The Great Northern Railway's class Y-1 comprised eight electric locomotives with AAR 1-C+C-1 wheel arrangements.

After being involved in a wreck at Tonga, Washington in July 1945, the 5011 was rebuilt with a streamlined appearance using cabs from an EMD FT[1]; the GN reclassified it as Y-1a.

All Y-1 units were later repainted into the GN Empire Builder scheme (Orange with a black stripe in the middle with yellow pinstriping running along the sides and a black section at the top with yellow pinstriping) and were equipped with busbars located where the headlights and bells used to be to connect the 11kV AC current between units when doing multiple-unit operation.

Crews affectionately gave these apparatuses the nickname "stingers" due to the shape and placement of them.

The electrical system was decommissioned, and the Y-1 locomotives were sold to the Pennsylvania Railroad, who classified them as FF2.