Northern Pacific steam locomotive 20 at Billings, Montana, on August 19, 1949. Number 20, a class Y-1 built by Schenectady in 1900, is parked in the freight yard. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive, freight yard

Northern Pacific steam locomotive 20 at Billings, Montana, on August 19, 1949. Number 20, a class Y-1 built by Schenectady in 1900, is traveling over a switch in the yard. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive, freight yard

Northern Pacific steam locomotive 2 in 1916. Number 2 was a class M built by Baldwin in 1886 for service on the Stampede Pass switchbacks. Photo by Charles R. Iles, J.M. Fredrickson collection. Other Subject Classes: steam locomotive, roster photo

Northern Pacific steam locomotive 2 at Tacoma, Washington, circa 1922. Number 2 was a class M built by Baldwin in 1886 for service on the Stampede Pass switchbacks. J.M. Fredrickson collection. Other Subject Classes: steam locomotive, roster photo

Northern Pacific steam locomotive 1919 with a freight train at Glendive, Montana, circa 1950. Number 1919 is a class W-2 built by Alco-Brooks in 1904. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive in roster photo

Northern Pacific steam locomotive 1917 as a compound at Pasco, Washington, circa 1910. Number 1917 is a class W-2 built by Alco-Brooks in 1904. J.M. Fredrickson collection. Other Subject Classes: steam locomotive in roster photo

Northern Pacific steam locomotive 1917 in the deadline at Mandan in North Dakota, circa 1957. Number 1917 is a class W-2 built by Alco-Brooks in 1904. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive in roster photo

Northern Pacific steam locomotive 1917 with an extra water tender at Glendive, Montana, circa 1950. Number 1917 is a class W-2 built by Alco-Brooks in 1904. Photo by J.M. Fredrickson. Other Subject Classes: steam locomotive in roster photo

Northern Pacific steam locomotive 1917 at Forsyth, Montana, in January 1935. Number 1917 is a class W-2 built by Alco-Brooks in 1904. Photo by Herman Hunt, J.M. Fredrickson collection. Other Subject Classes: steam locomotive, roster photo

Northern Pacific steam locomotive 1916 at Forsyth, Montana, in January 1935. Number 1916 is a class W-2 built by Alco-Brooks in 1904. Photo by Herman Hunt, J.M. Fredrickson collection. Other Subject Classes: steam locomotive, roster photo