Railroad Archives Online
- CollectionD0036 - George Werkema Collection
- Series004 - Northern Pacific Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2004 - Railroad Tracks
- Subseries Level 3001 - Mainline Photos
- ItemWerkema625 - Northern Pacific rail remaining in the alley at Bellingham, Washington, in 2001.
- ItemWerkema626 - Northern Pacific rail remaining in the alley at Bellingham, Washington, in 2001.
- ItemWerkema627 - Northern Pacific rail remaining in the alley at Bellingham, Washington, in 2001.
- ItemWerkema630 - Burlington Northern switchstand at Easton, Washington, in 1887.
- ItemWerkema631 - Northern Pacific wye track switch at Easton, Washington, in 1987.
- ItemWerkema632 - Northern Pacific wye track switch at Easton, Washington, in 1987.
- ItemWerkema634 - Spokane, Portland & Seattle Junction in Kennewick, Washington, in 1981.
- ItemWerkema636 - Northern Pacific's abandoned Marion Branch track at Hastings, North Dakota in 2003.
- ItemWerkema637 - Lake Whatcom Railway end of track near Park, Washington, in 2008.