ALCO PA

ALCO PA and PB

Two former Santa Fe PA1s haul railfan passengers on the Delaware & Hudson in October 1974.

Type and origin Power type Diesel-electric Builder Partnership of American Locomotive Company (ALCO) and General Electric (GE) Model PA, PB Build date June 1946 –December 1953 Total produced 297

Specifications AAR wheel arr. A1A-A1A Gauge 4 ft 8 1⁄2 in (1,435 mm) standard gauge 1,600 mm (5 ft 3 in), Brazil Length 65 ft 8 in (20.02 m) Loco weight 306,000 lb (138,799 kg; 139 t) Prime mover ALCO 244 V16 Engine type V16 Four-stroke diesel Aspiration Turbocharger Displacement 10,688 cu in (175.14 l) Generator DC Traction motors 4x GE 746 or 752 DC traction motors Cylinders 16 Cylinder size 9 in × 10 1⁄2 in (229 mm × 267 mm) Transmission Diesel-electric Loco brake Independent air. Optional: Dynamic Train brakes Air

Performance figures Maximum speed 117 mph (188 km/h) Power output 2,000 hp (1,490 kW) — PA-1/PB-1 2,250 hp (1,680 kW) — PA-2/PB-2 Tractive effort 51,000 lbf (226.86 kN)

Career Locale North America, Brazil Disposition Three preserved, two under restoration, one converted to steam generator car, rest scrapped.

ALCO PA refers to a family of A1A-A1A diesel locomotives built to haul passenger trains that were built in Schenectady, New York, in the United States by a partnership of the American Locomotive Company (ALCO) and General Electric (GE) between June, 1946 and December, 1953. They were of a cab unit design, and both cab-equipped lead A unit PA and cabless booster B unit PB models were built.

The PAs, as well as their cousins, the ALCO FAs, were born as a result of Alco's development of a new diesel engine design, the Model 244. In early 1944, development started on the new design, and by November 1945, the first engines were beginning to undergo tests. This unusually short testing sequence was brought about by the decision of Alco's senior management that the engine and an associated line of road locomotives had to be introduced no later than the end of 1946. In preparation for this deadline, by January 1946, the first 16-cylinder 244 engines were being tested, and while a strike delayed work on the locomotives, the first two PA units were released for road tests in June 1946, for testing for one month on the Lehigh Valley Railroad. After these first tests were completed, the locomotives returned to the factory for refurbishment and engine replacement. In September 1946, the first production units, an A-B-A set of PA1s in Santa Fe colors, were released from the factory, and sent to New York's Waldorf-Astoria Hotel, which had a private railroad siding, for exhibition before being launched into road service.

Two models were offered: the 2,000 horsepower (1,500 kW) PA-1/PB-1 (built between September, 1946 and June, 1950); the 2,250 horsepower (1,680 kW) PA-2/PB-2 (built between April, 1950 and December, 1953)