ALCO Century 643DH

ALCO Century 643DH
Technical specifications
Manufacturer(s)	American Locomotive Company
Type of locomotive	Diesel-hydraulic
Constructed	September 1964
Number built	3
Classification	DH643
Gauge	4 Foot 8+1⁄2 Inches (1,435 mm)
Prime mover	ALCO 251C, (x 2)
Service information
Fleet numbers	First Numbering: 9018–9020 Later Numbering: 9150–9152 Final Numbering: 9800-9802
Preservation information
Preserved	None of the three were preserved, all three were scrapped

The ALCO C-643DH, also known as the ALCO Century 643DH, was a twin-engine diesel-hydraulic locomotive built by the American Locomotive Company, it was also the first diesel-hydraulic road diesel unit to be built in the United States.

History

Technical Specifications

Regarding technical specifications, the C denoted that it was part of the ALCO Century Line, 6 denoted that it had six axles, the 43 denoted that it could generate and produce 4,300 hp (3,200 kW), and the DH stood for "Diesel-Hydraulic".

Production and Delivery

In-all, only three of these diesel locomotives were ever constructed by ALCO, all three were built for the Southern Pacific Railroad in 1964, they were numbered as 9018–9020. The three ALCO C-643DHs joined 21 Krauss-Maffei ML-4000 diesel-hydraulics that were already on the Southern Pacific's roster. These hydraulic-drive diesels spent most of their service lives in the flat San Joaquin Valley in California.

Performance figures

The top speed the ALCO Century 643DH could do was 77 mph (124 km/h) and their tractive effort was 95,000 lbf (422.58 kN).

Ending

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of German Voith design), eventually led to Southern Pacific withdrawing the C-643DHs units, and all three of them were withdrawn and scrapped in 1973.

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