In American railroading how come there are no dual sided diesel locomotives as there are in with electric locomotives such as the NJTransit ALP-44-46 Amtrak AEM's and GG-1's?
alloboard In American railroading how come there are no dual sided diesel locomotives as there are in with electric locomotives such as the NJTransit ALP-44-46 Amtrak AEM's and GG-1's?
That is due to the fact that, in North America, diesel locomotives are most commonly operated in multi-locomotive sets, preferebly with the first and last units in the consist facing in opposite directions so the "block" of power has a cab at either end. This is especially true for freight trains but often for passenger as well. Commuter trains often are operated with a single diesel but usually have a "cab car"; a passenger car with an operators station for the engineer at the front of the car, on the end of the train opposite the locomotive and thus can run bi-directionally without turning the engine.
Early in the process of dieselization The Central Railroad of New Jersey bought some double cab diesels for use in commuter service. This was before the use of cab cars.
http://www.american-rails.com/baldwin-dr-6-4-2000.html
(scroll down on the above page for a photograph of one of the CNJ units.)
In the case of the electric locomotives you mention they were/are most often run as single units in higher speed service where push-pull (i.e cab car on the opposite end of the train) is not desirable. They ar /were considerably more powerful than contemporary diesels and thus it is less necessary to run them in multiple unit blocks.
In Europe (and much of the rest of the world) trains are shorter and lighter and thus a single diesel locomotive is often sufficient power. Thus the dual cab arrangement makes good sense as it eliminates the need to turn the unit on a wye or turntable at the end of a run, although push-pull trains are becoming more common in those places as well...
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
Electric freight locos built in the 50s and 60s for Pennsylvania RR and Virginian RR were single-ended "road switcher" configurations and were often run in multiples. Later there were more similar locos, and even some single-ended "car-body" style electric locos built for utilities to haul coal to power plants.
I see, makes sense. Thanks for the reference link. Why are European trains lighter and shorter? Railroading is more heavy and respected there than here in the US so why would the trains be shorter?
alloboard I see, makes sense. Thanks for the reference link. Why are European trains lighter and shorter? Railroading is more heavy and respected there than here in the US so why would the trains be shorter?
There are a number of reasons why trains are shorter in Europe. One of the key reasons is speed. European trains run much faster than the trains in the US, and that´s not only passenger trains, but also freight trains. The speed of a typical intermodal unit train is 85 mph in my country, which puts a limit to its total weight for braking purposes. Another reason is frequency. European main lines see much, much more trains a day than you ever see in the US. I live within ear shot of the main line between Hamburg and Bremen. On this line, we have 300 trains a day. A long, but slow train would limit the line´s capacity considerably. Don´t forget, that passenger trains are priority trains here. No rail traveler would accept his train to be stuck behind a slow moving behemoth. Space is also an issue. Europe is much more populated than the US. If the US had the same population density as Germany, there´d be 3.2 billion folks living there. You just don´t have the space to build yards to accommodate trains 2 or 3 miles long.
Bulk commodities: Europe has great interior rivers that carry a lot of bulk commodities. In the US, the rivers mostly go the wrong direction as there are two great N-S mountain ranges. So, in the US, the RRs are oriented toward moving bulk commodities that lend themselves to long, heavy trains.
Couplers and draft gear: Big, heavy trains need strong draft arrangements. Hook and buffers can' t cut it for more than roughly 2200 tons.
Passenger/freight split: For a whole bunch of reasons, passenger service is more prevalent in Europe than here. Here, Amtrak trains have to fit in with the flow of long, heavy freight trains. There, the freight has to fit in with the short, fast passenger trains.
Interestingly, the trends in both places are converging a bit. In Europe, there are more and more bulk trains with higher strength draft arrangements that allow longer, heavier trains. They are also trying to figure out how to make a buck at loose car railroading and trying to increase the length and tonnage of the trains a bit is part of the game (particularly on the trans-Alps stuff)
Here, we are finding out that trying to reduce trip times increases asset productivity and reduces costs. It's not always about building big trains.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
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