Railroad Archives Online
- CollectionE0483 - Great Northern Railway Historical Society Standard Signal Plans Collection
- Series003 - Great Northern Railway Company (U.S.)
- Subseries Level 1009 - Engineering Records
- Subseries Level 2008 - Physical plant drawing
- Subseries Level 3005 - Signals
- 55 more...
- Item167-67 - Great Northern Railway Standard Signal Plans; Signal, Swift Train Order, 1918
- Item167-68 - Great Northern Railway Standard Signal Plans; Base for 6 Inch Ground Signal Mast, 1918
- Item167-68A - Great Northern Railway Standard Signal Plans; Base for 4 Inch and 5 Inch Ground Signal Mast, 1924
- Item167-68B - Great Northern Railway Standard Signal Plans; Base for 4 Inch and 5 Inch Case Signal Mast, 1924
- Item167-69 - Great Northern Railway Standard Signal Plans; Bearing, Mechanical Semaphore, 1918
- Item167-70 - Great Northern Railway Standard Signal Plans; Cover, Pipe 5 Inch for Train Order Signal, Pinnacle, Signal Mast, 1918
- Item167-71 - Great Northern Railway Standard Signal Plans; Crank Stand, One Way, Horizontal, 1919
- Item167-72 - Great Northern Railway Standard Signal Plans; Pipe Filler, for 4 Inch Pipe Semaphore Bearing, 1918
- Item167-73A - Great Northern Railway Standard Signal Plans; Clamp and Guide for Vertical Connection on Signals, 1918
- 64 more...