locomotives

[Leo_Ames]

Not only were there no GP20B's, but NYC didn't buy any GP9B's. As built, that model was exclusive to the Pennsy and Union Pacific (Although some GP9's were rebuilt later in life without cabs, including several Burlington Nothern examples). And its predecessor, the GP7B, was exclusive to the Santa Fe. 

The Central never looked behind once it tried the GP7, quickly deciding to never buy another cab unit or another booster unit. 

[16-567D3A]

   '

[cx500]

Another factor is the cost.  Having a second set of controls adds to the initial purchase price, and there is ongoing maintenance of the second cab's amenities and controls.  

In North America there have been a number of times when a major railroad has purchased road switcher style units without cabs at all as an economy measure.  New York Central and Union Pacific had GP9B and GP20B models and there may have been others.  More recent times saw the B30-7ABs on the Burlington Northern and the GP60Bs on the Santa Fe.  The service for which they were originally assigned always had several locomotives on the train that provided the necessary cab.

In the longer run the B-units can prove awkward.  Sooner or later the somewhat random distribution means eventually a terminal can end up with a cluster of them and not quite enough units with cabs to take care of all the trains. 

[mudchicken]

$$$$$$$$$$$$$$$$$$

The cost of putting dual controls on a huge fleet of locomotives is truly frightening.(thus the logic for "B" units that re-appears from time to time in North America, last w/ BN and ATSF) Common sense dictates that with multiple unit diesels that you build a locomotive consist that has locomotives that point in both directions (and where applied, you have 4 axle lighter units available for switching between terminals on lighter rail not in as good a condition as the main track, hopefully that can detach and  leave the larger power with the train on the main line or siding)

And then ther was the N&W or SOU power w/ dual controls in the same cramped cab which has faded from view.

[NorthWest]

In most places in Europe push-pull operation is used even with dual-cab locomotives.

[carnej1]

There was a single U.S railroad that did operates some double ended diesel locomotives back in the mid 20th century: The Central Railroad of New Jersey.

 http://transpressnz.blogspot.com/2012/01/jersey-central-lines-baldwin-diesel-mid.html

These were custom modified units built by the Baldwin locomotive works (a famous steam locomotive builder who for a short time competed in the Diesel electric market).

 CNJ never specified dual cabs on any susequent locomotive order so the units were unique in American service.

 IINM,there were some North American commuter operations that utilized early roadswitcher type locomotives (i.e not streamlined passenger engines) with dual control stands ,allowing them to be operated bidirectionally.

 Keep in mind that where electrification was implemented in North America dual cab electric locomotives were (and still are) quite common. Amtrak's newest electric power for use in the Northeast has this configuration:

http://en.wikipedia.org/wiki/Amtrak_Cities_Sprinter

 

[Deggesty]

Paul, I will add a little bit to what Carl said about passenger trains. Amtrak's train that runs from Oklahoma City, Oklahoma, to Fort Worth, Texas, and back every day has three cars and an engine at each end, and thus does not need to be turned. There is no turning facility close to the station in Oklahoma City, and I am sure that no one would even think of turning a train at the crossing of the Union Pacific and BNSF in Fort Worth, even though there are enough connecting tracks to make it possible. Perhaps using two engines cost Amtrak less than obtaining a cab car would have. 

[CShaveRR]

Hi, Paul, and welcome to the Forum!

I take it you're not from around here...

In North American railroading, it's relatively uncommon to pull trains with a single unit, due to the size of the trains.  And, given more than one unit, it's relatively easy to have cabs oriented in both directions at the ends of a consist.  

There may be instances where one locomotive is all that's necessary, and perhaps where a twin-cab unit might do the trick.  But those are just as easily handled by two units of lower horsepower.  If that's still too much power, one of the units can easily be taken off line.  (Keep in mind that if you do have double-ended locomotives built for such a specific use, the challenge becomes keeping them in that service...they might be treated as ordinary locomotives and become unavailable for their ideal use.)

Also, keep in mind that most locomotives here are not full-width-carbody units, so the engineer has some forward visibility no matter in which direction (s)he's facing.

As for passenger units, push-pull operations work just fine here, thanks!  If you wanted to have the locomotive on the front no matter what, that would involve moving the locomotive from one end of the train to the other several times a day, and that assumes that you have a siding right where it's necessary.  In the downtown stations here, the tracks are stub-ended, so that would involve backing the trains out of the stations to a point where the power could be run around the train, then backing the train back into the station.  Time-consuming, to say the least.  Besides that, having the locomotive staying on the end away from the terminals, you don't subject the commuters to walking down the platforms past the noisy locomotives (not to mention making everybody walk the extra locomotive length to get to their coffee, bathrooms, exit doors, or whatever!).

[tree68]

Most American freight locomotives are "hoods," as opposed to the full body cowl popular in Europe.  Thus, while inconvenient (need a set of eyes on both sides), most locomotives can be run in either direction.  Remember that many railroads ran their Diesels long hood forward by design.

This is one reason why you usually see a locomotive facing in each direction on most consists.  They generally get run in pairs, so in effect there is a cab on each end.

Locomotives with the "desktop" controls add another level of inconvenience, but that's another story.

Commuter terminals aren't usually set up to handle run-arounds, which would be required to have the locomotive lead in both directions.  And it takes time, which may or may not be available.  With a "cab car," it's just a matter of a few switches and valves and the train is ready to run in the other direction.

[PAUL DOLHY]

I always wondered why american railroads manufactures don,t make a cab on each end of the locomotive  this would save time from alternating the directions and be a saftey  concern running a engine longed nose, and in passenger trains you would elemnate push/pull passenger trains. the eurpeans are as of such?