# Light- and heavy-rail urban transit; why so little interoperability? **URL:** \ **Category:** Factual Questions\ **Created:** [March 17, 2014, 12:22am UTC](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883 "2014-03-17T00:22:13Z")\ **Posts on this page:** 16\ **Page:** 2
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [March 18, 2014, 4:52am UTC](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883/21 "2014-03-18T04:52:15Z")
> [@the\_diego](#): > > Light rails are often elevated, usually when the ground is too soft or loose to allow tunnelling. That’s only one reason, another being to provide grade separation as needed. The Expo line in L.A. runs mostly in a ground level right-of-way, but with many of the stations elevated. This allows the line to be grade separated at major intersections where most of the stations are found, and is facilitated by the street layout which is mostly diagonal with respect to it. Entirely elevated LRT is usually considered undesirable in residential sections, as it allows passengers to peer down into people’s back yards. ---
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [March 18, 2014, 5:16am UTC](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883/22 "2014-03-18T05:16:48Z")
> [@Mr\_Downtown](#): > > No, the reason I included Cleveland’s Red Line was the overhead catenary rather than third rail, and the small lightweight cars (especially the original Blue Birds) capable of single-car operation. > > The reason transit can’t share tracks with freight trains in the US is the enormous difference in weight and buff strength between a main line locomotive or loaded coal hopper and an aluminum-skinned transit car full of humans. A collision would be very ugly. (Though some of us feel the FRA buff-strength requirements have gone too far, and create unnecessary roadblocks for new commuter or intercity service.) So in this usage, “transit” does not include most commuter or suburban rail, correct? I ask because in these parts, Amtrak, Metrolink, and BNSF all share the same rails. I thought the main reason typical urban transit light or heavy rail vehicles couldn’t use them was the lack of electric traction. > [@](#): > > **Incubus,** CalTrain is _suburban rail_ or _regional rail,_ not \*heavy rail. \* BART is considered _heavy rail_ or _regional rail,_ thus showing how the designations overlap and depend on the nature of the network as well as the equipment used. Signal aspects frequently differ even from one railroad to another, which is why trains can’t easily use the tracks of another company and Amtrak engineers have to qualify for each railroad they run over. At 5’ guage it would be impossible for BART trains to use any tracks but their own. From what I remember of BART it does seem to be in a class of its own. Compared with urban mass transit, as in any other subway I’ve seen anywhere, BART cars seem more spacious and comfortable, with longer pitch between the rows. I don’t know how they would compare with a Bombardier bi-level passenger car as you would typically find on a typical commuter railroad. > [@](#): > > **the diego,** any train line can be elevated—though the rubber-tired trains used in Mexico City, Montreal, and Paris have trouble running outside in the snow and ice. You’d think somebody in Montreal would have said something… ---
**Author:** ![guizot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guizot/32/3636_2.png) [@guizot](https://boards.straightdope.com/u/guizot)\ **Post date:** [March 18, 2014, 6:38am UTC](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883/23 "2014-03-18T06:38:46Z")
> [@Spectre\_of\_Pithecanthropus](#): > > Entirely elevated LRT is usually considered undesirable in residential sections, as it allows passengers to peer down into people’s back yards. “Undesirable?” That’s the best part of riding the Blue Line! ---
**Author:** ![Mr\_Downtown](https://avatars.discourse-cdn.com/v4/letter/m/8e8cbc/32.png) [@Mr\_Downtown](https://boards.straightdope.com/u/Mr_Downtown)\ **Post date:** [March 19, 2014, 4:03am UTC](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883/24 "2014-03-19T04:03:53Z")
> [@Spectre\_of\_Pithecanthropus](#): > > So in this usage, “transit” does not include most commuter or suburban rail, correct? Most folks who follow transit distinguish among several types of rail operation, though there are edge cases that kind of straddle categories: **Streetcars or trams.