Hi all,
I have noticed that a lot of railroad pictures from the 60’s and 70’s show locomotive consists made up of both hood units (usually GP7s/9s) and F units, but photos from the 50’s almost always show trains being pulled by one type or the other, not a mixed batch of both. So exactly when and why did this practice of conglomerating locomotive consists start? Thanks.
Initially railroads tended to buy diesels the way they bought steam engines - tailored to meet a specific need. The GP-7 and F-7 both used the same GM diesel engine, developing 1500 horsepower. So a railroad might buy a GP-7 to replace a 2-8-0 steam engine on a branchline, but an A-B-A set of F-7s to replace a 2-8-4 steam engine to haul long mainline freights.
Often the A-B-A sets would all be given the same number (sometimes with subletters like "444A / 444B / 444C") and be treated like one large engine. In part, this was to a response to railroad union's argument that each unit was a separate engine, and required an engineer and fireman, even though the units were connected together as multiple units all run from one engine.
In time, railroads realized that a "building block" idea worked better - combining engines to get the necessary horsepower to haul the tonnage of today's train. If you needed about 4000 HP, you could use three GPs, or three F-units, or a GP and two F-units, or two GPs and an F-unit. Tomorrow if you have a train needing 5500 HP, you would use four engines. Of course, every few years, EMD and Alco and others came up with more powerful engines, so three 1960's engines might pull a train that would have required four 1940's engines.
A few railroads did keep F-units together - Northern Pacific ran A-B-B-A sets of F-units up to the BN merger, and I've seen some of these engines running together in the 1970's in BN colors. Soo Line's A-units only had m.u. (multiple unit) connections on the rear, so A-units had to run at the head or end of the locomotive consist.
The Penn Central is the first RR that comes to mind when thinking of the mixed consists you describe. They not only ran consists of hood units and cab units but also ran consists from different manufacturers. Check the available online sites like RRP and Fallen Flags and you'll be surprised by the amount of engine mixing that went on, especially after the bankruptcy n 1971.
John R.
I have an Emery Goulash tape of the Wabash between Chicago and Detroit prior to the 1964 N&W merger which has F7's, GP7's, C-424's, U25b's and a Trainmaster in one lashup.
Rick Jesionowskki
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Union Pacific 428 Hi all, I have noticed that a lot of railroad pictures from the 60’s and 70’s show locomotive consists made up of both hood units (usually GP7s/9s) and F units, but photos from the 50’s almost always show trains being pulled by one type or the other, not a mixed batch of both. So exactly when and why did this practice of conglomerating locomotive consists start? Thanks.
"Exactly". Good luck with that.
I was going to say, for the general case, that it started in the early '60's.
Since UP was involved with this sort of thing, I just had a quick look in Ed Austin's "Union Pacific Diesels in Color, Volume One", and found a photo dated in 1955 of GP9 292 mated with F7B 1482C at Council Bluffs.
But then there's the "how common?" question. I think I'll still pick the early '60's for "pretty common" and "not unusual".
As for: "Why?" Because it was a good idea for efficient use of resources. It is pretty obvious if you have an ABBA set of diesels, that you really don't want to take down the whole set if one unit needs work. So if you have a GP7 available, you can just drop it in for the missing unit and get back to work (assuming, of course, that all units are coupler-equipped, as opposed to drawbarred). Of course, if you don't HAVE any GP7's, you might have to settle for just another B unit, or whatever.
Stix made similar comments earlier.
Ed
As I noted earlier, it's important to remember that an EMD F-7 and GP-7 were basically the same internally. Same diesel engine, traction motors, horsepower, etc. Just different body styles.
When GM came out with the FT, it was designed to be used in A-B sets - there was no original provision to allow couplers between the two. This meant railroads had to run either two or four engines on a train (one A-B set, or two sets A-B-B-A). However, for mainline freights the railroads needed about 4000 horsepower, which would be three units. After WW2, many railroads bought F2 and F3 separate A units, and ran them together with their existing FT A-B sets to make a three-unit A-B-A consist.
I'd guess when the GP-7 came along in 1949, it didn't take the railroads long to figure out that you could use a GP-7 instead of the single F-unit and get the same result.
wjstixAs I noted earlier, it's important to remember that an EMD F-7 and GP-7 were basically the same internally. Same diesel engine, traction motors, horsepower, etc. Just different body styles.
Sorta, maybe, almost but not exactly. The SP had problems with GP's being used as helpers derailing, but F units didn't have a problem. They traced it back to the GP's having a slightly longer distance between the truck center and coupler pulling face, creating more lateral force.
They also had quite different frame designs, the F-unit was built inside a truss where the carbody sides were structural and the GP had a "beam" underframe and the superstructure was purely sheet metal and not structural at all. It wasn't a matter of style, it was also structure.
Dave H. Painted side goes up. My website : wnbranch.com
I suppose it would depend upon whether or not you're modeling a specific prototype or modeling your own railroad, made up from your memory and fancy. I used to see all sorts of Geeps, ALCO Fs and RS's, and EMD F's running together on various roads in Wisconsin when I was a kid, back in the '50s. I don't know about FM units being able to mate with those, but I do know Baldwin diesels wouldn't MU with anything else because they used a different control system, while those I named used pneumatics.
Good luck--and have fun!
Deano
dehusman wjstix As I noted earlier, it's important to remember that an EMD F-7 and GP-7 were basically the same internally. Same diesel engine, traction motors, horsepower, etc. Just different body styles. Sorta, maybe, almost but not exactly. The SP had problems with GP's being used as helpers derailing, but F units didn't have a problem. They traced it back to the GP's having a slightly longer distance between the truck center and coupler pulling face, creating more lateral force. They also had quite different frame designs, the F-unit was built inside a truss where the carbody sides were structural and the GP had a "beam" underframe and the superstructure was purely sheet metal and not structural at all. It wasn't a matter of style, it was also structure.
I've seen photos of EMD F3's and F7's being consisted with a GP7 or a GP9 in behind the lead F unit.
How common of a practice was this?