ALCO PA and PB Locomotives

ALCO PA and PB

From Wikipedia, the free encyclopedia

ALCO PA refers to a family of A1A-A1A diesel locomotives built to haul passenger trains that were built in Schenectady, New York in theUnited 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.

ALCO PA and PB
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)
Length	65 ft 8 in (20.02 m)
Locomotive weight	306,000 lb (138.8 t)
Prime mover	ALCO 244 V16
Engine type	Four-stroke diesel
Aspiration	Turbocharger
Displacement	10,688 cu in (175.14 l)
Cylinders	V16
Cylinder size	9 in × 10 1⁄2 in (229 mm × 267 mm)
Transmission	DC generator, DC traction motors
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)
Locomotive brake	Independent air. Optional:Dynamic
Train brakes	Air
Career
Locale	North America, Brazil

Background and development[edit]

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.^[1]

History[edit]

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)

Models popularly termed the PA-3/PB-3 were in fact only an upgrade of the PA-2/PB-2. The true PA-3/PB-3 model would have boasted 2,400 horsepower (1,800 kW), though none were ever built. Aside from the small power increase between the PA-1 and the PA-2, differences were minor. Externally PA-2s could be distinguished by the absence of the "eyebrow" trim piece on the grille behind the cab and the porthole window behind the radiator shutters. Internally, later PA-2 and PB-2 production featured a water-cooled turbocharger and other engine compartment changes, but these were frequently added to older models undergoing major repairs or overhauls. Four PA-1s were upgraded by Morrison-Knudsen in 1974-75 for passenger service on the Delaware & Hudson and became the PA4.^[2] These were eventually used by Amtrak for the "Adirondack" train and then by the Mass Bay Transit Authority before being sold to Mexico.

Fans deemed the PA one of the most beautiful diesels and an "Honorary Steam Locomotive", as noted by Professor George W. Hilton in a book review in September, 1968 Trains Magazine. When accelerating, until the turbocharger came up to speed thick clouds of black smoke would pour from the exhaust stacks, due to turbo lag. Photographing a moving PA while smoking became a prime objective of railfans^[3][4][5]Like its smaller cousin, the ALCO FA, the PA had distinctive styling, with a long, straight flat-tipped nose with a headlight in a square, slitted grille, raked windshields, and trim pieces behind the cab windows that lengthened and sleekened the lines. The overall design owed something to the Fairbanks-MorseErie-built design, which had been constructed by ALCO's electrical equipment partner General Electric at their Erie, Pennsylvania plant. The majority of PA components were compatible with the FA.

The ALCO 244 V16 diesel prime mover proved to be the undoing of the PA: The engine had been rushed into production, and proved to be unreliable. The PA locomotives failed to capture a marketplace dominated by General Motors Electro-Motive Divisionand their E-units. The original Santa Fe three unit set #51L, 51A and 51B was repowered in August 1954 with EMD 16-567C engines rated at 1,750 hp (1,305 kW). This EMD repowering of the PAs was economically unfeasible and the remaining Santa Fe PAs retained their 244 engines. The later 251-series engine, a vastly improved prime mover, was not available in time for ALCO to recover the loss of reputation caused by the unreliability of the 244. By the time the ALCO 251 engine was accepted into widespread use, General Electric (which ended the partnership with ALCO in 1953) had fielded their entries into the diesel-electric locomotive market. General Electric eventually supplanted ALCO as a manufacturer of locomotives. ALCO's loss of market share led to its demise in 1969
.