Two Northern Pacific class W-3 locomotives help a freight train up the South Tacoma Hill on the Prairie Line in Tacoma, Washington, circa 1953. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive, helper locomotive, freight train.

Four helper engines push a train past the depot and water tank at Weston, Washington, circa 1911. J.M. Fredrickson collection. Other Subject Classes: steam locomotive, water tank.

Northern Pacific steam tender used for storing diesel oil at Pasco, Washington, on October 4, 1971. Photo by GJ Werkema Other subject classes: Steam locomotive Tender.

Northern Pacific steam tender used for storing diesel oil at Pasco, Washington, on October 4, 1971. Photo by GJ Werkema Other subject classes: Steam locomotive Tender.

Northern Pacific Terminal 30 prepares to leave with coach es 627 and 634 while Northern Pacific 1070 waits in the engine house on the Lake Whatcom Railway at Wickersham, Washington, on October 18, 2008. Northern Pacific Terminal 30 is an American Locomotive Company model S-1 in 1940. Northern Pacific 1070, a class L-9 0-6-0 switcher, built by American Locomotive Company in 1907. Photo by GJ Werkema. Other subject classes: steam locomotive, switcher locomotive, L-9

Northern Pacific troop train, Passenger Extra 1823 East, at Allentown, Washington, in 1946. Class W-3 Mikado-type steam locomotive number 1823, leads Pullman troop sleepers and standard sleeping cars. Photo by J.M. Fredrickson. Other Subject Classes: troop train, steam locomotive, passenger car

Northern Pacific troop train, Passenger Extra 1823 East, at Allentown, Washington, in 1946. Class W-3 Mikado-type steam locomotive number 1823, leads Pullman troop sleepers and standard sleeping cars. Photo by J.M. Fredrickson. Other Subject Classes: troop train, steam locomotive, passenger car

Northern Pacific troop train, Passenger Extra 2602 West, at Covington, Washington, on August 8, 1950. Class A Northern-type steam locomotive number 2602 leads Pullman sleeping cars and army kitchen car beneath road bridge. Photo by J.M. Fredrickson. Other Subject Classes: passenger train, steam locomotive, passenger car

Northern Pacific troop train, Passenger Extra 2602 West, at Covington, Washington, on August 8, 1950. Class A Northern-type steam locomotive number 2602 leads Pullman sleeping cars and army kitchen car beneath road bridge. Photo by J.M. Fredrickson. Other Subject Classes: passenger train, steam locomotive, passenger car

Northern Pacific troop train, Passenger Extra 2608 West, departs Tacoma, Washington, circa 1950. Class A Northern-type steam locomotive number 2608 leads express box cars and Pullman sleeping cars off the drawbridge line through the Tacoma tideflats. Photo by J.M. Fredrickson. Other Subject Classes: troop train, steam locomotive, freight car, passenger car, railroad yard