The EMD FT is a diesel-electric locomotive that was produced between March 1939 and November 1945, by General Motors' Electro-Motive Corporation (EMC), later known as GM Electro-Motive Division (EMD). The "F" stood for Fourteen Hundred (1400) horsepower (rounded from 1350) and the "T" for Twin, as it came standard in a two-unit set. The design was developed from the TA model built for the C,RI&P in 1937, and was similar in cylinder count, axle count, length, and layout. All told 555 cab-equipped ”A” units were built, along with 541 cabless booster or ”B” units, for a grand total of 1,096 units. The locomotives were all sold to customers in the United States. It was the first model in EMD's very successful F-unit series of cab unit freight diesels and was the locomotive that convinced many U.S. railroads that the diesel-electric freight locomotive was the future. Many rail historians consider the FT one of the most important locomotive models of all time. Design and production The first units produced for a customer were built in December 1940 and January 1941 for the Atchison, Topeka and Santa Fe Railway and numbered the 100 set. These were the first diesel-electric locomotives ever produced with dynamic braking, a system developed at the insistence of the railroad and with its assistance. Initially the four-unit, coupler-equipped set featured two booster units between two cab units in the manner of the demonstrator set. The Brotherhoods of Locomotive Engineers and Firemen, however, insisted that the two cabs required two crews, so the railway had EMD produce extra boosters, and renumbered its earliest sets into four unit sets with one cab unit and three boosters. Negotiation with the unions soon rectified the situation, but as the road's earliest units were geared for higher speeds than subsequent units, these sets continued to be composed of one FTA cab unit and three FTB boosters. This is why the road had ten more FTB booster units than FTA cab units. The original A-B-B-A demonstrator set was sold to the Southern Railway. The FT was equipped with the EMD 567 medium-speed two-stroke cycle Diesel engine, along with its many successors. FTs were generally marketed as semi-permanently coupled A-B sets (a lead unit and a cabless booster connected by a solid drawbar) making a single locomotive of . Many railroads used pairs of these sets back to back to make up a four-unit A-B-B-A