EMD SD9

[bpetit]

SD9s can handle 50% more tonnage than GP9s. This adds up to around 22,000lbs of tractive effort.

[BNSFdude]

I don't know if this will help, but I tried to create a performance benchmark for the SD-9 on Soldier Summit. I used 4 SD-9's to take 50 DRGW 100 ton coal hoppers and a caboose From Helper up the East Slope to Summit. Grades ranged from 0.0% to 2.3%. On the 0% grades I could slowly accelerate to 40 mph and on the 2.3% grades I dropped to 20 mph. I didn't have to use sand except when starting the train in Helper. Weather conditions were dry/overcast.

I don't know how this compares to the DRGW GP-9's with a similar consist, but I thought it might help....

In reality you should have dropped to around 10-12 MPH on that 2.3% grade and likely needed sand as even on dry rail when you are pulling anything more than 900 Amps the engines have a tendency to slip occasionally and will drop their load sometimes all the way down to 300 amps. However with the older engines, the effort is regained almost immediately to where it once was. Modern engines will drop the load and very slowly regain tractive effort.

[bpetit]

He didn't calculate his tonnage right At least that's what I do I count all my cars then I look in the bin file for the weight. Add all of that up and get the HPT rating. I also use 2240lbs or long ton instead of the short ton (2000lbs) when I convert.