Railroad Archives Online
- CollectionD0027 - Timothy Miller Collection
- Series004 - Northern Pacific Railroad Company
- Subseries Level 1009 - Engineering Records
- Subseries Level 2008 - Physical plant drawing
- Subseries Level 3003 - Maintenance Facilities
- 831 more...
- ItemStruc006967 - Northern Pacific Engineering Drawing, Unnamed Structure at Helena, Montana, 1969
- ItemStruc006968 - Northern Pacific Engineering Drawing, Unnamed Structure at Helena, Montana, 1956
- ItemStruc006969 - Northern Pacific Engineering Drawing, Unnamed Structure at Helena, Montana, 1969
- ItemStruc006970 - Northern Pacific Engineering Drawing, Unnamed Structure at Helena, Montana, 1964
- ItemStruc006971 - Northern Pacific Engineering Drawing, Unnamed Structure at Helena, Montana, 1960
- ItemStruc006973 - Northern Pacific Engineering Drawing, Unnamed Structure at Helena, Montana, 1950
- ItemStruc006974 - Northern Pacific Engineering Drawing, Unnamed Structure at Helena, Montana, undated
- ItemStruc006975 - Northern Pacific Engineering Drawing, Unnamed Structure at Helena, Montana, 1950
- ItemStruc006976 - Northern Pacific Engineering Drawing, Unnamed Structure at Helena, Montana, 1950
- 471 more...