** Nearly all street running, often in the same lanes as other traffic. Nearly always powered by overhead wires, almost all run “on sight” without special train signals. Characterized by frequent boarding locations. Muni Metro is a rare surviving example, though much of it is now more like light rail. Brand-new examples are found in Portland and Seattle; classic streetcars survive in New Orleans, Toronto, a few Scandinavian and German cities, and dozens of Eastern Bloc cities. **Light rail.** Longer, heavier vehicles whose mechanical origins are linked to streetcars/trams, and which can brake quickly enough to run in mixed traffic. Usually powered by overhead wires; new systems are usually signalized. Characterized by exclusive rights-of-way and stops at intervals averaging 1000 m or so. Since 1983, new lines have been built in dozens of North American and European cities, including San Jose and Sacramento. (A few European examples were upgraded from tramways). **Rapid transit, sometimes called “heavy rail.”** Vehicles more closely related to full-size train carriages, always operated on exclusive rights-of-way, almost never with any grade crossings, almost always signalized. The New York subway, London Underground, and Shanghai Metro are now the largest systems; LA’s Red Line is a classic example. **Interurban lines.** Think of these as “streetcars through the countryside.” Historically they were bigger cars than streetcars and ran at higher speeds (under wire), with stops every mile or so through the farmland, connecting medium-sized and large cities. The Sacramento Northern, Southern California’s Pacific Electric, the Indiana Rail Road, and the Philadelphia & Western were historic examples. The Chicago, South Shore & South Bend Rail Road is considered North America’s only surviving interurban, though you’ll still find a few in Europe. **Suburban rail or regional rail.** Descended from the commuter trains run by mainline railroads into major cities, this category can also include Washington Metro and BART because of how far they run into the suburbs, with stations spaced far apart. CalTrain and the Southland’s MetroLink and Coaster are examples. Almost always signalized. **Intercity rail.** In the US today, this means Amtrak. Historically, we might have used the term _steam railroad_ to distinguish from _street railways_ and _interurban railways._ Most of us would call all except the last category _transit._ ---
**Author:** ![VunderBob](https://avatars.discourse-cdn.com/v4/letter/v/839c29/32.png) [@VunderBob](https://boards.straightdope.com/u/VunderBob)\ **Post date:** [March 19, 2014, 11:25am UTC](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883/25 "2014-03-19T11:25:52Z")
Short answers: Heavy rail doesn’t want transit traffic on their lines because the volume can be a dispatching nightmare. Municipalities don’t want freight traffic on the transit lines if at all possible because freight on street trackage is a nightmare for the rubber tire crowd. BART was mandated to be built on 5 foot gauge (wide) specifically to keep freight off the lines. Yes, there are plenty of examples counter to my two broad points, and some have been discussed above. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [March 19, 2014, 2:04pm UTC](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883/26 "2014-03-19T14:04:09Z")
[QUOTE=VunderBob] Short answers: Heavy rail doesn’t want transit traffic on their lines because the volume can be a dispatching nightmare. [/QUOTE] This brought back memories of my days riding Amtrak’s Capitol Corridor line from Sacrament to San Francisco (via Emeryville). Much, if not most, of that line is on Union Pacific ROW, and freight is king there. Quite often, the passenger train would have to stop and wait for freight traffic. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [March 19, 2014, 11:45pm UTC](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883/27 "2014-03-19T23:45:50Z")
**Mr Downtown** , since you seem to be quite well-informed about this topic, would my assumption that Cleveland’s lines are all technically heavy rail be correct? ---
**Author:** ![Mr\_Downtown](https://avatars.discourse-cdn.com/v4/letter/m/8e8cbc/32.png) [@Mr\_Downtown](https://boards.straightdope.com/u/Mr_Downtown)\ **Post date:** [March 20, 2014, 3:42am UTC](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883/28 "2014-03-20T03:42:11Z")
No, in Cleveland only the Red Line is considered _heavy rail_ or _rapid transit._ The Shaker Heights Line, now called the Blue and Green Lines, historically was a streetcar line with high-speed running west of Shaker Square. Because of that exclusive right-of-way used for the speedy run downtown, and the much larger Breda equipment used since 1980, many folks now consider it a _light rail line._ ---
