SP&S 4-6-6-4 steam locomotive Number 901, Class Z-6, with an eastbound freight departing Pasco, Washington on May 9, 1938. Photo by Al Farrow.

SP&S 4-6-6-4 steam locomotive Number 901, Class Z-6, departing with a freight train from Pasco, Washington on May 9, 1938.

SP&S 4-6-6-4 steam locomotive Number 902, Class Z-6, westbound in a meet with a passenger local near Cliffs, Washington, May 5, 1947. From the Phillip C. Johnson Collection.

SP&S 4-6-6-4 steam locomotive Number 902, Class Z-6, with a string of stock cars at the Kennewick, Washington depot, September 2, 1954.

SP&S 4-6-6-4 steam locomotive Number 902, Class Z-6, with a string of stock cars at the Kennewick, Washington depot, September 2, 1954.

SP&S 4-6-6-4 steam locomotive Number 902, Class Z-6, with the Scribner Turn at the junction near Marshall, Washington on May 17, 1953. Photo by Ron V. Nixon.

SP&S 4-6-6-4 steam locomotive Number 902, Class Z-6, with the Scribner Turn at Marshall, Washington on May 17, 1953. Photo by Ron V. Nixon.

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.