Generally, light rail tries to save time by quicker acceleration and deceleration. Typically, the industry recommends 3 miles per hour per second as the upper limit for passenger comfort. In other words, it would take 10 seconds to get to 30 (or ten seconds to stop from 30 mph). However, there is only a certain amount of horsepower, most light rail vehicles can’t reach 60 mph in 20 seconds. It’s more like 40 or 50 seconds.
Speeds above 50 mph are usually only practical if there is a private right of way (no grade crossings), a long distance between stations (2+ miles) and double track (single track may be practical for the last 5 miles of a line.) But, Light Rail is generally driven by costs, and grade crossings are a lot cheaper than tunnels or elevated structures. And, costs dictate that a new light rail vehicle be similar to existing ones. Which are usually 60 MPH, max.
One of the readers mentioned Karlsruhe, in Germany. They indeed run light and heavy on one set of rails.
The Stadtbahn (city trams) go in town and out to the suburbs and beyond. We were clipping along around 150 kmh (90 mph) through Rastatt to Baden-Baden. The Regiobahn (regional) do not stop at all the small stations like the S-Bahn does. They move out real well.
A side note, I rode the IC and the ICE trains a lot for the month I was in Germany. One ICE went from Frankfurt to Mannheim to Saarbrucken and then to Paris. The digital reader was showing a sustained speed of 280 kmh (175 mph) through France. That was rocking!
In Prague, and then back to Mannheim, the EC trains went along around 120 mph. Europe has been maintaining and upgrading for years, from the S-Bahn up to the ICE-5. They look to the future, while here in the US we complain about the traffic.
Munich, Hamburg, Berlin, and a few other cities have remarkable S- and U-Bahn (subway) systems. Karlsruhe Modell (German for model) have been the examples for a lot of cities getting into urban rail. It works well when politicians stay out of the way.
top speed of a normal pcc under load was about 48 mph. in additon to fast acceleration and braking, the latter 4.5 miles per hour per second using the magnetic track brakes, for emergency braking, the pcc was somewhat faster in top speed than most of the older cars it replaced. A typical double-truck birney or other four motored lighweight had four 35hp motors, while a pcc had four 55 hp motors and was just as light if not lighter. a typical double truck lightweight had a top speed of about 35 or 40 mph. then there were the vast fleets of old wood semiconvertables and convertables with only two motors, having a top speed of about 25 or 30 mph. single-truck birneys were somewhere between the two. of course cars designed for interurban service, like the bullets, the red devils, and the indiana high speeds, plus some older heavier cars like the north shore’s, were far faster, having balancing speeds of about 80 mph, and having possibilities of even faster running under the most favorable conditions.
does anyone know for certain if the interurban pcc’s, pittsburgh railways’ charleroi and washington lines, and the pacific electric, had different gearing for higher top speeds and slightly less acceleration? trucks were slightly different. the red arrow postwar lighweights, with pcc style bodies but without resilient wheels, pcc control, and with mcb type drop equalizer trucks, built by st louis in 1949, were not pccs but used the same motors. but their gearing was different and they had a 55 mph top speed.
Going 100 MPH between Mpls and St.Paul might be possible, but wouldn’t make much sense, since they’re only about 9 mi. apart (downtown to downtown). There probably aren’t going to be any nonstop trains, trains will be making several stops along the way (as they do now between DT Mpls and the Mall of America).
High speed makes more sense for interurban runs - Chicago to Milwaukee for example.
Maybe I shouldn’t butt in after all these months of inactivity on this thread, but I think in some of the posts above, a mixing of terms between what constitutes a trolley physically, where and how often it can stop, and what constitutes a proper trolley speed is muddling things a bit.
Take the Karlsruhe, Germany trolley system, which I’ve ridden. It’s a nice set-up even if the fares are a little stiff. Or take their three-car conjoined trainset cousins in Vienna*. Or take San Francisco’s Muni Metro, or the San Diego trolley, or L.A.'s east (Blue? Line–not the subway). Also take Toronto’s streetcars (I don’t know if Canadians officially use the term “trolley” car, though I feel sure they’d recognize it. The trolley is just a part of the main, the pole that gets the juice from the catenary down to the motor, which makes it a kind of living anachronism in the day of the folding pantagraph for even local traffic). If you asked most Americans what a “trolley” is, probably most of them would think first of the clang, clang, clang version. But “trolley” is this country has slowly come to mean as well “beverage cart” as on an airplane, or (and this really kills me) those rubber-tired tourist “trolleys” that are really just open-air buses in disguise, hauling out-of-towners about the downtown area. Don’t even get me started on the pseudo-Britannic use of “tram” in places like Las Vegas. *The German word for streetcar or streetcar system is “Strassenbahn,” literally “street (rail)way.” I don’t know if Siemens or ABB or the other European manufacturers have had to concoct a more modern word; but “Strassenbahn” will hold no matter how antique or modern the rolling stock is. Besides, they’ve used pantagraph co
Al, 99% of your posting is correct, but I must make one correction:
Up-to-date high speed electric locomotives, suburban mu cars, metro or subway cars, light rail cars, trams or streetcars, all today, use non-synchronous ac hysterises motors, just like the best (for heavy hauling tractive effort and high overload capacity) EMD and GE diesel locomotives. The main reason is no added maintenance for replacement of carbon brushes in the dc motors that have been familiar up to a few years ago . This is also true of modern trolleybuses and battery buses. Alstom, Semans, and Stadler (or Brown Brovori for Stadler) make these motors, also Nikki Shaaro in Japan. In the USA, the pioneer was Amtrak’s AEM-7. Of course the Acela equipment uses it, also the latest CTA, Washington, Pittsburgh, etc. equipment.
