EMD GP7u was built in 1951 (builder #15691) for the U.S. Army, #1821.  The Alaska Railroad acquired it in 1976 and numbered it 1810 (later #1821).  It was sold to NIS (#1810) and then to Oregon Pacific Ry (#1810) in 1999.  (Anchorage, 5/13/84)

Retired locomotive engineer Steve Drassler adds, "The 1810 got odd looking square center cab windows during outside rebuild. The other 1800's had more normal looking rectangular center cab windows. I didn't care for the 1810, weak and slow to load."