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
- 6760 more...
- 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
- ItemBB028729 - Northern Pacific Engineering Drawing: Detail of Bents 3/5, Bridge 51 (50), West of Spire Rock, Montana, undated
- ItemBB028730 - Northern Pacific Engineering Drawing: Detail of Bents 3/5, Bridge 51 (50), West of Spire Rock, Montana, undated
- ItemBB028731 - Northern Pacific Engineering Drawing: Detail of Bent 4, Bridge 51 (50), West of Spire Rock, Montana, undated
- ItemBB028732 - Northern Pacific Engineering Drawing: Detail of Bent 4, Bridge 51 (50), West of Spire Rock, Montana, undated
- ItemBB028733 - Northern Pacific Engineering Drawing: Detail of Bent 6, Bridge 51 (50), West of Spire Rock, Montana, undated
- ItemBB028734 - Northern Pacific Engineering Drawing: Detail of Bent 7, Bridge 51 (50), West of Spire Rock, Montana, undated
- ItemBB028735 - Northern Pacific Engineering Drawing: Detail of Bent 8, Bridge 51 (50), West of Spire Rock, Montana, undated
- 959 more...