Railroad Archives Online
- ФондовиD0288 - Terence Wahl Collection
- Серија004 - Northern Pacific Railroad Company
- Подсерија014 - Photographs
- 001 - Railroads--Equipment and Supplies
- 002 - Diesel Locomotives
- ЈединицаTRWahl0005 - Northern Pacific Diesel Locomotive 6511, Seattle, Washington, October 1951
- ЈединицаTRWahl0006 - Northern Pacific Diesel Locomotive 409, Seattle, Washington, October 1951
- ЈединицаTRWahl0169 - Northern Pacific Diesel Locomotive, Bellingham, Washington, undated
- ЈединицаTRWahl0251 - Northern Pacific Diesel Locomotive 247, Bellingham, Washington, undated
- ЈединицаTRWahl0262 - Northern Pacific Diesel Locomotive 215, Arlington, Washington, undated
- 24 више...