Some use this motor in an inside-out manner built into the wheel as a wheel-motor or hub-motor. This is true of some Stadler equipment and some Alsthom equipment, and makes possible a 100% low-floor streetcar or LRV with a low aisle continuing between the powered wheels. Independent suspension of each wheel or virtual truck with a low bolster pvioting under the floor are both possibilities. Las Vegas’ Max line has diesel electric articulated buses using this concept.
There is also a varient of this scheme with rotating permanent magnets instead of coils. The manufacturers of these motors are Energy Storage Systems in Derby, England, and Magnet Motor, in Pressburg, Germany. Trolleybuses and low-floor airport diesel electric buses in Europe are the main use but Energy Storage Systems makes a remote controlled tiny railroad shop switcher that is in wide use and is attemting to enter the railcar supply market.
Daveklepper, thank you for bringing my early-Metroliner standard of knowledge more up to date. Things are starting to make more sense now . . . even though what I know about electricity could still fit in Reddy Kilowatt’s left glove, I am slowly learning, in large part because of helpful advice from people like you. Thanks again for taking the time.
This reminds me that I ought to start traveling to check out the newer systems, now that I have more time. The theoretical often goes down better when it is preceded by the actual! Sadly, I don’t think I’ve been on any public transit system post-MARTA: Tri-Met, the Miami system, Mpls., Calgary, St. Louis and so on – all virgin territory --I’ve gotta to some of them!
Just for the [Hades] of it, does anyone out there know where the fastest American LRT lines are? My guess would be that the winner would have the latest technology and also the fewest stops en route – or is there a clear winner here? Something to think about
I remember the Santa Clara Valley Transit Authority (VTA) light rail trains topped out at 70 mph on some routes, notably the route down California 87 from downtown San Jose, CA.
Here in Sacramento, CA, the Regional Transit light rail usually top out at 60 mph.
One point that seems to be misunderstood about “Light Rail” is that the Light refers to the VEHICLE, NOT the weight of the rail. A LRV (Light Rail Vehicle) is a Lightweight rail VEHICLE, as opposed to a heavy rail vehicle such as a locomotive pulled train.
But again, some heavy rail vehicles are lighter than some light rail vehicles. The average Chcicago elevated or rapid transit, CTA, car weighs less than any Portland, OR or Dallas or Houston light rail car. Maybe not on a linear foot basis, because the light rail examples are three truck articulated cars and the CTA car is a 48-foot double truck car. But CTA is heavy rail because it is almost entire (now entirely except for the Brown Line) grade separated, uses equipmen not very well adaptable to street running or at least loading and loading passengers on the street, has very little if any single-car operation and runs long trains, whereas Houston and Portland and Dallas do run on the street, even if the lanes are rail or transit-only, have off-hour single-car operation, very little operation with longer than two-car trains. So it is called light rail. Typically, heavy rail equipment has end doors allowing crew, sometimes also the passengers, to pass from car to car. Typically, light rail had no more need for end doors than a bus. Many of the classic systems had both, sharing the same tracks, including Pacific Electric and Illinois Terminal. One example of heavy rail and light rail shearing the same tracks is between Cleveland Union Terminal and East 55th Street. The East-West rapid Red Line to the Airport is defined as heavy rail, even though has not generated the business to run long trains, and the Shaker Heights blue and green lines are defined as light rail, even if the actual vehicles are probably about as heavy as the red line cars. The red line loads from high platforms and the green and blue from sidewalk level with low-floor cars. Separate platforms are provided at the Terminal and at East 55th Street.
In 1903 the Brooklyn system attempted to extend an elevated line out over the streetcar tracks on Brooklyn and Queens first electric streetcar line from Cypress Street to
Sure you’re not looking at a european speedometer in kph? 120kph=72mph, still not shabby.
Back to Minneapolis-St.Paul, a direct service downtown-to-downtown might save 3-4 minutes at 100mph rather than at 55mph non-stop. Then you need another line to make local stops; and I assume there is a lot of travel demand along the line. The high-speed line could extend beyond the downtowns to numerous outlying terminals over more conventional lines with stations and bus feeder connections.
