• GE U50 and GTEL informations

  • Discussion of General Electric locomotive technology. Current official information can be found here: www.getransportation.com.
Discussion of General Electric locomotive technology. Current official information can be found here: www.getransportation.com.

Moderators: MEC407, AMTK84

  by lowflyer
Hello Railroad members

My name is Bruno, i'm a portuguese fan of American locomotives, specially the GE U50 and the unique GTEL.
Unfortunately due Covid i can't travel to US as i planned to visit some railway museums.
This post as the objective to ask more information's about this 2 models, i've preformed several search's over the internet and can't find technical data about this locos.
Can someone please give some help where i can find more about it? (books, sites, etc)

Be safe
  by Allen Hazen
Some basic data is available on Wikipedia (one or more serious railroad enthusiasts have done editing on some locomotive Wikipedia articles, so they are better than average.)
There is a site called thedieselshop.us which (I think the site has been reorganized at least once, but look around it and you can find things) with data tables on many locomotive models: useful, but has some errors.
If you look through the archive of this forum, you will find discussions in which a fair bit of information has been posted.
The site railroadlocomotives.blogspot.com (by the Davis brothers, who historically have been active here) also has lots of information, though I don't recall much specifically about the two models you mention.
Or: think of a specific question, and post it here! There are people who post to these railroad.net forums who know a LOT, and discussions are sometimes very informative!
(And... welcome to the forum!)
  by lowflyer
Hello Allen

Thanks for your warm welcome.
I already checked the thedieselshop.us, and they have some information indeed, but i'm looking for a little bit more detailed information, like overhaul dimensions, schematics, and in the U50 particularly, how they assembled the B+B-B+B trucks? It was one detail that make me curious.
And thanks for your suggestions, i will follow it.

  by Allen Hazen
For basic dimensions, the thedieselshop.us site probably has some numbers. (Note that published weights for locomotives... seem to be "soft" numbers. I think the contract between a railroad and a locomotive builder allows a one or two percent margin of error in how close the actual weight comes to the desired weight, and with a new, special, design like the U50 a lot of the detail design was probably done after the contract was signed. ... We had some discussion on this forum of the later U50C model: I think the upshot was that their actual weights might have been considerably above the "nominal" weights given.)

There are a couple of people who participate in Railroad.net forums (Pneudyne and Bogieman) who know a great deal about truck construction: you best bet is to have one of them get interested!

So (in an effort to tempt them to comment):
I've long assumed that the BB trucks used by GE on the "small" GTEL and (first) U50 were platforms with a pair of otherwise standard (interchangeable with what was used on many, many, Alco and GE four-axle models) below them.
??Is this right??
Each of these "platforms" would be connected to the carbody by... something pretty much like the centre pin connecting conventional trucks to carbodies?? And where was the centre of rotation for the total BB assembly? Half-way between the centre pins for the two attached B trucks is an obvious guess, but (i) if I knew more about truck dynamics I suspect I'd see a reason why the obvious guess is wrong, but (ii) I don't. ??????
Hmmm. O.k., another question about these trucks. Did they get traction motor cooling air from blowers in the carboy, through a ??single?? flexible duct, and contain ducts that then carried this air to the places where it was fed to the motors, or was something less obvious going on??

What were the BB trucks on these locomotives like on the track? I have read that, when electrification of the ex-PRR mainline between Pittsburgh and Harrisburgh was considered about the time Conrail was established, the consultants felt that a European style electric locomotive with two-axle trucks was preferable to one (like GE's E44) with conventional C trucks, because the rotational moment of inertia of the long-wheelbase three-motor truck exerted unpleasant overturning forces on the rails when going around curves. I would think the rotational moment of inertia of a BB truck might be ... big. ??????

