Northern Pacific signal equipment, Union Station, Tacoma, Washington, December 11, 1967. Workers installing new Centralized Traffic Control panel in dispatchers office. Photo by J.M. Fredrickson . Other Subject Classes: signal equipment, railroad employee, dispatchers office

Northern Pacific signal bridge at Martin, Washington, circa 1960. Signal bridge with three signal masts, mainline, east portal of Stampede Tunnel in snow. Photo by J.M. Fredrickson . Other Subject Classes: signal equipment, track, tunnel, mountains

Northern Pacific semaphore signal display at Chehalis, Washington, on April 8, 1988. This structure is in the 3rd subdivision of the Tacoma division. Photo by GJ Werkema. Other subject classes: Signal, Semaphore

Northern Pacific semaphore display at the Northwest Railway Museum in Snoqualmie, Washington, on July 20, 2005. Photo by GJ Werkema. Other subject classes: Signal, Semaphore.

Northern Pacific dispatchers office in Union Station at Tacoma, Washington, on January 8, 1968. "Mountain desk" with trainsheet, communications equipment including selective telephone to contact stations. Photo by J.M. Fredrickson . Other Subject Classes: dispatchers office, communications equipment

Northern Pacific dispatchers office in CTC room, Union Station, Tacoma, Washington, on January 14, 1968. "Mountain desk" with trainsheet, communications equipment including direct station telephone. Photo by J.M. Fredrickson . Other Subject Classes: dispatchers office, communications equipment

Northern Pacific dispatchers office in CTC room, Union Station, Tacoma, Washington, on January 14, 1968. "Mountain desk" with trainsheet, communications equipment including direct station telephone. Photo by J.M. Fredrickson . Other Subject Classes: dispatchers office, communications equipment

Northern Pacific dispatchers office in Union Station at Tacoma, Washington, on January 8, 1968. "Mountain desk" with trainsheet, communications equipment including direct station telephone. Photo by J.M. Fredrickson . Other Subject Classes: dispatchers office, communications equipment

Northern Pacific dispatchers office in Union Station at Tacoma, Washington, on January 8, 1968. "Double Track North desk" with trainsheet, communications equipment including direct station telephone. Photo by J.M. Fredrickson . Other Subject Classes: dispatchers office, communications equipment

Northern Pacific dispatchers office in Union Station at Tacoma, Washington, in August 1966, before remodel, with telephone and telegraph equipment. Photo by J.M. Fredrickson . Other Subject Classes: dispatchers office, telegraph, communications equipment