Diesel of the Day 7/25: GE U25B

For July 25th, the Diesel of the Day is the General Electric U25B, nicknamed the U-Boat. This model was GE’s very first entry into the higher horsepower road locomotive market, first built in 1959, with 478 built through 1966. This unit was revolutionary in several ways, including having an engine compartment with positive ventilation. The U25B was the first in a very long line of GE locomotives to be powered by the venerable 7FDL engine, used in every GE road locomotive up to the AC4400CW and Amtrak P42DC. The version in the U25B is a V16 that produces 2,500 horsepower. It was also the highest horsepower diesel in the world when it was introduced, with the contemporary EMD GP20 making 2,000 HP and Alco RS27 2,400 HP. The U25B put serious pressure on Alco, to the point of eventual financial ruin, and set into effect a series of events that would eventually topple EMD as the locomotive sales leader. The U25B was a powerful puller, but very few still exist today…a classic case of nobody thinking to preserve something until it’s mostly gone. The photo shows one of only two operational examples surviving today, Southern Pacific number 3100. You can see the trademark one-piece windshield, giving rise to their other nickname of ‘Cylons’.