What do you think is the best way to go with the passenger rail diesel system?

Question

Illinois and New Jersey have been going with the powerful locomotive pulling double decker cars. Its kind of slow.

In the UK they seem to like to use the DMU single level. A little more peppy.

I have seen a picture of double decker DMU in Germany.

Answer 1

As a matter of interest, most commuter systems in the UK are electrified (London, Manchester, Liverpool, Birmingham, Glasgow, for example). Also, the use of locomotive haulage on passenger trains of any description has, by and large, ceased (services into East Anglia being the main exception). It is fair to say that wherever multiple unit traction has replaced loco haulage there has been a step change in speeds, although there was loco haulage in the 100mph range in some areas. However, the main reason there are no double deck trains here is due to the small size of the UK loading gauge, the infrastructure - tunnels and bridges for example, not being large enough to accommodate the large double decked commuter trains that are seen, not only in Germany, but in other European countries like France and Holland. Many commuters would like to see double decking to obviate overcrowding on many services, but it just ain't possible!

Answer 2

I think it comes down to a matter of maintenance costs.

It might cost more to maintain a lot of DMU railcars, each with its own on-board diesel engine, vs. maintaining just a few diesel locomotives.

I don't know about other commuter railroads, but here in New York, the Metro-North commuter railroad seems to have a good experience with its General Electric dual-mode P32AC-DM Genesis II passenger locomotives, which can run on either its on-board diesel engine or through an electrified 3rd-rail.  They have been remarkably problem-free and performs well while hauling a string of Comet passenger cars.

Answer 3

The double deck trains are most common where capacity is limited, as defined by platform length.

MU trains are used for frequent stops because they typically have better acceleration, but of course cost more.  EMU are more common but of course require the catenary.

If there is enough system usage to justify it, electrification is the most effective way to increase acceleration.  I'm not sure that can be justified on all of the single track lines in NJ, however.

Incidentally, NJ Transit uses DMU on the Camden-Trenton River Line, but these have a low passenger capacity.

Answer 4

Here in California, on the ACE (Altamont Commuter Express) they use a single EMD F40PH to pull 2-6 Bombardier Bi-Level Coaches.  On CalTrain they use an EMD F40PH to pull 4-6 Bil-level Gallery cars, OR they use newer [edit] MP36PH's to pull 4-6 Bombardier Bi-Level Coaches.

Depending on the track-conditions, they get up to 79mph which is just FINE for commuter lines.

In an "Big Picture" sense, I think we should stick with that for commuter lines, but NEED to go with a 100-200 mph passenger dedicated line(s) between metropolitan areas, and a 200+ line or two transcontinental.  THOSE should be electrified.