Talk:Multiple unit

From Wikipedia, the free encyclopedia
Trains Portal
This article is within the scope of WikiProject Trains, an attempt to build a comprehensive and detailed guide to rail transport on Wikipedia. If you would like to participate, you can visit the project page, where you can join the project and/or contribute to the discussion.
See also: WikiProject Trains to do list
This article lacks sufficient references and/or adequate inline citations.
Start This article has been rated as start-Class on the quality scale. (assessment comments)
Mid This article has been rated as mid-importance within the Trains WikiProject.
This article is within the scope of WikiProject UK Railways.
High Importance: High within UK Railways WikiProject.
This article is within the scope of WikiProject Transport in Scotland.
High Importance: High within Transport in Scotland WikiProject.


To-do
list

Pending tasks for Multiple unit:

 (purge cache –  edit this list)
  • Give equal space to the US meaning for 'multiple unit' (or have a different page and cross-link)
  • Reorganize "multiple unit" pages; more detail at Talk:Multiple unit
  • Discuss coupling technologies, such as the Scharfenberg, for coupling multiple units
  • Control mechanisms
See also Wikipedia:WikiProject Trains/Todo

Contents

[edit] Budd RDCs

Were these MU-capable? Were they run in multiple very often? —Morven 21:43, Dec 28, 2004 (UTC)

They were MUs, and ran that way frequently. Some still run, but I can't say where. I rode RDCs on The Crusader and The Wall Street from Newark or Hoboken to Philadelphia with RDC MU trains. An interesting operation was the PRSL run from Philadelphia to Cape May. It left Philadelphia as a single train, then peeled off RDCs (singles usually) for Ocean City (one branch) and Wildwood (another) with the remaining train making Cape May. Reverse procedure westbound of course. -- Cecropia | explains it all ® 22:30, 28 Dec 2004 (UTC)
They should have their own article, and so should the Budd company. (anonymous, 2005-01-22, 05:06 UTC)
as indeed they now do. See: Budd Rail Diesel Car and Budd CompanyFawcett5 19:43, 22 Mar 2005 (UTC).
Just in case anyone is still wondering where they still run, R&N uses them occasionally for excursion trains. Photo at http://www.readingnorthern.com/photos/photo60.jpg of RDC in Lehigh Gorge, PA in 2000. Skabat169 17:28, 16 June 2006 (UTC)

[edit] Organization

"Multiple unit" can mean either (1) a system for controlling multiple railway vehicles from a single driving station, or (2) an independently powered rail car capable of being joined into a train controlled in this way, or (3) the resulting train. MU control can be used for locomotives, single cars (sense 2), or trams/streetcars.

Currently we have these articles (at least), with a severe shortage of links between them:

In addition there is conflicting information. "Multiple unit" says that the term diesel multiple unit (DMU) means one with a mechanical gearbox, which I have also seen called a DMMU (diesel-mechanical), while one with electric transmission is a DEMU (diesel-electric). On the other hand, "Diesel multiple units" says that the term DMU implies electric transmission. Neither one mentions the third option, hydraulic transmission (DHMU), as I believe the Budd RDC cars had.

Not only does the terminology need to be sorted out (perhaps some of the differences reflect British vs. North American usage, or other limited points of view), but I think the structure we need is:

  • multiple unit - disambiguation
  • multiple-unit control (renamed and expanded to mention locomotives)
  • multiple-unit train (acknowledging senses 2 and 3, and combining the "multiple unit" and "diesel multiple unit")

As railcars are not necessarily MU vehicles, I would leave that article substantively alone except for tidying up; the "multiple-unit train" article should link to it, though.

(anonymous, 2005-01-22, 05:06 UTC)

I concur and wish to copy this to the Trains Project Page so that others will be informed. I do however wish to add that there should be a seperate Multiple Unit Vehicle page to seperate your sense 2 from multiple-unit train. And likewise, this all makes sense for North American Railroads, but I would need input from other continents to see if this works with their systems at all. Skabat169 17:33, 16 June 2006 (UTC)

[edit] River Line in New Jersey

Since the rolling stock for the river line consists of Diesel-Electric self-propelled units, should these be referred to as "DEMU's" in the North America sub-section?TimeriderTech 05:20, 14 Apr 2005 (UTC)

[edit] Hybrid Train link?

