Two Very different yet similar ways to get ~12,000 horsepower...

[Missaberoad]

Found this Photo on Railpictures of two U50s sandwiching a GP9b and instantly thought of a very common Milwaukee Road practice of pairing two Little Joes with a GP9...

Two 5000hp U50's with a 1750hp GP9b @C855B better sit down 

http://www.railpictures.net/photo/612443/

Two 5110hp Little Joes with a 1750hp "Sputnik"

http://www.american-rails.com/images/MLWLITLJOESSIXMONTEXIT.jpg

[C855B]

... Two 5000hp U50's with a 1750hp GP9b @C855B better sit down  ...

On a TOFC train, no less. How'd they manage that? The Hueys (as in helicopters, referring to the radiator fans) proved themselves cranky from the get-go, and were sentenced assigned mostly to lines east of Cheyenne.

Reminds me I need to finish my GP9B. It's hiding somewhere on my bench.

EDIT: Looking at that picture again and noticing the PFE trailer, I am still totally puzzled how an expediter drew that [by 1968, basically crap] power. All I can figure it was like Ryan said, a heckuva way to get to 12,000HP. It must have been what was on the ready tracks when CNW dropped the hot cut in Council Bluffs and that the train was terminating at North Platte for quick reblocking for splitting between L.A. and Portland. I obviously need to pore through UPHS newsletters for info on UP's early intermodal program.

And the answer is, assuming westbound: Probably #249, symbol CNWF, or CNW Forwarder. Yes, it terminated at North Platte. Supposedly the hottest train on the RR at the time.

[Missaberoad]

Another Variation of the same consist, makes me wonder if UP had some intent behind it...

http://www.railpictures.net/photo/357772/
http://www.railpictures.net/photo/353234/

Also more U50's with pigs

http://www.railpictures.net/photo/579086/
http://www.railpictures.net/photo/539994/

I can definitely see the desire behind modeling UP!  Makes me wish my road trip along US 30 took place 20 years before I was born...

[C855B]

Possibly. A North Platte to Council Bluffs hot shuttle service, which is what these TOFC expediters were, makes a lot a sense insomuch as keeping unreliable power confined and close to major service points. I would edu-guess the GP9B in the middle was the solution to losing one of the prime movers en route - it was similar program with the 4500GTELs, a GP9 tagging along for failure relief.

I love that last shot there - U50 and three... count 'em... three SD24Bs. UP 1960s weirdness meter is nearly max'ed, just need a C855 somewhere in the shot.

[basementcalling]

Possibly. A North Platte to Council Bluffs hot shuttle service, which is what these TOFC expediters were, makes a lot a sense insomuch as keeping unreliable power confined and close to major service points. I would edu-guess the GP9B in the middle was the solution to losing one of the prime movers en route - it was similar program with the 4500GTELs, a GP9 tagging along for failure relief.

I love that last shot there - U50 and three... count 'em... three SD24Bs. UP 1960s weirdness meter is nearly max'ed, just need a C855 somewhere in the shot.

Throw in a GP30B and it is game time!

[nkalanaga]

The GP9 with the Little Joes was to get the train started.  In spite of their apparent size, the Joes were smaller, and lighter, than even a two unit boxcab set, and they had trouble starting trains.  Once the train was moving, they were faster, but the diesel was needed for extra starting tractive effort.

In later years, the roles reversed, with diesels providing most of the power, and the electrics helping on grades, both as helpers uphill, and with their regenerative braking downhill.  They could hold more than a diesel, because the energy went into the power grid, not through onboard resistors.

Also, starting a train by themselves, two Joes could draw enough current to melt the trolley wire.  The diesel helped prevent that as well.