for antique locomotion. ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [August 2, 2015, 9:29pm UTC](https://boards.straightdope.com/t/the-technology-that-controls-new-york-city-subways/726660/10 "2015-08-02T21:29:19Z")
I remember the first time I visited San Francisco when I was a kid. Of course, we had to go ride a cable car. We got on the thing, I looked around, saw the operator man-handling his gigantic claw into a slot in the ground and said, “wow, this is a really stupid way to get around town.” ---
**Author:** ![usedtobe](https://avatars.discourse-cdn.com/v4/letter/u/ec9cab/32.png) [@usedtobe](https://boards.straightdope.com/u/usedtobe)\ **Post date:** [August 2, 2015, 11:55pm UTC](https://boards.straightdope.com/t/the-technology-that-controls-new-york-city-subways/726660/11 "2015-08-02T23:55:06Z")
Did you see the hillside sidewalks with the steps molded in? The cables were the only machine which could climb the hills until the 1950’s, when a diesel bus was tested. The result of the test is that the cables are protected in the City Charter.