The W-1 was a class of electric locomotive used by the Great Northern Railway.

They were constructed to haul trains on the 73-mile (117 km) electrified portion of the railroad across the Cascade Mountains from Wenatchee, Washington to Skykomish, Washington, including the Cascade Tunnel.

The locomotives were built at General Electric's Erie works in 1947, and were numbered 5018 and 5019.

They were powered by two W-1 motor-generators, with a total 5,000 horsepower (3.7 MW), and at that time were the largest single-unit electric locomotives used in North America.

Unit 5018 was sold to the Union Pacific, who used its body and running gear as part of the unsuccessful experimental coal burning turbine-electric locomotive #80.