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.
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.
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.
You’d think somebody in Montreal would have said something…
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.
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.
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.
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.
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 clipfrom 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.
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.
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.
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.
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).
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.