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
- 6039 more...
- ItemBB025698 - Northern Pacific Engineering Drawing: Details of Bents 1/2, Bridge 52 (54), West of Spire Rock, Montana, undated
- ItemBB025699 - Northern Pacific Engineering Drawing: Detail of Bents 3/4, Bridge 52 (54), West of Spire Rock, Montana, undated
- ItemBB025700 - Northern Pacific Engineering Drawing: Detail of Bent 5, Bridge 52 (54), West of Spire Rock, Montana, undated
- ItemBB025701 - Northern Pacific Engineering Drawing: Detail of Bent 6, Bridge 52 (54), West of Spire Rock, Montana, undated
- ItemBB025702 - Northern Pacific Engineering Drawing: Detail of Bent 6, Bridge 52 (54), West of Spire Rock, Montana, undated
- ItemBB025703 - Northern Pacific Engineering Drawing: Detail of Bent 7, Bridge 52 (54), West of Spire Rock, Montana, undated
- ItemBB025704 - Northern Pacific Engineering Drawing: Detail of Bent 8, Bridge 52 (54), West of Spire Rock, Montana, undated
- ItemBB025705 - Northern Pacific Engineering Drawing: Detail of Bents 9, Bridge 52 (54), West of Spire Rock, Montana, undated
- ItemBB025706 - Northern Pacific Engineering Drawing: Detail of Longitudinal Brace, Bridge 52 (54), West of Spire Rock, Montana, undated
- 1680 more...