The EMD MRS-1 is a type of diesel-electric locomotive built by General Motors Electro-Motive Division for the United States Army Transportation Corps (USATC) in 1952.

Declared un-needed for wartime operations in about 1970, they were then used on various military bases around the United States, with some serving on the Alaska Railroad.

The initial fate of most of the MRS-1 locomotives was to be placed in storage at the USATC's Transportation Materiel Command facility at Marietta, Pennsylvania[5] awaiting a war to use them in; they had not been purchased for peacetime use.

These brand-new locomotives, with at most a couple of weeks' actual use, sat preserved until approximately 1970, when the Pentagon concluded that their plans for a future, large-scale land war no longer included the capture and use of the enemy's railway system.

In May 1953, the locomotive returned to the BRC's shops in Chicago where it was stripped down and examined for abnormal wear from the cold weather, which was not found.

In 1969 it was reactivated and sent to the Vandenberg Air Force Base for service hauling supplies for the proposed Manned Orbiting Laboratory and components for Titan launch vehicles.

Locomotive #1818 was fitted with European buffers and couplers very soon after delivery and sent to Europe for Army testing and training and secondarily as an EMD demonstrator.

The frame side sills are also different; the Alco's are straight from front to rear, while the EMD's step down towards each end of the locomotive.