Railroad Archives Online
- FondsD0027 - Timothy Miller Collection
- Série003 - Great Northern Railway Company (U.S.)
- Sous-série009 - Engineering Records
- 008 - Physical plant drawing
- 008 - Tunnels
- 71 en plus...
- PièceStruc001490 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, 1956
- PièceStruc001491 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, 1956
- PièceStruc001492 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, 1956
- PièceStruc001493 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, 1956
- PièceStruc001494 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, undated
- PièceStruc001495 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, 1956
- PièceStruc001496 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, 1956
- PièceStruc001497 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, 1956
- PièceStruc001498 - Great Northern Engineering Drawing, Cascade Tunnel, Washington, 1956
- 272 en plus...