(and I hope the naiveté of my questions attracts knowledgeable commentators!)
  by Allen Hazen
The site at thedieselshop.us seems to be undergoing changes, and the data pages for GE locomotives seem to be (I hope temporarily) unavailable. Growl.
But I looked at the page for the Alco C855, which used the same BB trucks as the U50. It gave total locomotive wheelbase (I assume this is from first axle to eighth) as 86 feet, the truck wheelbase as 23 feet, and the distance between truck renters as 44 feet.
Assume this is correct. 86-44 = 42, and half of 42 is 21 and not 23. So (lots of assumptions, but what else can I do?) it sounds as if the rotational centres of one of the BB trucks was NOT at the midpoint between the two B trucks: that from the axle closest to the end of the locomotive to the rotational centre of the BB truck was 12.5 feet, and that from that rotational centre to the axle closest to the middle of the locomotive was only 10.5 feet. (i) If I knew more about truck dynamics I might have an idea of whether this is at least plausible, but (ii) I don't.
  by lowflyer
Allen, thank you

I have looked over the internet, and i didn't find any kind information. Unfortunately here in Portugal i don't have bookstores to ask for books.
Do you have some to reference me, i can check if they are available at the amazon.
You have talked about the Alco C855, is other machine that i'm looking for, i already posted in the Alco topic, but i think since they built only the prototype, it will be very hard to find information about it.

Once more, thank you Allen.
  by lowflyer
But yes, the construction and the disposal of the trucks is amazing, i've looked some photos and seems the rotation of the inner's b truck is the connection point to the locomotive, and the outer doesn't have fisical connection with the locomotive but only with the inner truck via a span bolster. I think the same solution was used by Alco in the C855.
And yes, they are big, 85 feet long.
It was the run for the power, Alco presented a "B" unit solution to increase the overhaul power to around 16000 bhp, unfortunately the prototypes where scrapped.
  by Allen Hazen
I cited the C855 data because I couldn't find any on the U50, and the trucks should have been the same. (Both the C855 and the U50, ***I think*** , used trucks from retired/traded-in General Electric 4500 hp gas turbine locomotives. UP asked for a 5000 hp locomotive-- so as to be able to get the 15,000 hp they then thought they wanted on their trains-- and GE, which was new to the market for U.S. domestic main-line locomotives (they had been building export diesels and small locomotives for industrial use) responded by building the U50. Alco responded to the same request with the C855, EMD with the DD35, which used new, four axle in a rigid frame, trucks.
On the truck used on the U50 and the C855, neither of the B (two-axle) trucks would have been directly connected to the body of the locomotive (I assume): both were attached to the span bolster, which then was connected to the body. If the wheelbase numbers I got for the C855 are right (and the website I got them from has made mistakes in the past!), then the point of rotation for the span bolster was BETWEEN the points of attachment for the two B trucks: a bit closer to the "inboard" (closer to centre of locomotive) one than to the outboard (= closer to end of locomotive).
I believe that at least one book has been written about the Union Pacific's "Double Diesels", but I don't have it (or details about it). Perhaps someone else on the forum could provide details? And maybe look up answers to particular questions for you?
(I think I read somewhere that some of the EMD DD35 locomotives had General Electric traction motors instead of EMD ones: UP had a reasonably large fleet of first generation Alco locomotives to trade in and -- the GE 752 traction motor having been the best in the business -- undoubtedly asked EMD to re-use the motors.)
  by Allen Hazen
I've looked in my "library," and not found much. One book has construction (serial) numbers and build dates, but no useful technical information -- let me know if you want these. I have some old model railroading magazines with scale drawings of the later U50C, but nothing on the original U50.
But "The Model Railroader Cyclopedia, vol. 2: Diesel Locomotives" (published 1980 by Kalmbach, the publisher of "Trains" and "Model Railroader" magazines) has a drawing of the (first order-- not the "veranda" version) of the 4500 hp gas turbine locomotive General Electric built for the Union Pacific. Since the 4500 hp turbines were the truck "donors" for the U50, the wheelbase information is relevant. Starting from the front of the locomotive:
Front coupler pulling face to first axle: 7 feet, 1.75 inches
wheelbase of first B truck: 9 feet, 4 inches. (This is the same as on typical Alco and GE B-B locomotives. Center pivot for these trucks half way between the two axles.)
Second axle to center pivot for first span booster: 3 feet, 11.5 inches
So, from centre pivot of first B truck to centre pivot of span bolster: 8 feet, 7.5 inches.
Centre pivot of span bolster to centre pivot of second B truck: 6 feet, 8.5 inches.
Distance between centre pivots of the two span bolsters: 41 feet, 6 inches.
(So: distance between fourth and fifth axles: 18 feet, 9 inches.)
... And the same in reverse back to the pulling face of the rear coupler.
It also says the wheels were 42 inches in diameter. This was an option with GE motors -- many PA-1 Alco passenger diesels had 42 inch wheels -- but I think 40 inches was more common on freight locomotives (so, on most of the Alco and GE diesels using this style of B truck).
  by Allen Hazen
One more bit of information from the "library": Richard Steinbrenner's history of Alco, in the paragraph on the C855, mentions that GE on the U50 used trucks/span bolsters from the turbines, and that Alco's rival design also used B truck on span bolsters: it does NOT say that the C855 used trucks from retired turbines, so it may be that the C855 used NEW span bolsters. (And the wheelbases I just quoted for the Gas Turbine locomotive aren't the same as those I earlier found for the C855.)
  by Allen Hazen
On the "General Discussion (locomotives (etc))" forum, currently about 30 from the top, there is a string entitled "Eight-axle locomotives (diesel, electric, gas-turbine)". No additional information specific to the U50 (or the Alco C855), but interesting background on a wide variety of more and less analogous designs...
  by lowflyer
Hello Allen