A 100mph line is the first problem. Allowing as much as 4 inches superelevation and 3 inches underbalance, a 1-degree, 5,730-foot radius curve is the minimum necessary. How much money is there to buy the property and bulldoze a new line across the two cities? You don’t want an LRV to hit or be hit by a truck at 100mph; so you need a fully grade-separated line.
The next problem is getting a compitent contractor to build the line. The Dan Ryan and O’Hare extensions were supposed to be 70mph lines that would suck all the riders off the commuter railroads. Instead, the Chicago Transit Authority rail lines deteriorated rapidly and suffered continually developing slow orders for decades. Having watched the track work progress for these extensions, I wasn’t surprised by the outcome. The current crisis is only the most recent chapter in this affair.
Another problem is that a 100mph train will take 3-4 times the power and energy than for a 55mph train.
Can anyone point the way to a recent evaluation of light rail and bus rapid transit alternative costs on an annualized basis?
At “Gopher Rail” (Univ. of MN model railroad club’s annual meet/convention) one of the guest speakers was from the company that is doing the engineering work for the light rail in the Twin Cities. IIRC he said that they had originally planned for the light rail on the Hiawatha line to go 50-55 MPH but ended up settling with 40-45 MPH because there was concern over the road/rail grade crossings…apparently Minneapolis city officials feared if the trains were going too fast, they would get to the crossings just as the crossing arms were fully down, they wanted to have a little more time to be sure the road was clear of traffic. Plus the stops are fairly close together, the train would hardly be getting up to 55 before it would have to brake for the next station.
The line between the Mpls and St Paul downtowns is going to involve some street running so it won’t be going too fast. It will probably be about like the current bus service, 20-30 minutes downtown to downtown.
The 11 mile, 15 station Central Line suggests distances between stations would allow trains to reach 55 mph. With much of the line in street reservations with frequent intersections and crosswalks, only 40-45 mph may be appropriate. Conversely, if the line eventually will be extended beyond the respective downtowns on private rights-of-way, higher speed capability, 55-65 mph, would be desirable.
The concern for gates not lowering in time ignores predictive activation technology.
People keep arguing about the mechanical capability of light rail.
You need to remember that when running near capacity, 75% of the passengers are standing. Acceleration, deceleration, and curves must take that into account.
Here in Charlotte, the Siemens Low Floor S-70s are stopping about every half mile. There are 15 stops in less than 10 miles. At the far end, they are farther apart, in city center, some of the stops are about twice the length of the train apart. That is what limits the speed.
The farther apart the stops, the faster they can go, but the farther apart the stops, the less usefull they are as urban transport. A balance between the two determines the line’s average speed.
Greeting all, I am a passegner and light rail man myself. Born and raise in chicaog but now in cali. The metrolink is ok as far in the metro but it I though california was going to start a project about light rails from her to vegas?[:-^] It would be nice to see that but I think someone said it best…people are standing on some of the inter-city trains so I can’t imagine an accident and you got people flying out the windows.[D)]
I have to take exception to the statement that the farther apart [the stops], the less useful [light rail is] as urban transport. I see the flexibility to meet changing land use and development density from urban to suburban to exurban as an advantage.
Light rail has limited capacity compared to heavy rail. LRT can meet lower travel demands in outlying lower density suburban areas without the cost of heavy rail. In some instances lrt has been built as a pre-metro and converted to rapid transit as land use densities increased.
Relatively compact urban centers impose limited and acceptable travel time penalties with surface running while providing high accessibility. The slow travel in the city center is offset by faster running in outlying areas on private rights of way. Development desities often are inadequate to generated any reasonable ridership to support closely-spaced stations. Ridership relies on bus feeder services and parking.
In an earlier posting I submitted what might be the minimal acceptabe curvature standard for a 100 mph LRT service with standing passengers, 5,730 feet. For an example, a more acceptable curve may be 8,511 feet radius. The point in that finding an alignment allowing such broad curves between Minneapolis and Saint Paul would be almost impossible.
Speed assumptions on this post have forgotten about one thing. Why not run the system on a local – express basis? Double track with 4 track express stations at a fixed distance. For example The local would pull into the outside track on a curved turnout and the express would pull straight in 1 - 1/2 minutes later. Express loads and unloads; leaves straight out. Turnout changes for the local which gets a restricting signal, then the next signal approach and the next signal clear. Proper engineering and spacing of signals could provide a very fast operation. Rush hours - transfer at each express station. Non rush - transfer at every 2nd or third station.
I can only speak of the one system I use, but during rush hour our light rail runs every 7 1/2 minutes in each direction. Trying to squeeze an express in there would be a nightmare, and would not save more than a few minutes anyway. It’s currently only 25 minutes end to end. That’s an average of about 30 MPH including stops. You couldn’t possibly save enough time to offset the cost and complexity. It’s already faster and far less aggravating than driving the road that it parallels.
