A rare visitor to Denver in 1968, one of UP’s great clattering U50’s dominates the ready tracks at the Pullman roundhouse. Likely the 36 came in early morning off the Julesburg line and will leave after dark the way it came, giving local photographers no chance for action shots. But to contemplate it at rest spectacle enough. These are BIG engines, 83 feet long and over 16 feet tall, with twin 2,500-hp diesels that deliver as much as tractive effort -- 139,000-plus pounds -- as a Big Boy. Union Pacific bought 23 of them -- along with 27 EMD DD35s and three Alco C855s – to replace its turbines. But at half a million pounds engine weight, they were hard on track. When one of the twin diesels broke down the whole unit was out of service. By the mid-1970s, builders were offering 3,000 and more in a single unit, and by 1977, the U50s were gone. Not a single example was preserved.