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [March 20, 2014, 5:21am UTC](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883/29 "2014-03-20T05:21:31Z")
> [@Mr\_Downtown](#): > > **Interurban lines.** Think of these as “streetcars through the countryside.” Historically they were bigger cars than streetcars and ran at higher speeds (under wire), with stops every mile or so through the farmland, connecting medium-sized and large cities. The Sacramento Northern, Southern California’s Pacific Electric, the Indiana Rail Road, and the Philadelphia & Western were historic examples. The Chicago, South Shore & South Bend Rail Road is considered North America’s only surviving interurban, though you’ll still find a few in Europe. I can only partially agree with you here. At least in the case of the PE, the longer routes, especially the ones that were more “countrified”, at least prior to post-WWII development, were served by heavier-duty trains/cars that took on some of the character of intercity passenger train coaches. For instance, look at this [Youtube clip](http://www.youtube.com/watch?v=ebboO52In1w)from the Long Beach line’s last week of operation in 1961. At about 14:46 you get brief glimpse of the interior, which looks a lot more comfortable than a typical streetcar or bus, or for that matter, the Blue Line which has replaced it today. OTOH, it must be acknowledged that, from what the clip indicates, the Blue Line today is much faster overall. As an example, the old service took well over an hour to get from DTLA to Compton Blvd.; today the Blue line makes it in half the time. The Yellow Cars of the L.A. Railway were more the urban-transport type of streetcar, with hard seats and lots of room for standing passengers. I’m not old enough to remember them well, but I do remember tracks still being in the streets perhaps until '66 or '67. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [March 20, 2014, 2:13pm UTC](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883/30 "2014-03-20T14:13:59Z")
> [@](#): > > Quoth **Mr Downtown** : > > No, in Cleveland only the Red Line is considered heavy rail or rapid transit. The Shaker Heights Line, now called the Blue and Green Lines, historically was a streetcar line with high-speed running west of Shaker Square. Because of that exclusive right-of-way used for the speedy run downtown, and the much larger Breda equipment used since 1980, many folks now consider it a light rail line. Ah, in that case, Cleveland would be an example of what the OP is asking for: Interoperable heavy and light rail. ---
**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:** [March 20, 2014, 3:44pm UTC](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883/31 "2014-03-20T15:44:44Z")
> [@Spectre\_of\_Pithecanthropus](#): > > Although, obviously, most transit operators buy their rolling stock ready made so they presumably are limited to what’s available. No one seems to have commented on this statement–which surprised me because I think it is wrong. My impression is that all light and heavy-rail urban transit (excluding buses) is custom built. Anyone? ---
**Author:** ![John\_Bredin](https://avatars.discourse-cdn.com/v4/letter/j/96bed5/32.png) [@John\_Bredin](https://boards.straightdope.com/u/John_Bredin)\ **Post date:** [March 20, 2014, 5:46pm UTC](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883/32 "2014-03-20T17:46:27Z")
> [@PastTense](#): > > No one seems to have commented on this statement–which surprised me because I think it is wrong. My impression is that all light and heavy-rail urban transit (excluding buses) is custom built. > > Anyone? I think it’s fair to say most heavy-rail/Metro/subway trains are custom because each city’s system(s) was/were built according to its own specifications. Chicago L cars are particularly short because of a lot of tight curves. New York has two different sizes of subway car due to its three pre-WWII subway systems. BART doesn’t even use standard gauge tracks (4’8.5")! IIRC, the only U.S. cities with the same metro/subway cars are Baltimore (Metro subway) and Miami (Metrorail) because they designed their systems at the same time and intentionally used the same specifications. That said, I’m fairly sure light rail and streetcars are more-or-less off-the-shelf.\* In the 1930s and ‘40s, there was even a standardized streetcar design used by various cities across the country, the PCC car. (PCC for Presidents’ Conference Committee, the “presidents” being those of the various street railway companies.) \*Yes, too many hyphens. 🙂 ---
