Railroad Archives Online
- FondoD0011 - James M. Fredrickson Collection
- Serie004 - Northern Pacific Railroad Company
- Sottoserie014 - Photographs
- 004 - Railroad Tracks
- 002 - Railroad crossings
- Unità documentariaJMF04-02990.0 - Northern Pacific grade crossing at McKenna, Washington, circa 1927.
- Unità documentariaJMF04-03008.0 - Northern Pacific facilities at DuPont, Washington, circa 1927.