The ALCO Century 855 was a model of diesel-electric locomotive built in 1964 by the American Locomotive Company for the Union Pacific. The locomotive was notable for being ALCO's most powerful diesel-electric locomotive and, at the time, the most powerful diesel locomotive ever built, being surpassed by the EMD DDA40X in April 1969.
The Century 855 was designed and built specifically for Union Pacific, which was in need of very high horsepower locomotives for its Overland Route through the Rocky Mountains. Despite its impressive power output, all three examples of the class were scrapped by early 1972 due to mechanical unreliability.
History
Powered by a pair of 16 cylinder ALCO 251C diesel engines, and rated at , it was ALCO's answer to the EMD DD35A and the GE U50. The C855 rode on four two-axle trucks, grouped in pairs linked by span bolsters, giving a wheel arrangement of B+B-B+B. The trucks and bolsters were similar to those under UP's earlier turbine locomotives. Only two A units and one B unit were built, all for the Union Pacific, which had also requested double-engined locomotives from EMD and GE in order to replace the turbines, which had become uneconomical to operate.
See also
- List of ALCO diesel locomotives
- ALCO DH643