Railroad Archives Online
- CollectionD0027 - Timothy Miller Collection
- Series003 - Great Northern Railway Company (U.S.)
- Subseries Level 1009 - Engineering Records
- Subseries Level 2008 - Physical plant drawing
- Subseries Level 3008 - Tunnels
- 346 more...
- ItemStruc004575 - Great Northern Engineering Drawing, Flathead Tunnel, Montana, 1971
- ItemStruc004576 - Great Northern Engineering Drawing, Flathead Tunnel, Montana, 1971
- ItemStruc004577 - Great Northern Engineering Drawing, Flathead Tunnel, Montana, 1975
- ItemStruc004578 - Great Northern Engineering Drawing, Flathead Tunnel, Montana, 1971
- ItemStruc004579 - Great Northern Engineering Drawing, Flathead Tunnel, Montana, 1971
- ItemStruc008938 - Great Northern Engineering Drawing, Flathead Tunnel, Montana, 1966