SP&S 4-6-6-4 steam locomotive Number 902, Class Z-6, with a freight train at Hangman Creek, near Spokane, Washingon, undated.

SP&S 4-6-6-4 steam locomotive Number 902, Class Z-6, with an eastbound freight departing Vancouver, Washington, September 23, 1952. John Labbe Photograph.

SP&S 4-6-6-4 steam locomotive Number 902, Class Z-6, leaving Pasco, Washington as Extra 902 West, September 2, 1954. Photo by Al Farrow.

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.