Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number 973D754, Reference Number 10101, Sheet 007.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number 973D737, Reference Number 10101, Sheet 001.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number 973D737, Reference Number 10102, Sheet 003.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number 973D737, Reference Number 10102, Sheet 007.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number 973D737, Reference Number 10101, Sheet 002.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number PD-15731, Reference Number 10102.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1973. Burlington Northern File Number EM7333-4000, Reference Number 10111.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1973. Burlington Northern File Number TWIN MEADOWS,MT., Reference Number 10109.

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

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1973. Burlington Northern File Number TWIN MEADOWS,MT., Reference Number 10112.