Northern Pacific Engineering Drawing: Roundhouse at Helena, Montana, prepared in 1963. Burlington Northern File Number 4616, Reference Number 10106, Sheet 002.

Northern Pacific Engineering Drawing: Roundhouse at Helena, Montana, prepared in 1961. Burlington Northern File Number 4615, Reference Number 10109, Sheet 5-A.

Northern Pacific Engineering Drawing: Roundhouse at Helena, Montana, prepared in 1960. Burlington Northern File Number 4615, Reference Number 10103, Sheet 005.

Northern Pacific Engineering Drawing: Roundhouse at Helena, Montana, prepared in 1960. Burlington Northern File Number 4615, Reference Number 10103, Sheet 006.

Northern Pacific Engineering Drawing: Roundhouse at Helena, Montana, prepared in 1960. Burlington Northern File Number 4615, Reference Number 10103, Sheet 004.

Northern Pacific Engineering Drawing: Roundhouse at Helena, Montana, prepared in 1960. Burlington Northern File Number 4615, Reference Number 10103, Sheet 003.

Northern Pacific Engineering Drawing: Roundhouse at Helena, Montana, prepared in 1960. Burlington Northern File Number 4615, Reference Number 10103, Sheet 002.

Northern Pacific Engineering Drawing: Roundhouse at Helena, Montana, prepared in 1956. Burlington Northern File Number 4615, Reference Number 10110, Sheet 001.

Northern Pacific Engineering Drawing: Freight House at Helena, Montana, undated. Burlington Northern File Number 4615-4619, Reference Number 101.

Northern Pacific Engineering Drawing: Freight House at Helena, Montana, prepared in 1960. Burlington Northern File Number 4617-5, Reference Number 10103, Sheet 001.