Why don't we use bidirectional diesel locomotives in the US?

General discussion about locomotives, rolling stock, and equipment

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Re: Why don't we use bidirectional diesel locomotives in the

Postby Nasadowsk » Sat Nov 11, 2017 9:46 am

Maybe someone should make an adaptor for trains with automatic couplers?

(Nahhh... that would make too much sense)
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Re: Why don't we use bidirectional diesel locomotives in the

Postby electricron » Sat Nov 11, 2017 9:53 am

Nasadowsk wrote:Maybe someone should make an adaptor for trains with automatic couplers?
(Nahhh... that would make too much sense)


Why would that make sense? Having cabs on both ends of a locomotive isn't what is ultimately desired, having cabs on both ends of a train is. There's plenty of ways to do that, and Amtrak does it using all the ways at one place or another. None of the ways requires using an automatic coupler, or a yet to be invented adaptor for one.
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Re: Why don't we use bidirectional diesel locomotives in the

Postby TomNelligan » Sat Nov 11, 2017 1:45 pm

As a historical note, in the early years of cab units diesels, many railroads operated their F-units and such as de facto double-enders in that they were always run in A-A, A-B-A, or A-B-B-A configurations. In fact in some cases these lashups were semi-permanently coupled and never broken up. The original question is a good one, though. At the dawn of the diesel age, the large electric locomotives used by railroads like the Pennsylvania, New Haven, and New York Central were double ended so there was a US precedent for twin-cab non-steam power, but the practice didn't carry over to individual road diesels except in the sense of these cab unit assemblages.
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Re: Why don't we use bidirectional diesel locomotives in the

Postby mtuandrew » Sat Nov 11, 2017 5:08 pm

Also keep in mind that single-cab engines are effectively bidirectional (that is, not cowl or cab units.) Some are In the days before cab cars, it wasn’t uncommon for railroads to run a diesel short-end-first one direction, run around the train at the destination, and run long-end-first the other way.
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Re: Why don't we use bidirectional diesel locomotives in the

Postby bengt » Sun Nov 12, 2017 3:28 am

Nasadowsk wrote:Maybe someone should make an adaptor for trains with automatic couplers?

(Nahhh... that would make too much sense)


http://i25.photobucket.com/albums/c63/b ... /mtv/1.jpg

How to do?
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Re: Why don't we use bidirectional diesel locomotives in the

Postby Railjunkie » Sun Nov 12, 2017 9:13 am

Backshophoss wrote:Changing ends requires a brake test,however whenever you break/make connections to the brake pipe,a more extensive brake test routine is
required.



A set and release of the brakes along with a running brake test are all thats needed. General rule of thumb you turn an angle cock you need a set and release.
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Re: Why don't we use bidirectional diesel locomotives in the

Postby Noel Weaver » Sun Nov 12, 2017 2:43 pm

In so far as the New Haven was concerned the big issue with diesels was turning them or not turning them. The New Haven was an early user of road switchers, the first RS-1's that dieselized the Naugatuck Lines were the RS-1's and they did a decent job especially on the passenger trains and enabled the railroad to get rid of the turntable in Winsted early on. The biggest thing that eliminated any need for a double ended diesel was the road switcher. RS-1's came first followed by RS-2's and RS-3's. All over the place the New Haven had turntables and one by one they came out, engine facilities reduced and expenses cut. The railroad still had a fair number of Alco/GE DL-109's that if running single had to be turned so they kept some facilities for them. I read somewhere that by the mid 1950's the New Haven was down to 12 turntables but I do not think that was correct as there were still turntables in my earliest days at Stamford, New Haven, Cedar Hill (2), Maybrook, Danbury, Waterbury, Springfield, State Line and Pittsfield. This totaled 10 already and over east there was still Providence, Dover Street (Boston), New Bedford, Hyannis and probably several more. I am talking about 1956 here and a fair number of them lasted well in to the 1960's too. The Chicago North Western was a very early user of the push/pull with diesel locomotives and that saved them a bundle in switching costs. MU's also saved the electric railroads a huge amount. All of these factors meant that double ended diesel road locomotives at least in the US were not necessary. Electric locomotives were a big difference. Often electrics would travel much shorter distance between terminal points and sometimes they did not even go for servicing between trips. More than occasionally the New Haven would just send an arriving motor in Grand Central Terminal right from an inbound train to another outbound train without even going in for boiler water and the same thing sometimes happened at Penn Station as well. This was and still is one of the big advantages of using electric locomotives where they are still in use on Amtrak.
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Re: Why don't we use bidirectional diesel locomotives in the

Postby diburning » Sun Nov 12, 2017 4:40 pm

Even in Europe, most trains are double ended and/or use cab cars. The only trains that use the autocouplers are the MUs. Double ended locomotives are common, but even then, most trains either have another engine on the other end, or use a cab car. The double ended locomotives are mainly used for freight, and I'm willing to bet that passenger locomotives are built double ended to have a second life as work units or freight units.
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Re: Why don't we use bidirectional diesel locomotives in the

Postby R36 Combine Coach » Mon Nov 13, 2017 12:10 am

Do locomotives with dual cabs have two FRA cards (one in each cab) or just one per unit?
Since my friend continues to chain smoke nonstop, she is probably an Alco.
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Re: Why don't we use bidirectional diesel locomotives in the

Postby F-line to Dudley via Park » Mon Nov 13, 2017 8:55 am

diburning wrote:Even in Europe, most trains are double ended and/or use cab cars. The only trains that use the autocouplers are the MUs. Double ended locomotives are common, but even then, most trains either have another engine on the other end, or use a cab car. The double ended locomotives are mainly used for freight, and I'm willing to bet that passenger locomotives are built double ended to have a second life as work units or freight units.


