EMUs Vs Locomotives

[zebrasepta]

EMU's vs Locomotives on different Commuter Agencies
this discussion happened on the MTA forum
http://www.railroad.net/forums/viewtopi ... start=1320
Edit: What do you guys prefer? EMU's or Electric Locomotives?
My favorite is EMU's since i've ridden them over and over again on SEPTA

[Otto Vondrak]

Okay, and...?

Are you asking a question or testifying? Please reformulate your question and be more specific.

-otto-

[zebrasepta]

ok.......... here i go.........
I like EMU's better than the Locos because i live in SEPTA territory and have been used to it and most of their fleet are EMUs with Loco's pulling/pushing as expresses

[GP40 6694]

EMU's are needed for NYC area operations because of third rail pickup, but loco-hauled is clearly the way to go elsewhere.

Loco-hauled can handle more passengers per station length, run faster (up to 125mph), can be double decker, only have to have one powered unit, and can exchange equipment with diesel push-pull or DMU trailer cars.

It is my opinion that in the future, we will be moving towards two types of commuter rail service in the US (excepting MN and LIRR since they are 3rd rail).

1. Small- less than 4 cars, will use DMU's and trailer cars.

2. Big- If it needs more than 4 cars, it will be big enough to electrify with 25kV/60. Think NJT with 46a's and ML's, although most will have taller cars.

[zebrasepta]

Also due to the fact that SEPTA has alot of stops that are of short distance from each other that Locomotives would be useless to use on SEPTA
The only Locomotives SEPTA uses for passenger services are couple of AEM-7's and a ALP-44 pulling/pushing sets of Comet 1's (only 1 set in septa) and Bombers
the EMU's SEPTA runs are Silverliner II's, III's IV's and now 3 cars of V's
II's and the III's are soon to be retired
also Locomotives wear down if used on short distances?(is this correct?)
(i still like Electric locomotives though but prefer EMU's in this case)

[GP40 6694]

Also due to the fact that SEPTA has alot of stops that are of short distance from each other that Locomotives would be useless to use on SEPTA
The only Locomotives SEPTA uses for passenger services are couple of AEM-7's and a ALP-44 pulling/pushing sets of Comet 1's (only 1 set in septa) and Bombers
the EMU's SEPTA runs are Silverliner II's, III's IV's and now 3 cars of V's
II's and the III's are soon to be retired
also Locomotives wear down if used on short distances?(is this correct?)
(i still like Electric locomotives though but prefer EMU's in this case)

I think in that case, SEPTA has the fundamental problem of trying to run a subway on heavy rail...

[Allen Hazen]

EMU operation gives you motors on more axles, so better traction at low speeds, so it has operational advantages if the stations are close together. (Stations are under a thousand feet / 300 meters apart on parts of the New York Subway system, and I don't think locomotive-haulage has ever been considered there.) EMU operation has more motors, more control equipment, motors (etc) on passenger cars... So it is probably more expensive (both in equipment first cost and in maintenance). So (assuming the track structure is robust enough to support a few heavy/high axle weight vehicles), I would think that locomotive haulage would be preferred wherever operational constraints (e.g. distance between stations not too short to allow locomotives to maintain timetable) allow.

Wheelslip control -- so low-speed tractive effort -- of locomotives has improved a great deal in the past few decades, so I would think the "cross-over point" where the advantages of locomotive haulage outweigh those of EMU might have moved. So: aren't some operators (NJT?) now using locomotives in places where they used to use EMU? And is this because locomotives are now practical there but weren't when the lines (ex-DLW commuter?) were first electrified?

[GP40 6694]

I know MN and LIRR use EMU's because of the third rail pickup issues, but outside of there, it would seem EMU's really have no place. The subway isn't a fair comparison, as it's not FRA, it's on it's whole own system.