**Author:** ![Mr\_Downtown](https://avatars.discourse-cdn.com/v4/letter/m/8e8cbc/32.png) [@Mr\_Downtown](https://boards.straightdope.com/u/Mr_Downtown)\ **Post date:** [March 21, 2014, 4:05am UTC](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883/33 "2014-03-21T04:05:42Z")
> [@VunderBob](#): > > Heavy rail doesn’t want transit traffic on their lines because the volume can be a dispatching nightmare. The subject here is public transit, not freight railroads. _Heavy rail_ is a term usually used for rapid transit trains, in distinction to _light rail_ vehicles. When freight railroads also run suburban commuter trains, as in Chicago, it’s not called _heavy rail._ > [@VunderBob](#): > > BART was mandated to be built on 5 foot gauge (wide) specifically to keep freight off the lines. No, as I explained upthread, BART’s wide gauge was simply an engineering requirement to make lightweight trains more stable when crossing the (proposed) lower level of the Golden Gate Bridge. It also made the cars roomier and more comfortable, which seemed a more important criterion at the time than being able to buy off-the-shelf equipment and hardware. > [@Chronos](#): > > Ah, in that case, Cleveland would be an example of what the OP is asking for: Interoperable heavy and light rail. Technically interoperable (same voltage and gauge), but they never run on the same track. The Red Line cars require high platforms, while the Blue and Green Line cars have steps to enter from low (street-level) platforms. The Blue and Green Line cars might well have been built wider at floor level such that they would not clear the Red Line platforms (in fact, the current cars are 11 inches narrower, so would probably require sill extenders if ever rebuilt for use on the Red Line). > [@PastTense](#): > > My impression is that all light and heavy-rail urban transit (excluding buses) is custom built. Correct, although agencies occasionally do joint orders (the Baltimore and Miami rapid transit cars were done this way). There’s a lot less customization of light-rail cars, which is one of the things that makes them less expensive. These days, many of the new North American systems order cars only slightly modified from a standard low-floor design, and occasionally cars built for one agency end up going to another for various reasons. Even in the PCC days, I don’t think any two cities had identical car orders—although as streetcar systems were converted to bus, nearly new cars got moved around. Boston bought a bunch of Dallas PCC cars, for instance, and Newark got some Minneapolis cars that ran in the Newark Subway until 2001. ---
**Author:** ![Lord\_Feldon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lord_feldon/32/341_2.png) [@Lord\_Feldon](https://boards.straightdope.com/u/Lord_Feldon)\ **Post date:** [March 21, 2014, 4:31am UTC](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883/34 "2014-03-21T04:31:33Z")
> [@Mr\_Downtown](#): > > Technically interoperable (same voltage and gauge), but they never run on the same track. The Red Line cars require high platforms, while the Blue and Green Line cars have steps to enter from low (street-level) platforms. The Blue and Green Line cars might well have been built wider at floor level such that they would not clear the Red Line platforms (in fact, the current cars are 11 inches narrower, so would probably require sill extenders if ever rebuilt for use on the Red Line). They share tracks for a little while east of Tower City. The two stations in that section have platforms with high and low ends. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [March 21, 2014, 3:16pm UTC](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883/35 "2014-03-21T15:16:36Z")
And the Blue/Green cars also all do have sill extenders on two doors per car, for loading wheelchairs. ---
**Author:** ![Mr\_Downtown](https://avatars.discourse-cdn.com/v4/letter/m/8e8cbc/32.png) [@Mr\_Downtown](https://boards.straightdope.com/u/Mr_Downtown)\ **Post date:** [March 22, 2014, 3:51am UTC](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883/36 "2014-03-22T03:51:08Z")
^Thanks. I didn’t remember the shared stations. Presumably the Red Line opened with wayside signals, which thereafter the Shaker operators had to observe. [Previous page](https://boards.straightdope.com/t/light-and-heavy-rail-urban-transit-why-so-little-interoperability/683883.md?page=1)