• Constant speed HEP engine?

  • Discussion of Fairbanks-Morse locomotive products. Official web site can be found here: www.fairbanksmorse.com.
Discussion of Fairbanks-Morse locomotive products. Official web site can be found here: www.fairbanksmorse.com.

Moderator: pablo

  by c604.
I thought I read a while back that FM was the first builder to have HEP (head end power) from the engine running at a constant high RPM but was used in a very limited application. Can any FM experts on here confirm that or point me in the right direction? Thanks.
  by atlpete
Don't recall the exact model designation but I believe FM's power sets for McGinnis's talgo trains on the NH and B&M utilized separate generators for train lighting/hvac, reducing horsepower down to around 1200 from 1600. This proved unpopular with the locals when the B&M units(in commuter service) would layover for the night with the engines howling at full speed. Not sure about it being the first though as GM's Aerotrain units and BLW's Train X units may have had HEP as well. see first addition Diesel Spotters Guide, back articles in both PTJ and Trains, and TLC's book NYC's Trains of the Future on the late 50's lightweight train craze. White River Productions book on the New Haven in the McGinnis Era devotes some text to the NH FM powered talgos as well. Neat Locomotives, deserved a better fate.

  by Typewriters
Interesting question. I can tell you that the GM LWT-12 (Aerotrain locomotive) and the Baldwin-Lima-Hamilton RP210 (Train X, for New York Central and New Haven) had separate generating plants for train light and heat. No reduction in prime mover power for train loads, then, on these units. (The NYC and NH units did NOT have the same auxiliary plant, though, but both of the types did have one.)

I'm somewhat of an F-M fan, and had never heard that the engine in these units ran at constant speed. Very interesting.

-Will Davis

  by EDM5970
A quick look at Kirkland's book shows that the P12-42 indeed had a constant speed power plant, running at 850 RPM. The HP was divided with 1200 for traction, 400 for HEP and 150 for parasitic loads. The HEP alternator had an output of 233 kw, 436 volts. 56.7 cycles, which I imagine was close enough to allow the use of commercial 440/60/3 heating and AC equipment.

Interesting find, as I had always thought that the GE U-34CHs that I grew up with were the first units to use constant speed engines, with changes in the traction alternator excitation used for locomotive speed control. I guess they were the first major locomotive use of that system, at least-

Somewhere I have a book, with schematics, on D/E tugs with Allis- Chalmers propulsion. The engine ran at half speed most of the time, with slower speeds controlled by field excitation. Above half speed, the excitation was maxed out and the engine RPMs determined the shaft speed. This was in the late 1930s, and I suspect that the WWII subs had similar systems, with either F-M or GM/Cleveland power.

The BLW units had a separate Maybach for HEP, and the Aerotrains had a pair of 6-71s (GM, what else-) wedged into the nose, if I'm remembering what I've read correctly.