EMD GP18

The EMD GP18 was a road switcher diesel-electric locomotive produced by General Motors' Electro-Motive Division between December 1959 and November 1963. It entered production as a replacement for the GP9 in EMD's catalog, representing a modest but deliberate step forward in the company's general-purpose locomotive line. The new model designation was chosen to reflect the unit's horsepower rating, a naming convention EMD adopted to help customers quickly identify the power output of a given model. A total of 350 GP18 units were delivered to American railroads during the production run, making it a reasonably successful if not overwhelmingly popular offering. EMD also built examples for export markets during this period, with units going to Mexican railroads, a Brazilian railroad, and smaller quantities delivered to Peru and Saudi Arabia. Among the notable domestic buyers was the Grand Trunk Western, which ordered its units equipped with optional steam generators for passenger train service, a feature that spoke to the locomotive's flexibility as a general-purpose design. The GP18 occupied a relatively brief window in the broader story of first-generation diesel development, arriving after the highly successful GP9 had already saturated much of the domestic market. Its legacy is modest compared to its more numerous predecessors, though it served faithfully on branch lines and secondary assignments for many of its buyer railroads well into the diesel era.

The GP18 was powered by EMD's 16-cylinder 567D1 prime mover, which produced 1,800 horsepower and drove the locomotive through a DC traction system distributed across a four-axle B-B wheel arrangement. The 567D1 represented a refined variant of the long-running 567 engine family that had underpinned EMD's diesel locomotive production since the 1940s. The extra 50 horsepower over the GP9 was relatively modest, but it was sufficient justification for the new model designation and gave the locomotive a slight edge in tractive capability for customers seeking a bit more performance on demanding grades. In outward appearance the GP18 closely followed the established GP7 and GP9 configuration, retaining the familiar carbody proportions that had become standard for EMD road switchers. One distinguishing visual detail was the use of a metal grid covering the radiator shutters, in contrast to the finer mesh arrangement seen on earlier models. Buyers had a degree of flexibility in how their units were configured, with options available for high or low short hoods and the inclusion or exclusion of dynamic brakes depending on the operational requirements of the purchasing railroad.

Models by: Athearn