• U25B

  • 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 Ol' Loco Guy
Does anybody realize that the U25B was planned as a full-parallel machine ?
That accounts for the GT598 main generator-which I believe was good for
5000 A .

  by Allen Hazen
"Full-parallel". Meaning permanent parallel? no motor-transition? as with much later AC/DC designs?
Do you remember those motto placques that said "Simplify, simplify"? Was there a BIG one on the wall of the main office of GE's locomotive-design bureau?

  by mp15ac
From what I've read the EMD DDA40X was also a full parallel setup.

  by Allen Hazen
The DDA40X was a daced later, and had AC/DC transmission. By 1979, Vernon L. Smith (in his seriew of articles "The Diesel from D to L" in "Trains", subsequently re-issued as a booklet by Kalmbach) could write
"Many modern locomotives with AC generation have fixed connections with all motors in parallel, an arrangement that simplifies control and reduces slippage of the wheels when starting heavy trains."
But for a locomotive designed in the 1950s with a D.C. main generator... !!!

  by Typewriters
During the annual meeting of the Railway Fuel and Operating Officers Association in September 1962, General Electric gave a major presentation on the U25B, which was followed (per normal procedure) by an open question and answer session from the floor.

During this, a Mr. Engel, of the Chesapeake & Ohio, asked the following question: "I was wondering -- when the demonstrators were coming around, there was the fact brought to light that the locomotive may be upped to 3000 horsepower and the fact that we may be going to parallel operation."

Mr. Robert Coultas, manager of domestic sales at the time, fielded the question essentially in the negative, although he did say that he didn't hear the complete question.

However, it does give a small twinkle of support in the sense that somebody, somewhere apparently made such a statement -- that somebody apparently being a representative of General Electric, who was on board for the aforementioned demonstration tour. From this, it is difficult to tell whether the implication of parallel operation was for the later U30, or was some fragmented fact from earlier plans. The question isn't specific enough to get anything better than just the notions of 3000 HP units in late 1962, and of parallel traction motor connections.

It is true, though, that GE made the move to alternator-rectifier transmission with the relatively large GTA-9 and then later replaced it with the smaller GTA-11; perhaps the implication of "full parallel" is better suited to advance suppositions about the U30 than it is to lingering "coulda beens" from the U25, at least by this question and answer.

-Will Davis