Piggybacking on Mike's answer, the locomotive was built for USATC service by ALCo under contract for GE. The unit's official designation is E1670 which represents its specification number. The E1670 is often referred to as the ALCo MRS-1 which is technically not correct. The MRS designation - "Military Road Switcher" - was used by EMD to describe its somewhat similar model. In official documentation, even though the units were physically built by ALCo, General Electric is the builder of record.
Initially, 13 units each were built by GE/ALCo and EMD. Following testing, an order was placed with GE for a further 70 units so GE/ALCo production exceeded that of EMD. The locomotives were built with trucks designed to be adjustable for differing track gauges and dimensions of a reduced loading gauge, enabling them to be dispatched worldwide in the event of war. A number of units remain extant and in shortline/tourist train service.
Here's a view of the long hood end of the E1670:
I hope this helps.
Bob
