Question about trains: Electro-diesel / Diesel-electric?

Question

Are electro-diesel and diesel-electric trains the same thing, or two different types of trains? Going by the names at first I figured they where just two different ways of saying the same thing, but then I saw a section about diesel-electric trains and a separate section about electro-diesel trains on a locomotive's page on Wikipedia, so now I am not completely certain; although aside from this page, when searching for diesel-electric trains I have found several pages that explain how they run, while I have been able to find next to no information about how electro-diesel trains run, assuming they are in fact two different types of trains. So are they just two different ways of describing the same type of train, or two different types of trains?

Answer 1

I believe they are different ways to describe the same engine.

Answer 2

I think mt_hopper has the right idea.

The New Haven EMD FL-9 was considered an Electric-Diesel-Electric (but I guess you could call that an Electro-Diesel); it could run off its own diesel power plant or the third rail.

The New Haven was the only railroad to order and purchase FL-9's (all 60, were NH, 2000-2059) - any other railroads that came into ownership of an FL-9 got it after the Penn Central broke up its assets (including the ex-NH equipment).

While the FL-9's are still in service under CDOT (Connecticut Dept of Trans.) and Metro North, they have their third rail pick-up equipment removed, since replaced by the P32AC-DM. This is a General Electric designed unit, on the Genesis AMD-103 body. Another term for an "electro-diesel" is dual-mode.

Hopefully that helps you make some sense of the two terms. Electro-diesel being a diesel-electric that can also use an external power source, and a diesel-electric being a regular old diesel (electric). The dual-modes in the US have only been built to run off their diesel engine or a third rail - never an overhead wire (catenary).

Answer 3

I have never heard the term "electro-diesel," although UP has recently put into service new technology switcher hybrids that are battery powered when not running off the juice provided by the prime mover and main alternator, which also recharges the batteries when it is in use.

I'm not sure, as I only found out about it a week or two ago, but this may be an "electro-diesel."  Sounds logical to me, anyway.

On the other hand, there are hybrids that are electric, powered by the third rail or overhead catenary transmission systems, that are also diesel electric.  I think this more likely to be dubbed an "electro-diesel."

Wikipedia is always there, but it ain't always right.

Answer 4

Electro diesels are, as another answer has said, locos that effectively use two power sources. They were mainly designed (here in the UK) to run on the third rail system of the former Southern Railway, but with a diesel engine as back up for places which had no electricity supply. Designated Class 73, that were much more powerful when running in 'electric' mode (1600hp) as compared to diesel mode (600hp). More information and some pictures can be found here:- http://www.kentrail.co.uk/Class%2073.htm and here:-

http://www.semg.org.uk/electric/class73_... (at page 6 there are pictures of one loco in unique 'Pullman' livery)

Answer 5

Electro-diesel locomotives are made to run off off an electrical third rail, or a diesel power plant.

In the US the most common are the old FL-9 locomotive the New Haven and others bought for runs into NYC.  Steam locomotives couldn't go into Grand Central, so the trains would have to stop and change to electric locomotives.

With the advent of diesel-electrics, someone figured why not just add the switchgear to run off the electric rail and shut the diesel down?

There were two other types of locomotives so equipped.  I don't think any were made to run off of catenary, just third rail.

Some transit systems have work locomotives that can run off diesel power plants, or the third rail.  the flexibility is needed to extract trains during power failures. But they are few and usually custom built.