Railroad Archives Online
- CollectionD0036 - George Werkema Collection
- Series001 - Burlington Northern Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2004 - Railroad Tracks
- Subseries Level 3002 - Railroad Crossings
- ItemWerkema590 - Burlington Northern crossbucks at Glade, Washington, in 1986.
- ItemWerkema591 - Burlington Northern wigwag crossing signal at Kiona, Washington, in 1986.
- ItemWerkema592 - Burlington Northern flasher and bell crossing signal at Prosser, Washington, in 1986.
- ItemWerkema593 - Burlington Northern wigwag crossing signal in South Tacoma, Washington, in 1993.
- ItemWerkema594 - Burlington Northern wigwag crossing signal in South Tacoma, Washington, in 1993.