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 3008 - Tunnels
- ItemStruc004931 - Northern Pacific Engineering Drawing, Subway Under 7th Streetat Olympia, Washington, 1911
- ItemStruc004932 - Northern Pacific Engineering Drawing, Subway Under 7th Streetat Olympia, Washington, 1910
- ItemStruc004933 - Northern Pacific Engineering Drawing, Subway Under 7th Streetat Olympia, Washington, 1911
- ItemStruc004934 - Northern Pacific Engineering Drawing, Subway Under 7th Streetat Olympia, Washington, 1911
- ItemStruc004935 - Northern Pacific Engineering Drawing, Subway Under 7th Streetat Olympia, Washington, 1891
- 124 more...