Great Northern Engineering Drawing: Flathead Tunnel at Twin Meadows, Montana, prepared in 1973. Burlington Northern File Number 9883, Reference Number 10110.

Great Northern Engineering Drawing: Flathead Tunnel at Twin Meadows, Montana, prepared in 1973. Burlington Northern File Number 9883, Reference Number 10110.

Great Northern Engineering Drawing: Flathead Tunnel at Twin Meadows, Montana, prepared in 1973. Burlington Northern File Number 9883-1A, Reference Number 10108.

Great Northern Engineering Drawing: Flathead Tunnel at Twin Meadows, Montana, prepared in 1973. Burlington Northern File Number 9883, Reference Number 10110.

Great Northern Engineering Drawing: Flathead Tunnel at Twin Meadows, Montana, prepared in 1973. Burlington Northern File Number 9883, Reference Number 10110.

Great Northern Engineering Drawing: Flathead Tunnel at Twin Meadows, Montana, prepared in 1975. Burlington Northern File Number 9883-2, Reference Number 10107.

Great Northern Engineering Drawing: Flathead Tunnel at Twin Meadows, Montana, prepared in 1977. Burlington Northern File Number 9883-1, Reference Number 10108.

Great Northern Engineering Drawing: Flathead Tunnel at Twin Meadows, Montana, prepared in 1977. Burlington Northern File Number 9883, Reference Number 10110, Sheet 001.