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
- 62 more...
- 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
- Item167-73B - Great Northern Railway Standard Signal Plans; Clamp and Guide for Vertical Connection on Signals, 1920
- Item167-75 - Great Northern Railway Standard Signal Plans; Jaws, Solid and Screw, 1918
- Item167-76 - Great Northern Railway Standard Signal Plans; Crank, Right Angle, 1918
- Item167-77 - Great Northern Railway Standard Signal Plans; Adjustable Links, Eye Rods, 1918
- Item167-78 - Great Northern Railway Standard Signal Plans; Wall Cover Plate, for Train Order Signal, 1918
- Item167-80 - Great Northern Railway Standard Signal Plans; Forms for Signal Foundations, 1923
- Item167-80A - Great Northern Railway Standard Signal Plans; Forms for Signal Foundations, 1923
- 57 more...