Railroad Archives Online
- FondsD0027 - Timothy Miller Collection
- Série003 - Great Northern Railway Company (U.S.)
- Sous-série009 - Engineering Records
- 008 - Physical plant drawing
- 008 - Tunnels
- 83 en plus...
- PièceStruc001502 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, 1955
- PièceStruc001503 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, 1956
- PièceStruc001504 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, 1956
- PièceStruc001505 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, 1956
- PièceStruc001506 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, 1956
- PièceStruc001507 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, 1956
- PièceStruc001508 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, 1955
- PièceStruc001509 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, 1956
- PièceStruc001510 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, 1956
- 260 en plus...