Once more, thank you for your time giving me this amount of information, due to the pandemic, i have more time to investigate. In my usual office, the internet doesn't work yet, yes, i'm airline pilot, grounded for the time being. So i picked this free time to explore more information on my hobbie.
In this matter i'm a young student doing research, of course i picked some hard examples because they where only prototypes, only the GTEL and the u50 had some units working around, more on the GTEL.
I will follow your advices.
Once more, thank you.
  by bogieman
I, too, am interested in any details of the B+B span bolster trucks used on these locomotives. I have not found any pictures that just show the trucks or the span bolsters, I'm really curious about the connection from the span bolster to the underframe - I assume it is a typical center plate that extends into the bolster but how big in diameter and how tall I'd like to learn. Since the span bolster on the U50's and C855 includes the coupler pocket, the full buff and drag forces have to be transmitted thru the center bearing. There would appear to be a substantial moment created by the height difference between the coupler and underframe center bearing under the 1,000,000 lbs. buff load typically used for design. Because there is substantial weight that is unbalanced on the bolster due to the coupler pocket, draft gear, coupler and end plate, that is likely why the location of the B truck center bearings is different from the bolster center bearing.

Regarding using GE motors in some DD's from EMD, I can't imagine that EMD would agree to that. The GE motor requires about 2" greater distance from the axle to the nose support than the EMD motor, which would have required substantial casting changes and probably a stretched wheelbase. There is only one truck frame assembly drawing for the DD35's in the EMD Parts Catalog so I am quite sure it was not done by EMD.
  by Allen Hazen
Thank you! I was hoping you might comment on this.
(i) It hadn't occurred to me that the off-centre placement of the "centre plate" for the span bolster might be to compensate for the weight of the coupler and draft-gear, etc. Makes sense now that you mention it! ... The GE and EMD eight axle units for Brazil (all the GE and the newer EMD ones having span bolsters and four B trucks) have the couplers mounted on the locomotive frame and not on the span bolster. Do they have the centre plate for the span bolster centered between the two B trucks?
(ii) I thought I had remembered reading something about GE motors being used on EMD DD types, but it would have been a LONG time ago, and I probably misremembered. Thanks for correcting me! (EMD did, of course, use GE motors on some units in the 1960s: the GP30 and GP35 units delivered on trucks, and with motors, from Alco trade-ins. Since they used the Alco trucks, the GE motors fit. On some discussion on this or another Railroad.net forum, there was some discussion of GE's use of EMD two-axle (Blomberg) trucks on some four-axle U-series units, and the issue of the dimensions of the motor came up: as I remember it, the "EMD trucks" on these U-boats had the frames of EMD trucks from trade-ins, but mated to a new and narrower bolster to accommodated the larger motor.
Thanks again!
  by Allen Hazen
Trying (unsuccessfully) to get more details on the U50's trucks, I looked at
(part of a history of UP motive power). Locomotive types are covered, paragraph or so each, in roughly chronological order. In reference to the DD35, it says that 14 of them (DD35A 70-83) were built with GE traction motors from retired Alco FA locomotives. Either this is in error, or EMD kept no record of the truck modifications required.