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The P-12-42's eight-cylinder opposed piston engine was rated at 1,600 horsepower (1,200 kW) after 1950, but train lighting and other ancillary loads ("hotel" power) used about 25% of output, leaving 1,200 horsepower (890 kW) for traction. The 100-ton units measured 60 ft 0 in (18.29 m) long by 10 ft 6 in (3.20 m) wide by 12 ft 0 in (3.66 m) high, and were configured in a B-2 wheel arrangement mounted atop a pair of two-axle AAR road trucks, geared for 117 mph (188 km/h) with only the first two axles powered. The P-12-42 was one of the first locomotives to have its prime mover configured to run at a constant speed, with traction generator output regulated solely by excitation.
F-M expected to sell many more units to the New Haven, and to spin the technological advance off into a line of passenger units, including a proposal that used a Train Master-style carbody, but with financial troubles preventing F-M from extending financing to customers, the cash-strapped New Haven ultimately opted to purchase a fleet of sixty EMD FL9s instead, as GM financing was available for the purchase.
The New Haven's Talgo train was sold to Ferrocarril de Langreo for service in Spain, in 1962, and their locomotives sat unused afterwards, until being scrapped in 1971. The Boston and Maine's train remained in service until 1964.
See also
The Roger Williams, a lightweight, high speed DMU train, built for the New Haven.
Sweetland, David R. (1996). C-Liners: Fairbanks-Morse's Consolidation Line of Locomotives. Withers Publishing, Halifax, PA. ISBN1-881411-10-9. — also covers the P-12-42.