And bc I feel like I have to, fake lore on the Berkshire.
The Pennsylvania Railroad U1 class was a series of 120 2-8-4 Berkshires built by the Lima Locomotive Works from 1943 to 1944 for freight service. They were based on the Berkshires used by the Nickel Plate Road, Pere Marquette and Chesapeake & Ohio, and is mechanically identical to those engines, though with some prr cosmetic features. It could achieve 75 mph, and produced around 65,000 lbs of tractive effort. The U1 was equipped with roller bearings on all axles and drive rods for ease of maintenance and smoother running. The class was withdrawn from service by 1957, but 4 have survived, one of which, 7402, is in operation, and was taken by Smudge after his M1 mountain suffered a seized axle box.