Railroad Archives Online
- CollectionD0036 - George Werkema Collection
- Series004 - Northern Pacific Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2003 - Railroads--Buildings and Structures
- Subseries Level 3002 - Depots/Freighthouses
- ItemWerkema421 - Northern Pacific depot at Billings, Montana, in 1990.
- ItemWerkema422 - Northern Pacific depot at Bozeman, Montana, in 1993.
- ItemWerkema423 - Northern Pacific depot at Bozeman, Montana, in 1993.
- ItemWerkema424 - Northern Pacific freight depot at Bozeman, Montana, in 1993.
- ItemWerkema425 - Northern Pacific Depot in Centralia, Washington in 1988.
- ItemWerkema426 - Northern Pacific Depot in Centralia, Washington in 1988.
- ItemWerkema427 - Northern Pacific Depot in Centralia, Washington in 1988.
- ItemWerkema428 - Northern Pacific Depot in Centralia, Washington in 1988.
- 68 more...