Subject:
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E/SMUs (was Re: Trans-Siberian Railway)
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Newsgroups:
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lugnet.trains
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Date:
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Mon, 20 Jun 2005 22:33:23 GMT
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Viewed:
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2698 times
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In lugnet.trains, Larry Pieniazek wrote:
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In lugnet.trains, Alexander Horoshilov wrote:
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Tim, your model is very nice. I live in Russia (and used to live in SU
before). When I was a student, I travelled with these trains a lot. Since
Russian is my native language I can help you to translate something to
English with a pleasure - just let me know, what do you need :)
I’m not a big train fan, so I do not know what “EMU” stands for.
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EMU - Electric Multiple Unit
DMU - Diesel Multiple Unit
These terms are not commonly used in the US I don’t think(1). But the idea is
that the train isn’t “locomotive hauled” but rather more than one of the
“cars” has a power truck, either straight electric or Diesel Electric or
Diesel Hydraulic or whatever. Some cars may be “trailers” though, I think
The most common DMU in the US was the Budd RDC (literally Rail Diesel Car)
although there were others. Sometimes these ran as a single unit though,
although they were built to be MU-able
What I don’t quite get with the EMU designation is what’s the difference
between an EMU and say, a string of subway cars or interurban cars (like what
South Shore Line runs, saw some in Gary on my way into Chicago this
morning)... those have traction motors in each (or at least many of the)
truck(s) too.
Perhaps some european can answer that one?
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In the UK the classification is a bit difficult to describe. The best
description is a ‘unit train’ i.e. one that runs as a fixed rake, with a driving
cab at each end and its own motive power that cannot be used seperataly. Most
passenger trains running in the UK now are technically E/DMUs, there, is little
locomotive hauled stock. The main exception I can think of is the
GNER class 91+MK4 coaches+DVT
(Driving Van Trailer) which is a push-pull. However the terms EMU and DMU are
usually reserved for the non-express units (an
HST is
technically a DMU) Most EMUs are for commuter trains (mainly on lines radiating
out from lLondon but also in other places around the country and over distances
of upto about 100 miles) On the AC overhead lines most EMUs are four cars, with
one of the centre cars powered (with pantograph) and a cab on each end car.
These are usually used in multiple DC third rail pick-up EMUs in the south-east
of London have much more variety in length and often have more distributed power
arrangement, with several cars powered. There also used to be a unpowered unit
called a 4 TC which had electrical control systems compatible with the EMUs and
was used in conjunction with them. Most DMUs serve the regions and tend to be
shorter, two or three cars. Nowadays they tend to have an engine per car to give
good enough acceleration to run on the same lines as non stopping expresses.
London Underground runs EMUs which don’t qite fit the pattern, a lot of trains
run as seven car sets, however these are often made up of a four car set with a
cab at each end and a three car set with a cab at only one and and shunters
controls at the other. I suppose this allows for maintentance.
Anyway, after that long winded explaination, I would say your subway cars were
an EMU assuming they had cab and usually worked as a rake (obviously although
‘permanently’ coupled for operational service the units can be swapped around
for maintenance).
Interestingling, in Switzerland they haven’t followed the EMU path that much,
they prefer a single (or multiple single) powered passenger carrying unit with
corridor connections that is connected to a rake of cars with cab on the last
one (steuerwagen), forming a push-pull train (pendelzug), this of course allows
more flexibility to allow for different traffic loadings. while giving the
operational advantages of an EMU.
Tim
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Message is in Reply To:
 | | Re: Trans-Siberian Railway
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| (...) EMU - Electric Multiple Unit DMU - Diesel Multiple Unit These terms are not commonly used in the US I don't think(1). But the idea is that the train isn't "locomotive hauled" but rather more than one of the "cars" has a power truck, either (...) (19 years ago, 20-Jun-05, to lugnet.trains, FTX)
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