Wikipedia:Reference desk/Archives/Miscellaneous/2016 March 23

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March 23

Express subway trains

Does Wikipedia have an article for express subways trains?

New York's Line 7 has from 2 to 5 tracks and has three tracks for its express train service. During morning rush hours, the express track is used by trains bound for Manhattan. During evening rush hours, the express track is used by trains bound for Flushing.

How does the system do with the trains when they reach the terminal station? Do they send them back via the relatively less-crowded reverse direction? Or do they park the trains in the garage for the evening?

How many countries have 3 or more tracked subway or city rail express services?

Is it worthy to build such a system in other countries? Express trains are faster because they can skip minor stations. However, they can't be very fast because people are constantly walking or standing inside the train If costs and lands are not problems, I probably prefer to build two parallel lines or an elongated circular lines in order to maximize the whole system's capacity rather than to build express-capable lines. -- Toytoy (talk) 04:47, 23 March 2016 (UTC)

New Yorker here. Trains are stored in these locations whenever max capacity isn't needed. As you can see there are no "garages" in the (geometrically) inner city due to land cost so sending them back emptier cannot be avoided. At any rate rush hour is enough hours long that many trains make multiple round trips before being stowed in the parts of the geometric outer city that are linguistically inner city. Sagittarian Milky Way (talk) 06:10, 26 March 2016 (UTC)

Re: "they can't be very fast because people are constantly walking or standing inside the train", as long as it's on a smooth straightaway, the speed won't be a problem, only the acceleration and deceleration (after all, you can stand and walk on a plane, going much faster). And, since there are fewer stops, that's less of an issue. However, emergency stops would be more of a concern at high speeds. StuRat (talk) 04:54, 23 March 2016 (UTC)

"they can't be very fast because people are constantly walking or standing inside the train". The R44 subway car set a world record for speed of a subway train at 87.75 mph in 1972 but the length of the test track was insufficient to allow further acceleration. [1]. I don't know how they got permission to do that as it is illegal to make a train go over 80 mph in most of the US, including the track they were on. Sagittarian Milky Way (talk) 06:10, 26 March 2016 (UTC)

First, New York is the only city to make extensive use of express and local services on the same subway route. There are a few cities that have more limited use of 4-track subway lines with express and local trains: two relatively short sections in London (one bit with the Piccadilly and District Lines as the express and local services, one with the Metropolitan and Jubilee lines), and one in Philadelphia. In most cities the cost of 4-track routes in tunnel has meant that they have not even been considered. They are more common on commuter (suburban) railways that run above ground than on subways. In cities where the need has been felt to build a new route to relieve overcrowding on existing subway lines, generally a completely new 2-track route has been preferred, even if it is effectively an express route due to wider-spaced stations. For example, Line 14 in Paris, and for that matter the 2nd Avenue Subway in New York. Another variant of this is projecting commuter trains into central parts of the city and integrating fares with urban transit, such as the RER system, again in Paris, and S-Bahn in some German cities.

It is possible my information is out of date (it's thirty years since I lived round there) but on the London Underground the arrangement of express and stopping services continues out beyond where the Jubilee and Metropolitan lines part company at Wembley Park. It's not usually shown on the map, but there are (or were) four tracks from Wembley to Moor Park, and only some stations have platforms on the express tracks. This section is on the surface, however, not underground. --ColinFine (talk) 11:39, 23 March 2016 (UTC)

That is correct, now that you mention it; but it's still only a small part of the whole system. I should also have noted that the Piccadilly/District 4-track section is also on the surface, not underground. The Jubilee and Metropolitan use separate tunnels from Baker St. as far as Finchley Rd., but are on the surface after that. --69.159.61.172 (talk) 17:30, 23 March 2016 (UTC)

Second, as to as to the point about speed, in cities where express services do exist, they use the same trains as other lines and don't normally reach a higher top speed than locals; they just remain longer at that speed longer, giving a faster average speed. — Preceding unsigned comment added by 69.159.61.172 (talk) 05:09, 23 March 2016 (UTC)

New York express trains often do reach higher top speed than locals. Local trains are often still accelerating when they hit the brakes. Being slim as a spaghetti and on rails is a recipe for very long distances needed to get to top speed. They are powerful enough to make a standing man who's not expecting it fall over (you have to brace or hold something) and it's tiring to walk against the earlier acceleration but that's just because electric motors have max torque from at low rpm (from 0) and don't need to reach a certain rpm for max torque like gas or diesel motors. Sagittarian Milky Way (talk) 06:10, 26 March 2016 (UTC)

I was surprised to read that New York has a high - speed track which can be used by trains going in either direction. This sounds to me to be potentially lethal. Presumably the track/signal configuration is such that it is impossible for the signalman to set up a conflicting route. Does anyone have confirmation of this, and does any other railway use this system? 78.149.118.97 (talk) 14:17, 23 March 2016 (UTC)

We have Application of railway signals#Bi-directional signaling. --PalaceGuard008 (Talk) 16:46, 23 March 2016 (UTC)

Briefly, railways with bidirectional tracks are found all over the world; in some countries, such as the US and Canada, most long-distance routes are single-track. When there are multiple tracks, they may be unidirectional or bidirectional. Of course accidents are possible, but a head-on collission is just one of many types of accident and not a particularly common one. --69.159.61.172 (talk) 17:35, 23 March 2016 (UTC)

The Airport Rail Link (Bangkok) was designed to offer an alternative express service by incorporating extra tracks and platforms at the Bangkok end stations in which slow trains would wait to be passed. (Stations are farther apart at the airport end so the same doesn't happen there.) The express service is not currently offered because of a shortage of train sets.Hayttom (talk) 01:38, 27 March 2016 (UTC)