lisa Wrote:
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> SD-45X was rated at 4,000 h.p. as well. I believe
> SP ended up with them and at some point rated them
> the same as the others. Extra cooling fan helped
> them in tunnels.
Per Joe Strapac's Espee Historic Diesels - Volume 12: " In spite of the huge radiator area and four fans, they developed overheating problems on their first Sierra tests. EMD quickly developed an interim fix -- airfoils that directed cooler air to the radiators. "
The " Elephant Ears " sheetmetal ducts ended up on several Espee SD-45's, while tests with the U-33-C through the tunnels & snowsheds on Donner Pass confirmed Espee's hunch that their lower radiator air intakes were more efficient. These tests with GE's put the fear into EMD, which promptly re-designed the radiator compartment into the iconic Tunnel Motor configuration.
Regarding horsepower output, EMD technical rep Preston Cook related his story of watching an Erie Lackawanna SD-45 load test, where the prime mover was screaming away at an indicated 4,200 Horsepower on their Hornell, NY., load rack. I recall that the H.P. increase involved a simple increase in the fuel rack settings and subsequent R.P.M. increase.