Hacker News Reader

Comment by innocenat | Hacker News Reader

I don't know about "shitty" but old signalling system isn't a problem if well maintained.

Japan Chuou line mentioned in the article is still on the old ATS-P system and it runs 28 train per hour. Even older ATS-S system in Osaka runs 16 train per hour on the inner track of the Tokaido line.

The NY Subway made a big fuss of CBTC and that it would allow them to run more train more reliably than their current old ATS system, which I find funny looking at various line in Japan.

In fact, CBTC in Japan is mostly planned for rural line with infrequent service so the amount of infrastructure (track circuit, etc) are reduced

View on HN

> Japan Chuou line mentioned in the article is still on the old ATS-P system and it runs 28 train per hour. Even older ATS-S system in Osaka runs 16 train per hour on the inner track of the Tokaido line.

Meanwhile in Germany: a quarter [1] of the network's signal controller stations still runs on levers, wires and semaphore signals - some of these are from the 19th century and I wish I were joking. [2]

[1] https://www.zeit.de/2019/45/deutsches-schienennetz-signalwer...

[2] http://www.stellwerke.de/formen/seite2_2.html

And yet it’s still more reliable and has higher efficiency than whatever Amtrak and the MTA are doing. It’s honestly kind of incredible just how much they have fucked up that even DB is ahead of them in efficiency.

The problem with Amtrak is that the US railway network belongs to freight train operators, and these prioritize their own freight trains over Amtrak despite the law prohibiting that [1] [2].

In Germany, most freight trains run at night because at daytime many tracks are at capacity with passenger trains.

[1] https://www.sfgate.com/opinion/article/Amtrak-has-priority-o...

[2] https://specialty-freight.com/2021/06/us-requires-railroads-...

>The problem with Amtrak is that the US railway network belongs to freight train operators

That doesn't generally apply to the Northeast Corridor though which I assume was being referenced by the mention of the MTA. That said, while it's certainly imperfect, Amtrak is actually pretty reasonable for the most part on that route. Certainly the epic delays that are fairly common on Amtrak long distance trains elsewhere are rare on that corridor outside of major infrastructure problems, such as power failures.

Not all of the NYC subway has ATS.

The current signals being replaced by CBTC date from the 1930s, and are mechanically operated. They are literally historical relics. https://www.youtube.com/watch?v=Mjx3S3UjmnA

Old signals, as installed, usually have very coarse resolution - enough so to stop trains running as close together as they otherwise would, which limits throughput

On very busy urban systems, one major advantage of CBTC is that the signalling blocks (the section of line that only one train can be in at a time) can be smaller, since the possibility of a driver failing to notice a red signal can be discounted. This increases the number of trains that can be run on the same line.

And Japan run 28 train per hour with non-CBTC block, and that's my point. You can't really get much higher than that.

Paris runs an 85 second headway on Line 14, >40TPH. https://web.archive.org/web/20061019140333/http://references...

London runs 36 TPH on the Victoria Line: https://www.londonreconnections.com/2017/ninety-second-railw...

Does Paris runs or just the CBTC capable of running? You need more than CBTC to run at 85 second headway. Loading/unloading time became huge problem at that interval.

I just checked Line 14 schedule and the most I can find is 34 train per hour, which is approx 105 second headway.

I am not saying that CBTC isn't capable of running higher interval than regular ATS and wayside signal (which is actually a very old technology), but in most case it doesn't matter. Even without moving block of CBTC, a very short static block (say, 100m) and in-cap signally should theoretically have the came capacity as CBTC.

For local trains you need your loading and unloading time to be as fast as possible anyway. People have places to be, waiting around on your trains and platforms is not on the list of things they want to do. It is even worse when they are waiting around not moving at stations they don't want to get off at. 60 seconds is the absolute longest any train door should be open for, and 45 is reasonable. (it can be pushed to 30 or even 15, but that starts to be impossible for the disabled and so not worth it)

The Victoria line in London runs up to 34 trains per hour, using CBTC: https://tfl.gov.uk/info-for/media/press-releases/2014/june/v...

Reply on news.ycombinator.com