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Passenger Trains > Double-ended Locomotives in North America


Date: 12/09/05 15:28
Double-ended Locomotives in North America
Author: ChS7-321

This is a branch of the "new Metrolink cab-car" discussion, and relates to a post by Margaret (SPfan)

Why, besides the electrics on the NEC, are there no double-ended locomotives in North America whereas they're universal in Europe, Russia, India, China, etc, etc, etc??

Why did Amtrak think that it's such a bright idea to get the Genesis and the F59PHIs with only one cab? Ditto for the new NJT diesels, PL42s?

Also, in freight railroading...

Double-ended locos make operations much easier...don't have to have a place to wye them.



Date: 12/09/05 15:51
Re: Double-ended Locomotives in North America
Author: potb101

Probably the biggest hinderance I can see to double ended locomotives is the need to maintain two separate brake stands and the cabs that they go in. Per FRA requirements, 24 air is required to be rebuilt every 24 months, 26 air gets rebuilt every 36 months. Also, in the instance of cabs, when one piece of glass is broken, CFR requirements call for all glass to be replaced. There is nothing specifically dealing with dual cabbed units in the CFR that I can recall, but I would guess the FRA would interpret the CFR to require new glass in both cabs. I'm just guessing on that one.

For freight traffic, this is pretty much a pointless requirement anyhow, as the overwhelming percentage of North American freight trains operate either with multiple units, or are operated in such a manner that running a geep long hood forward isn't that big of a deal. So, unlike the European market, the places where a double ended locomotive can be utilized efficiently is limited to a very narrow market - basically commuter passenger trains. And the operating model for those commuter passenger trains have become accustomed for years to operating as push-pull operations. So we're talking basically about revolutionizing the market with a product that the Europeans have been accustomed to for years.



Date: 12/09/05 17:32
Re: Double-ended Locomotives in North America
Author: toledopatch

Elaborating on potb's response, how many other countries have CABLESS locomotives? Now, I'll concede they're not that common, but the only reason for their existence was to economize on maintaining the equipment -- and glass -- that comes with an operating cab.



Date: 12/09/05 19:45
Re: Double-ended Locomotives in North America
Author: RuleG

Didn't the Central Railroad of New Jersey have a few double-ended diesel locomotives?

Dave



Date: 12/09/05 19:50
Re: Double-ended Locomotives in North America
Author: toledopatch

RuleG Wrote:
-------------------------------------------------------
> Didn't the Central Railroad of New Jersey have a
> few double-ended diesel locomotives?

Indeed they did. They had short passenger hauls that required frequent run-around moves; at the time, push-pull equipment had not been introduced to the New York market.

Theirs are the only double-ended cab units I've heard of in this country.






Date: 12/09/05 20:06
Re: Double-ended Locomotives in North America
Author: MRSLIDES

toledopatch Wrote:
-------------------------------------------------------
> Elaborating on potb's response, how many other
> countries have CABLESS locomotives?


Pacific National in Australia has just received a small group of brand new B units.....based on the EMD G26C locomotive.

jcb

http://www.bensonrailphotos.com >





Date: 12/09/05 20:19
Re: Double-ended Locomotives in North America
Author: Jaap

On American consist the making and breaking of air and electric connections require craft employees. So for a locomotive run around the electrician has to disconnect the HEP , Traction and Communication jumper, the Carman disconnects the air and hangs up hoses.
After the run around a full brake test would be required since air and electric were disconnected and re connected before the train could depart.
On push pull the brake test can be performed with engineer and conductor and no craft employees.





Date: 12/09/05 21:56
Re: Double-ended Locomotives in North America
Author: airbrakegeezer

There have been several very good replies to your question already, but one point that does not seem to have been addressed is that the road-switcher type carbody, beginning with the ALCO RS-1 of the 1940's, was designed from the outset to be bi-directional. An option from all the major builders was dual control stands, but these (as noted in another post) substantially increase maintenance costs, and they also make for a very cramped cab, so not many roads ordered them (I know that a fairly large proportion of Reading Co. locos had them, and so did some N&W units, IIRC). I suspect that most enginemen who have tried it will agree that, even on a locomotive with a single AAR-type (conventional) control stand, it's not a whole lot less comfortable to run a locomotive in the "wrong" direction than it is to run it "forwards". The other point to remember is that early American diesel electrics were not powerful enough to haul a typical train with a single unit, so they were usually sold as (the EMD FT, for example), "four-unit, 5,000 HP locomotives" which were drawbar-connected and, of course, had a cab at each end -- so they were, in effect, double-ended, just as the earlier Soviet diesels consisted of two single-ended carbody units coupled back-to-back. Also remember that American electric locomotives, being more powerful than the contemporary diesels (and operating on shorter runs, with more frequent turnbacks) were much more likely to be double-ended, e.g., most PRR electrics (some will claim that P-5a's and GG-1's were not true double-enders, but I beg to differ; they had two separate cabs, even though these were not at the extreme ends of the locomotive), and just about all the box-cabs built, excepting only those (like the Milwaukee's) that were intended to always operate in MU consists.

Of course, while the FT was demonstrating, EMD found that railroads preferred couplers to drawbars, but they still sold the F types as several-unit "locomotives" with a cab at each end. Even with the much more powerful units of today, single-unit freight haulage is very uncommon, and it is easy enough to ensure that the end units of a locomotive consist face in opposite directions, so that double-enders become an unnecessary luxury.

Passenger locomotives are a whole 'nother story. The P40s and P42s are powerful enough that, in hindsight, I think Amtrak would have been smart to get them double-ended; but at the time they were specified (in the late '80's), Amtrak still ran most LD trains with enough cars to require two units, and at the time they always coupled them back-to-back, so that turning would not be required, and I guess they felt that dual cabs were not necessary. As it is now, they prefer not to uncouple and re-couple consists anyway (see other posts in this and other threads for reasons why), and end up wye-ing the whole train (the Pennsylvanian in Pittsburgh, for example).

Just a few random thoughts...



Date: 12/12/05 10:43
Re: Double-ended Locomotives in North America
Author: GBNorman

toledopatch Wrote:
-------------------------------------------------------
> RuleG Wrote:
> --------------------------------------------------
> -----
> > Didn't the Central Railroad of New Jersey
> have a
> > few double-ended diesel locomotives?
>
> Indeed they did. They had short passenger hauls
> that required frequent run-around moves; at the
> time, push-pull equipment had not been introduced
> to the New York market.
>
> Theirs are the only double-ended cab units I've
> heard of in this country.
>
>
>
>
Here we go, Mr. Patch:
http://www.insighting.co.uk/homauchchunk/2001_med.jpg




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