Any reason for inclusion here? No page for Hybrid Train, re-directs to Hybrid Locomotive, no apparent relevance to Multiple unit. Probably should be removed. Keo 01:13, 30 October 2006 (UTC)

The JR hybrid train is a MU Dellarb 10:21, 6 November 2006 (UTC)


[edit] Disadvantages

I have modified the page to include disadvantages of MUs as well as their advantages. The same has been done to the locomotive page for fairness Dellarb 10:21, 6 November 2006 (UTC)


I removed the edits of Canterberry (shown below) from disadvantages since they read to me as comments, not encyclopedic content:

(The likelihood of a head-on collision is not stated, not is the assertion the the loco would act as a 'crumple zone'. In fact none of this has been substantiated or proven by means of references or citations. Canterberry 23:05, 22 May 2007 (UTC))

If people feel this is in error, discuss here before reinserting. Skabat169 19:42, 25 May 2007 (UTC)

[edit] Disputed Description

I am moving the following passage here from the article, because I dispute it.

A multiple unit train consist has the same power and traction components as a locomotive, but instead of the components concentrating on one carbody, they are spread out on each car that make up the consist. Since the power and traction components are spread out on each car, these cars can only propel themselves when they are within one complete consist, thus make them semi-permanently connected. For example, a DMU might have one car carry the prime mover and traction motors, and another carry another engine for head end power generation; an EMU might have one car carry the pantograph and transformer, and another car carry the traction motors.

If the carriages are semi-permanently connected then what you have is not a consist of multiple units, but rather a single trainset. The article lists one of the advantages of multiple units as the ability to quickly make up or break apart a consist, which would be impossible if the carriages were semi-permanently attached.DHimmelspach 04:33, 11 March 2007 (UTC)

Well, these trainsets can be multiple united together and break apart, but instead of make up or break apart by carriages, they must be made up or broke apart by trainsets. Maybe "a consist" is the wrong word to use here, but that is what I usually heard. What do you think "a consist" might mean? --Will74205 05:33, 11 March 2007 (UTC)
I just replace "consist" with "set" and place the statement back into the article, which is the intended meaning. --Will74205 05:46, 11 March 2007 (UTC)

I see you also altered the definition of multiple unit and clarified the relationship between multiple units and railcars. I think much of the dispute here involves differences in rail terminology around the globe. When I saw "semi-permanently connected" I immediately thought of something like the Bombadier Talent. The Talent features carriages that share bogies, meaning that they cannot be unhitched. Under the definition before your recent edit, the Talent would have been an extremely long railcar rather than a multiple unit. The Talent and similar products such as the Siemens Desiro occupy a gray area in rail terminology. As you have now defined multiple unit, these trains are included. I would argue that the Talent and the Desiro are modern descendants of the streamliners built just prior to and just after World War II and should occupy a separate category from multiple units. Historically, the term multiple unit arose in tram and rapid transit settings. In these settings, both then and now, train consists (US usage) or sets (UK usage) are composed of fully autonomous units that each have their own motive power. Since the Talent and the Desiro include many unpowered carriages, I think they belong in a seperate category which I call trainsets, not to be confused with train sets in UK usage. I didn't make any further edits because I don't want to get into an edit war, but I think these differences should be acknowledged. DHimmelspach 21:41, 11 March 2007 (UTC) Okay, I did go back and add a fact tag. I'm not so certain that "multiple unit trainsets" are more common than consists of autonomous units and would like a citation to confirm this fact. DHimmelspach 22:56, 11 March 2007 (UTC)

Well I add it because most EMU and DMU are trainsets by observation, perhaps it should be reworded. Should we restrict this article to describe the capability to be multiple united together, or multiple unit trains. I am not entirely happy with the current introduction either. I guess we can expand the definition of Multiple Unit to include all train cars and trainsets that can propel themselves, combined with like units, and operate from one single control cab. In this definition, Multiple Unit also covers the the common US usage on locomotives. What I meant to describe was a trainset cannot move by themselves if they are not in one complete set, such that a motor car cannot move without a power car, and vice versa. This is what I meant by "semi-permanently connected". --Will74205 23:04, 11 March 2007 (UTC) Edited --Will74205 23:15, 11 March 2007 (UTC)
My opinion - trainsets belongs in a seperate article. These are typically entire sets meant to run as a unit with little switching out of cars while MU's are generally self-contained in single units or married pairs. But this may just need further discussion and rewording. Skabat169 05:00, 9 June 2007 (UTC)

