The ALCO PB1 2000Hp. built from 1946 to 1949, gear ratio gave speeds of 80mph, 90mph, 100mph, and 117mph. used for passenger trains, later freight. The engine had an exhaust-actuated turbocharger so that until the engine revved up to speed there was a lack of oxygen causing improper combustion and a lot of black smoke.
This is D&RGW .In 1947 D&RGW got 2 PB1s, note B units had no numbers on the side.