Northern Pacific steam locomotive 5120 at Pasco, Washington, on August 07, 1937. Number 5120, a class Z-6 built by Alco-Schenectady in 1937, is parked next to the coal dock ramp at Pasco. Photo by Herman Hunt, J.M. Fredrickson collection. Other Subject Classes: steam locomotive, coal dock

Northern Pacific 5120, a Z-6, leads a westbound extra freight up Bozeman Pass near Muir, Montana, in May 1954. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive, freight train.

Northern Pacific steam locomotive 5120 at Logan, Montana, circa 1950. Number 5120, a class Z-6 built by Alco-Schenectady in 1937, is making a light move. Photo by Blackie Moser, J.M. Fredrickson collection. Other Subject Classes: steam locomotive, railroad crew

Northern Pacific 5120, a Z-6, leads a westbound extra freight up Bozeman Pass west of Livingston, Montana, in May 1954. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive, freight train.

Northern Pacific 5120, a Z-6, leads a westbound extra freight up Bozeman Pass west of Livingston, Montana, in May 1954. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive, freight train.

Northern Pacific steam locomotive 5120 at Garrison, Montana, on May 24, 1952. Number 5120 is a class Z-6 built by Alco-Schenectady in 1937. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive in roster photo

Northern Pacific 5120 and 5100, both class Z-6 steam locomotives, wait at Garrison, Montana for their next assignment to help trains over Mullan Pass on May 24, 1952. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive, helper locomotive, telegraph station.

Northern Pacific steam locomotive 5120 at Easton, Washington, in April 1944. Number 5120, a class Z-6 built by Alco-Schenectady in 1937, waits for its next eastbound train at Easton. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive, roster photo

Northern Pacific 5119, a class Z-6, leads a westbound extra freight with stock cars on the head end through downtown Spokane, Washington, in 1953. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive, freight train, stock car.

Northern Pacific steam locomotive 5119 at Spokane, Washington, on May 20, 1953. Number 5119 is a class Z-6 built by Alco-Schenectady in 1937. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive in roster photo