Great Northern (US) class Y-1

In the twenties, the Great northern built the new Cascade Tunnel and electrified the complete 73 mile (117 km) section over Stevens Pass with 11,000 V one-phase AC. Previously, only the old tunnel itself was electrified at 6,600 V three-phase AC and they now needed a replacement for the old GE boxcab electrics. So they ordered six 1-C+C-1 boxcabs from ALCO, which got their electric part from General Electric. They were numbered 5010 to 5017 and became class Y-1.

The alternate current from the overhead line was changed to direct current by a motor-generator. Over one hour, the locomotives delivered 3,300 hp, with a continuous output of 3,000 hp. In World War II, 5011 was badly damaged in an accident and its remains were used for a total rebuild where it got the streamlined cabs from the EMD FT.

In 1956, the Cascade Tunnel was dieselized and equipped with large fans to carry away the exhaust fumes. Since the frame of 5011 had been bent in the accident, it had several problems in service and was scrapped. All catenary was removed and the remaining locomotives were sold to the PRR, which called them FF1. The PRR scrapped three of them in the following years, but the last four were used until 1966.