Sunday, July 31, 2011

the ALCo alligator


The first loco in the centre of this sea of Santa Fe blue and yellow locomotives at the Summit of Cajon Pass in 1968 -- one of the rare locations in the US where there is left hand running on double track -- is an ALCo RSD-15 which could be ordered with either a high or low short hood; railfans nicknamed the low short hood version "Alligators" because of their unusually long low noses.

The total production between August 1956 and June 1960 was only 75 and of these 50 were bought by Santa Fe. Built at the American Locomotive Company at Schenectady, New York, the RSD-15 was powered by an ALCo 251 16-cylinder four-cycle V-type prime mover rated at 2,400 horsepower (1.79 MW); it superseded the almost identical ALCo 244-engined RSD-7, and was catalogued alongside the similar but smaller 1,800 hp (1.34 MW) RSD-12, powered by a 12-cylinder 251-model V-type diesel engine. The two bogies (trucks) each contained 3 axles powered by General Electric model 752 traction motors. These bogies had an asymmetrical axle spacing due to the positioning of the traction motors. The six-motor design allowed higher tractive effort at lower speeds than an otherwise similar four-motor design.

Five of the 75 locos are preserved today.

More specifications

Length 66 ft 7 in (20.29 metres)

Width 10 ft 1 in (3.07 m)

Height 14 ft 11 in (4.55 m)

Locomotive weight 335,000 lb (152.0 tonnes)

Fuel capacity 3,350 US gallons (12,700 litres; 2,790 imp gal)

Engine type 4-stroke diesel

Generator GE GT586

Top speed 65 mph (105 km/h)

Power output 2,400 hp (1.79 MW)

Tractive effort :

Starting: 95,600 lbf (425.2 kN) at 25% adhesion;

Continuous: 79,500 lbf (353.6 kN) at 12 mph (19 km/h)

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