[edit] Advantages/Disadvantages section

Right now, the advantages/disadvantages section appears to be the biggest weakness. Multiple units, as defined by Wikipedia articles on the individual classes (all the articles that define train classes as multiple units), are of at least three types. The British Rail Class 319 EMU is a four-car unit that can be run in multiple (e.g. an eight-car train) but has a single motorised car in the middle, two driving cars and a trailing car. A British Rail Class 222 DEMU has all cars motorised, driving cars included. All TGV trains however, while commonly used in multiple, do still use locomotives at each end of the train. The advantages/disadvantages section has many good points but it contradicts the reality of multiple units. They don't have to have driving carriages instead of locomotives nor do they have to have every carriage motorised. All they require is that you can take two trains, join them end to end, and control both as one from a single cab. That is, unless you redefine multiple unit right across Wikipedia. Ghiraddje 14:33, 7 June 2007 (UTC)

[edit] Re-Write

Whoever re-wrote this article needs to do some revision about Wikipedia, and the need to verify all entries. This article has ZERO citations/references. All the time that has been spent on revising the article has to some extent been wasted, as the person(s) forgot to add any reference/citations. I shall review this page in one months time ... if it has not been improved then I shall recommend that it be deleted for not having any citations. I have given "fair warning" ... so act now.Sheepcot 20:52, 28 March 2007 (UTC)

Instead of blaming others for not including references, perhaps you should try to find some yourself. The problem with Multiple Unit is that its usage varies slightly in the world. So the description in the article is meant to be as inclusive as possible while stating the differences between a multiple unit and a locomotive hauled train. --Will74205 22:02, 28 March 2007 (UTC)
Listen to me. I have pointed out a problem with this article. I am not claiming to be a "lead editor" for this page, and claim glory when it gets its status improved. All I have done is indicate a flaw in the article that should have been rectified when the page was re-written. It is not up to me to include the references, I see my role as more of a project manager. Sheepcot 22:09, 28 March 2007 (UTC)
I see: a boss, not a worker. Why do assume, Sheepcot, that the plebs only contribute for "glory"? I agree wholeheartedly with Will74205. If you see a problem and can fix it, then do so (that, surely, is the true spirit of Wp). Otherwise I suggest you keep your negativist "fair warnings" to yourself. (Sorry to be rude, but some things just cannot be left unanswered.) -- Picapica 11:50, 23 June 2007 (UTC)

[edit] Multiple-unit train control

I am attempting to seperate all the discussion of MU as in train control into the article Multiple-unit train control, leaving all discussion of MU the cars for this article, EMU, and DMU. As such, I edited the article, fixing a few UK/USA problems as well. Feel free to change the other edits, but the MU Train Control removals I would prefer that they're discussed here or at Talk:Multiple-unit_train_control first. Thanks. Skabat169 05:00, 9 June 2007 (UTC)

The article still needs a major re-write. In fact, I think its now worse than before. Canterberry 12:15, 9 June 2007 (UTC)

[edit] Inaccuracy

I totally agree about the lack of sources on this page, but this comment is just downright erroneous:

Axle load - Multiple units have lighter axle loads, allowing operation on lighter tracks, where locomotives are banned, such as the Whitby line in the UK. Another side effect of this is reduced track wear, as traction forces can be provided through many axles, rather than just the four or six of a locomotive

I've been down the Esk Valley Line in the recent years in a LHCS set, and I know of other operations using such. Perhaps certain heavy locomotives are barred due to their weight, but just to say "Locomotives are banned" is dubious to say the least. If I'm hopelessy and utterly wrong, do correct me, otherwise I will remove this claim in about a week.

--79.66.115.234 (talk) 00:04, 13 March 2008 (UTC)

You can, indeed, remove the inaccurate sentence in the article if you know it's de facto wrong. -- Sameboat - 同舟 (talk) 00:50, 13 March 2008 (UTC)