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
- 91 more...
- Item167-103 - Great Northern Railway Standard Signal Plans; Ladder, Clamps and Stays, Electrical Signals, 1920
- Item167-104 - Great Northern Railway Standard Signal Plans; Ladder Platforms for Electrical Signals, 1920
- Item167-105 - Great Northern Railway Standard Signal Plans; Ladder - Hand Rails, 1919
- Item167-109 - Great Northern Railway Standard Signal Plans; Foundation Signal Ladder, 1920
- Item167-110 - Great Northern Railway Standard Signal Plans; Filler Block, 1920
- Item167-118C - Great Northern Railway Standard Signal Plans; Connector, Track Shunt for Track Walker, 1927
- Item167-121 - Great Northern Railway Standard Signal Plans; Bracket, Cantilever, 1921
- Item167-123 - Great Northern Railway Standard Signal Plans; Signal Seal, 1921
- Item167-124 - Great Northern Railway Standard Signal Plans; Bridge Rail Lock (Special), 1921
- 28 more...