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 3006 - Cabooses (Railroads)
- ItemTRWahl0009 - Northern Pacific Caboose 1276, Kelso, Washington, August 1951
- ItemTRWahl0265 - Northern Pacific Caboose 1239, Arlington, Washington, undated
- ItemTRWahl0485 - Northern Pacific Caboose 1294, Bellingham, Washington, undated
- ItemTRWahl0832 - Northern Pacific Caboose, Bellingham, Washington, undated