GE U50 and GTEL informations

Allen, bogieman
Thank you both for your kind inputs.
Yes, i can imagine how strong should be the connection to the locomotive, the impressive strong shears they need to support, of course regarding the moment to start to move the train because the couplers are mounted in front of the span bolster. I've realized from some pictures the points where the shears should be applied, the coupler first, then the pivot point of the first B+B truck (outter) and then the span bolster connection point to the locomotive.
Since this locomotive was used in cargo trains (heavy), i think they were condemned to fail due to the uge maintenance costs of the trucks (i can imagine the failure of the pin points???) I can't find also if the first and second generations of the GTEL used the same solution, B+B trucks with the span bolsters.

Regards
Be safe
Bruno

Allen Hazen wrote: ↑Mon Nov 23, 2020 10:14 pm Bogieman--
Thank you! I was hoping you might comment on this.
(i) ... 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!

On EMD's new GBB truck, which I designed, and the GE 4-axle span bolster truck, the center bearing between span bolster and underframe is centered between axles 2 and 3 to equalize static axle load.

Regarding use of GE motors in the EMD GP truck (we never called it Blomberg at EMD), I am aware of it being done by modifying the transoms in the motor nose area. The bolster sits between those inboard transoms so no change to it is required. The transoms are 5" in width so the mod consists of cutting out the center portion of the transom on the motor side to remove the existing nose lugs and welding in a casting with new lugs matching the GE motor that recesses the lugs 2" into the transom. I don't recall if any change is needed at the TM air duct location on the frame adjacent to the brake hanger brackets, even with an EMD motor it's close in that area.

Dave

Allen Hazen wrote: ↑Mon Nov 23, 2020 10:49 pm Trying (unsuccessfully) to get more details on the U50's trucks, I looked at
https://utahrails.net/up/up-diesel-story-1934-1982.php
(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.

Allen, you are absolutely correct that GE motors were used on some DD35's. While the EMD parts catalog only shows one truck frame part number, digging deeper, I found there are multiple traction motor air duct part numbers listed for the DD35, some of which go with GE motors. I haven't figured out how EMD would have accomplished that, any change to the truck frame should have resulted in a new frame part number; we were always very strict about creating new numbers if form, fit, or function changed for any part. I exchanged some emails with Don Strack who confirmed that EMD assigned a model designation of 752E20A for the reconditioned motors, perhaps there were some external motor changes to make the fit easier.

Dave

Bogieman--
Thank you for your further information! Somehow (I don't remember who I got it from, let alone whether that person had obtained it legally) I have a copy of a GE document from 1971 (DF 70LC2160): a list of traction motor and generator types, apparently compiled to help the spare parts salespeople at GETS figure out what to send to a customer who wants to replace something obsolete. There are numerous "forms" (I think that is the word GE uses) of 752E traction motor, designated by adding additional numbers after the E. 752E20 is identified as a motor originally shipped as a 752A1 or 752C1, and later remanufactured to a later standard. GE doesn't seem (at that time) to have put further letters after the form number, so if EMD's records show 752E20A, the A may very well refer to some modification made by EMD in trying to fit them into the new trucks.