ALCO Century 643DH

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of German Voith design), eventually led to Southern Pacific withdrawing the C-643DHs units, and all three of them were withdrawn and scrapped in 1973.
==Gallery==
* Gallery
Category:Diesel locomotives
Category:ALCO locomotives
Category:Southern Pacific locomotives
Category:American locomotives
Category:Built in 1964
Category:Six-axled diesel locomotives
Category:Scrapped locomotives
Category:C-C locomotives
Category:Road Diesel Locomotives
Category:ALCO Century Series
Category:Scrapped in 1973
Category:ALCO diesel locomotives
Category:Diesel-hydraulic locomotives
Category:Scrapped diesel locomotives