SP&S 4-6-6-4 steam locomotive Number 903, Class Z-6, leaving Pasco, Washington with Train Number 275, March 21, 1939. This locomotive would later become Great Northern Number 4000. Photo by Al Farrow.

SP&S 4-6-6-4 steam locomotive Number 903, Class Z-6, with a freight train at Camas, Washington, undated. Photo by Jerry Franklin.

SP&S 4-6-6-4 steam locomotive Number 903, Class Z-6, with a westbound freight, undated. Photo by Emery J. Roberts.

SP&S 4-6-6-4 steam locomotive Number 903, Class Z-6, and an American Locomotive Company (ALCO) FB diesel power at the east end of the Wishram, Washington enginehouse, undated.

SP&S 4-6-6-4 steam locomotive Number 904, Class Z-6, with a freight train at Camas, Washington, undated.

SP&S 4-6-6-4 steam locomotive Number 905, Class Z-6, arriving with a freight train at Pasco, Washington on June 1, 1941.

SP&S 4-6-6-4 steam locomotive Number 905, Class Z-6, backing to a train at Wishram, Washington on October 9, 1951. Photo by John Labbe.

SP&S 4-6-6-4 steam locomotive Number 905, Class Z-6, on the west end of the Wishram engine house track, October 9, 1951. Photo by John Labbe.

A view of SP&S 4-6-6-4 steam locomotive Number 910, Class Z-8, with the Scribner Turn at Scribner Junction, Washington and SP&S an American Locomotive Company (ALCO) RS-3 Number 65, circa 1952. Photo by Gene Harsch.

SP&S 4-6-6-4 steam locomotive Number 910, Class Z-8, with the Scribner Turn, waiting for signal at Scribner Junction, Washington, circa 1952. Photo by Gene Harsch.