ALCO DH643

ALCO C-643DH
Southern Pacific #9152, formerly #9020.
Power type Diesel-hydraulic
Builder American Locomotive Company (ALCO)
Order number S-3374
Serial number S-3374-01 – S-3374-03
Model DH-643
Build date September 1964
Total produced 3
AAR wheel arr. C-C
UIC classification C′C′
Gauge 4 feet 8+12 inches (1,435 mm)
Length 75 ft 10 in (23.11 m)
Locomotive weight 378,000 lb (171 t)
Prime mover ALCO 251C, (2)
Engine type Four stroke diesel
Aspiration Turbocharger
Displacement 8,016 cu in (131.36 l)
Cylinders V12, (2)
Cylinder size 9 by 10+12 inches (230 × 270 mm)
Transmission Voith hydraulic
Top speed 77 mph (124 km/h)
Power output 4,300 hp (3,200 kW)
Tractive effort 95,000 lbf (420,000 N)
Locomotive brakes Straight air
Train brakes Air
Career Southern Pacific Railroad
Number 9018–9020 (later 9150–9152; final 9800-9802)
Locale North America
Scrapped 1973

The ALCO C-643DH, also known as the Century 643DH, was a twin-engine diesel-hydraulic locomotive, the first diesel-hydraulic road unit built in the United States. It had a C-C wheel arrangement and generated 4,300 horsepower (3,200 kW). 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. These hydraulic-drive diesels 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 scrap the C-643DHs in 1973.

Original owners

Railroad Quantity Road numbers Notes
Southern Pacific Railroad
3
9018–9020 renumbered 9150–9152

References

External links