The ALCO C-643DH, also known as the Century 643DH, was a twin-engine diesel-hydraulic locomotive, the first diesel-hydraulic road switcher built in the United States. It had a C-C wheel arrangement and generated . Only three were built, all for Southern Pacific Railroad in 1964 (#9018–#9020). The Alco C-643DHs joined 21 Krauss-Maffei ML-4000 diesel-hydraulics already on the Southern Pacific's roster. They spent most of their service lives in the flat San Joaquin Valley in California.
Dissatisfaction over the poor performance of diesel-hydraulic locomotives, as well as their use of foreign-made components (the hydraulic transmission was of German Voith design), eventually led Southern Pacific to sell the three units for scrap in 1973. None were preserved.
Original owners
Railroad Quantity Road numbers NotesSouthern Pacific Railroad 3 9018–9020 renumbered 9150–9152
See also List of ALCO diesel locomotives ALCO Century 855
References
External links Alco Six-Axle Centuries Roster Southern Pacific DH-643