Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number PD-15730, Reference Number 10102, Sheet 001.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number PD-18050, Reference Number 10102, Sheet 001.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number PD-18050, Reference Number 10102, Sheet 003.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number PD-18050, Reference Number 10102, Sheet 005.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number PD-15728, Reference Number 10102.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number PD-15729, Reference Number 10102, Sheet 003.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number PD-15733, Reference Number 10105, Sheet 003.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number PD-15733, Reference Number 10105, Sheet 011.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number PD-15733, Reference Number 10105, Sheet 013.

Great Northern Engineering Drawing: Flathead Tunnel, Montana, prepared in 1971. Burlington Northern File Number 973D736, Reference Number 10102, Sheet 002.