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
- 49 more...
- Item167-59 - Great Northern Railway Standard Signal Plans; Train Order Signal, Two Lever Wall Machine, 1918
- Item167-64A - Great Northern Railway Standard Signal Plans; Crank Stand, One-Way Vertical 12 Inch High, 1917
- Item167-64B - Great Northern Railway Standard Signal Plans; Crank Stand, One-Way Vertical 14-3/4 Inch, 1918
- Item167-65A - Great Northern Railway Standard Signal Plans; Crank Stand, Two-Way Vertical 12 Inch High, 1917
- Item167-65B - Great Northern Railway Standard Signal Plans; Crank Stand, Two-Way Vertical 14-3/4 Inch, 1918
- Item167-66 - Great Northern Railway Standard Signal Plans; Spectacle, Train Order Semaphore, 1917
- 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
- 70 more...