The Swedes definitely use their Rc4 electrics and later derivatives in both passenger and freight service, and some passed from passenger operators to freight operators during overhaul. Freight operator Green Cargo has the largest installed base of them, second only to passenger Swedish Transport. So that's definitely why the AEM-7 came stateside dual-cabbed. Don't know if the Rc's were ever dual-used for alternating passenger or freight assignments with the same operator, though, or if they only swapped roles after being re-geared in an overhaul.

It's definitely more common worldwide with electrics than diesels, though. But that's attributable to Euroland having lots of mainline electric freight. On diesels it's simply too easy to run freight long-nose from the same cab to cover the spread of general-purpose jobs, and if it's time-sensitive enough to require running at MAS in both directions cab-forward then the job is almost certainly big/lucrative enough to require a 2-loco lash-up to begin with. Push-pull passenger service much the same...if they're changing ends it's because the scheduled layover is usually short enough that they have less time to get back on the road than it would normally take to run the loco around and thus they don't pussyfoot with the more ops-cumbersome practice. That leaves just niches...and there just aren't enough niches to create much of a worldwide market for dual-cab diesels, let alone create enough of an import market to bring that worldwide niche through all the FRA compliance hoops to sell in the U.S.
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Re: Why don't we use bidirectional diesel locomotives in the

Postby Tadman » Mon Nov 13, 2017 10:19 am

It's worth clearing up some misconceptions here.

1. There are plenty of passenger operations with transit coupler running on trackage with equipment running Janney couplers. South Shore, Metro North, Jersey Transit are the biggest examples.

2. There are coupler adapters, every Jersey Arrow and M8 carries one on the A-end. South Shore diesels carry them (as there are 15 diesels and 70+ coaches) See video: https://youtu.be/7hoMkTpSQHw

3. Someone implied there is a regulation about not mixing transit couplers on mains with freight. The above would imply this is wrong. Some members have told me that the reason NJT carries adapters on every MU is because of an FRA reg, but then why doesn't South Shore or Metra Electric carry such adapters on their MU's?

4. Although it isn't in the USA, the San Martin commuter trains in Buenos Aires are seven car sets with one double-end locomotive. All have transit couplers. At terminals, the power cuts off and runs around and the whole process is very fast. I'm not advocating this to happen in the USA, but worth noting that it does happen, and it works well.

Would it make sense for Amtrak to adopt transit couplers? The big answer is no, because it makes sense in the corridors but not on the long-distance trains. Since they share power, terminals, and rolling stock, it would be hard to make that work.
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Re: Why don't we use bidirectional diesel locomotives in the

Postby BandA » Mon Nov 13, 2017 2:17 pm

It's worth noting that competing buses & automobiles don't perform a brake test very often. I know the systems are different.
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Re: Why don't we use bidirectional diesel locomotives in the

Postby Ridgefielder » Mon Nov 13, 2017 3:50 pm

TomNelligan wrote:As a historical note, in the early years of cab units diesels, many railroads operated their F-units and such as de facto double-enders in that they were always run in A-A, A-B-A, or A-B-B-A configurations. In fact in some cases these lashups were semi-permanently coupled and never broken up. The original question is a good one, though. At the dawn of the diesel age, the large electric locomotives used by railroads like the Pennsylvania, New Haven, and New York Central were double ended so there was a US precedent for twin-cab non-steam power, but the practice didn't carry over to individual road diesels except in the sense of these cab unit assemblages.

I wouldn't confine that practice to the early years. MNRR through trains from GCT to Danbury, Poughkeepsie, and Wassaic were pulled by two FL9's coupled back-to-back until they were bumped by the GE P32AC-DMs in the early '00s. Basically the practice lasted as long as the cab unit itself.
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Re: Why don't we use bidirectional diesel locomotives in the

Postby ExCon90 » Mon Nov 13, 2017 4:53 pm

Tadman wrote:3. Someone implied there is a regulation about not mixing transit couplers on mains with freight. The above would imply this is wrong. Some members have told me that the reason NJT carries adapters on every MU is because of an FRA reg, but then why doesn't South Shore or Metra Electric carry such adapters on their MU's?

Could it be to enable a failed trainset to be rescued by a diesel from a freight railroad? (Presumably not likely on Metra Electric, but I'm sure an NS diesel might be within call on NJ Transit.)
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Re: Why don't we use bidirectional diesel locomotives in the

Postby Nasadowsk » Mon Nov 13, 2017 6:37 pm

Tadman wrote:3. Someone implied there is a regulation about not mixing transit couplers on mains with freight. The above would imply this is wrong. Some members have told me that the reason NJT carries adapters on every MU is because of an FRA reg, but then why doesn't South Shore or Metra Electric carry such adapters on their MU's?


I suspect FRA regs, which are of course printed in the CFR, thus freely searchable, are not as random as the NASCAR rulebook seems to be at times...

Either it's there or it isn't. In any case, I don't recall the LIRR's fleet carrying adapters years ago, and certainly they moved freight (the NY&A still does)
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