EMD GP49

The EMD GP49 was a four-axle diesel-electric road switcher produced by General Motors' Electro-Motive Division between 1983 and 1985. It was positioned within EMD's so-called 50 series, a family of locomotives introduced around 1979 that also included the GP50, SD50, and the SD49, which was advertised but never actually manufactured. Of the entire 50 series lineup, the GP49 was built in the smallest numbers by a considerable margin, with only 41 units constructed across its brief production run, compared to hundreds of GP50s and SD50s delivered to railroads across North America. The Alaska Railroad was the primary customer for the true GP49 model, placing two separate orders for a total of nine units. The first batch, numbered 2801 through 2804, was delivered in September 1983, while a second order comprising units 2805 through 2809 followed in May 1985. The remaining 32 units of the total production figure came from a separate but related lineage: six GP39X locomotives had originally been constructed in November 1980 for the Southern Railway, and these were subsequently upgraded to GP49 specification, with the resulting machines later finding service with Tri-Rail in Florida following remanufacturing by Mid-America Car Company for commuter passenger duties, where they were redesignated GP49H-3. Over the decades following their original service with the Alaska Railroad, the GP49 fleet was dispersed among several operators. In December 2006, the Alaska Railroad auctioned five units to Helm Leasing for approximately 1.3 million dollars. Subsequent years saw individual units acquired by short line operators in the American West and freight railways in Chile, including Ferronor, which modified two units into six-axle configurations for iron ore service between Los Colorados Mine and the port at Huasco, and TRANSAP, which refitted two others with A1A bogies to reduce axle loading on lighter trackage.

The GP49 was powered by an EMD 12-cylinder 645F3B prime mover, which produced a gross output of approximately 2,950 horsepower, with 2,800 horsepower available for traction and the remaining 150 horsepower allocated to onboard auxiliary systems. The locomotive rode on a B-B wheel arrangement, meaning two two-axle trucks, and employed direct current traction through four D87 traction motors fed by an AR15 main alternator rated at 4,680 amperes. One distinctive operational feature was the inclusion of EMD's Super Series wheel slip control system, originally introduced on the experimental GP40X, which used a radar unit mounted beneath the front pilot to measure actual ground speed and allow the locomotive's control systems to modulate motor speed and prevent wheel slip, a capability that contributed to the GP49's characteristically deliberate acceleration behavior. Externally, the GP49 bore a close resemblance to the more numerous GP50, and the two could be confused at a distance, but several details distinguished them. The GP49 used two 48-inch radiator fans positioned above the cooling section, whereas the GP50 employed three fans in the same location. The engine room access door arrangement also differed, with the GP49 featuring eight access doors per side beneath the dynamic brake blister, compared to ten on the GP50. These distinctions reflected the GP49's somewhat less complex cooling and engine room layout, consistent with its intermediate position in the 50 series family.

Models by: Athearn