ALCO DH-643

The DH -643, also of Century 643H ALCO was a diesel-hydraulic locomotive. They were the first manufactured in the United States -haul locomotives with such a drive.

History

As part of the testing of diesel-hydraulic locomotives, the Southern Pacific Railroad ordered from ALCO three locomotives to a possibility of comparison to the ML 4000 CC to have delivered from Germany by Krauss -Maffei. ALCO saw the opportunity to offer an American alternative to the import locomotives and with the development of the DH -643 to maintain a technological edge over any fellow competitors. Particularly, it should be determined whether the slow-running American diesel engines were suitable for the diesel-hydraulic drive and whether a reduction of maintenance costs was possible at the same time.

ALCO locomotives delivered in September 1964. As the locomotives of Krauss-Maffei showed the vehicles themselves efficient in pest -prone and less especially when used on the routes in the rugged mountainous regions. Thus then was the regular service on the flat routes in the San Joaquin Valley in California.

Due to the frequent technical problems and increased maintenance costs due to the hydraulic force transmission the locomotives were retired in 1970 and scrapped in 1973.

Design features

The locomotives had two four-stroke V-12 diesel engines in the ALCO 251C series with a total of 3165 kW. As power transmission were made ​​by Voith gearbox. Otherwise, the locomotives were largely identical to the diesel-electric locomotives of the Century series.