By the early 1960s Union Pacific was looking around for a diesel model to replace its turbines, something that, run in three-unit sets, could produce 15,000 hp. GE’s answer was the twin-engine U50. (EMD and Alco produced their own answers.) First delivered in the fall of 1963, the 5,000-hp U50s pleased the railroad, which went on to order a total of 23, the last delivered less than a year before October 2, 1966, when this picture of the 46 and 53 was made east of North Platte, NE. The 83-foot, 278.5-ton monsters rode on double B-B trucks salvaged from the scrapped 1950-era turbines they replaced and delivered 160,000 pounds starting tractive effort, more even than UP’s Big Boys. They remained on the roster for about a decade.
