SP&S 4-6-6-4 steam locomotive Number 901, Class Z-6, works freight train Number 276 by Pasco, Washington on March 21, 1939.

SP&S 4-6-6-4 steam locomotive Number 901, Class Z-6, at the Northern Pacific servicing facilities at Pasco, Washington on May 9, 1938.

SP&S 4-6-6-4 steam locomotive Number 901, Class Z-6, at the Great Northern yard at Hillyard in Spokane, Washington in July 1947.

SP&S 4-6-6-4 steam locomotive Number 901, Class Z-6, at the Great Northern yard at Hillyard in Spokane, Washington in July 1947.

SP&S 4-6-6-4 steam locomotive Number 901, Class Z-6, at the Great Northern servicing facilities at Hillyard in Spokane, Washington on May 3, 1947.

SP&S 4-6-6-4 steam locomotive Number 901, Class Z-6, at an unknown location and date

The front of the disconnected tender for SP&S 4-6-6-4 steam locomotive Number 901, Class Z-6, at Vancouver, Washington.

SP&S 4-6-6-4 steam locomotive Number 901, Class Z-6, seen taking on water at the Vancouver, Washington servicing facilities.

SP&S 4-6-6-4 steam locomotive Number 901, Class Z-6, seen exiting Tunnel Number 12 east of Wishram, Washington with an eastbound freight. Photo by Jim Mills.

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