The GE U28Bdiesel-electric locomotive model replaced the U25B in early 1966, featuring a slightly uprated prime mover (only 300 hp (220 kW) more power than the U25B). Early units had the same carbody styling as the U25B, while later units had design features (e.g., shortened nose) more in common with later models. After only a year of production, this model was superseded by the U30B.
Trains Magazine editor David P. Morgan wrote about General Electric's decision to go with 2800 horsepower in its 1966 locomotive production. The short article Morgan wrote in the November 1965 issue had line drawings of the proposed short nose U28B.