Re: Diesels

Just my estimates and guesses:
25 ton @ 150 HP @ 8 MPH = 5800 lbs te 11% adhesion
44 ton @ 380 HP @ 8 MPH = 14600 lbs te 16% adhesion
I used the figure of 8 mph to account for schedule and to keep the traction motors under the short time rating.
3.5% grade+curves+flange resistance = ~75 lbs per ton resistance
25 tonner = 5800/75 = 77 - 25 = 52 tons est ton rating
44 tonner = 14600/75 = 195 - 44 = 151 tons est capy
The U4Bs from USG (GLRR 130 & 140) were 50 ton and about 400-500 hp Cats as I remember. That was a standard export model that replaced the design of SPng 1 and sister South American 50 tonners.
Another concern would be if using a mill engine on 2 axles not to exceed the axle loading of the rail and bridges. A 44 tonner will operate on light rail just fine with 4 axles, 2 axles would need about 75# rail. Also many of these diesel-electrics only use 1 traction motor per pair of axles (side rods or chain drive to the other axle). This would lead to concerns about short time ratings at low speeds.