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 3001 - Bridges
- 6753 more...
- ItemBB028720 - Northern Pacific Engineering Drawing: Falsework, Bridge 51 (50), West of Spire Rock, Montana, undated
- ItemBB028721 - Northern Pacific Engineering Drawing: Proposed West Abutment, Bridge 51 (50), West of Spire Rock, Montana, undated
- ItemBB028722 - Northern Pacific Engineering Drawing: Tie Plan, Bridge 51 (50), West of Spire Rock, Montana, 1962
- ItemBB028723 - Northern Pacific Engineering Drawing: Tie Plan, Bridge 51 (50), West of Spire Rock, Montana, 1962
- ItemBB028724 - Northern Pacific Engineering Drawing: Tie Plan, Bridge 51 (50), West of Spire Rock, Montana, 1962
- ItemBB028725 - Northern Pacific Engineering Drawing: Tie Plan, Bridge 51 (50), West of Spire Rock, Montana, 1962
- ItemBB028726 - Northern Pacific Engineering Drawing: General Plan, Bridge 51 (50), West of Spire Rock, Montana, undated
- ItemBB028727 - Northern Pacific Engineering Drawing: Erection Diagram, Bridge 51 (50), West of Spire Rock, Montana, undated
- ItemBB028728 - Northern Pacific Engineering Drawing: Detail of Bents 1/2, Bridge 51 (50), West of Spire Rock, Montana, undated
- 966 more...