Railroad Archives Online
- CollectionD0288 - Terence Wahl Collection
- Series004 - Northern Pacific Railroad Company
- Subseries Level 1014 - Photographs
- Subseries Level 2001 - Railroads--Equipment and Supplies
- Subseries Level 3002 - Diesel Locomotives
- 21 more...
- ItemTRWahl0721 - Northern Pacific Diesel Locomotive 247, Bellingham, Washington, undated
- ItemTRWahl0722 - Northern Pacific Diesel Locomotive 247, Bellingham, Washington, undated
- ItemTRWahl0831 - Northern Pacific Diesel Locomotive 557, Larson, Washington, undated
- ItemTRWahl0833 - Northern Pacific Diesel Locomotive 557, Bellingham, Washington, undated
- ItemTRWahl0834 - Northern Pacific Diesel Locomotive 557, Bellingham, Washington, undated
- ItemTRWahl0835 - Northern Pacific Diesel Locomotive 557, Bellingham, Washington, undated
- ItemTRWahl0839 - Northern Pacific Diesel Locomotive 557, Bellingham, Washington, undated
- ItemTRWahl0840 - Northern Pacific Diesel Locomotive 557, Bellingham, Washington, undated