Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1968. Burlington Northern File Number TWIN MEADOWS,MT., Reference Number 10110.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1968. Burlington Northern File Number 973D737, Reference Number 10109, Sheet 003.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1969. Burlington Northern File Number PD-15733, Reference Number 10110, Sheet 001.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1970. Burlington Northern File Number PD-15733, Reference Number 10105, Sheet 017.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number PD-15733, Reference Number 10102, Sheet 003.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number PD-15733, Reference Number 10102, Sheet 008.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number PD-15733, Reference Number 10102, Sheet 012.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number PD-15733, Reference Number 10102, Sheet 013.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number PD-15727, Reference Number 10102, Sheet 001.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number PD-15727, Reference Number 10102, Sheet 002.