Railroad Archives Online
- FondoD0063 - Walter W. Ainsworth Collection
- Serie004 - Northern Pacific Railroad Company
- Subserie014 - Photographs
- 001 - Railroads--Equipment and Supplies
- 006 - Cabooses (Railroads)
- Unidad documental simpleWWANT044 - Northern Pacific freight train at Seattle, Washington, circa 1935.
- Unidad documental simpleWWANT049 - Northern Pacific freight train at Seattle, Washington, circa 1935.
- Unidad documental simpleWWANT079 - Northern Pacific freight train with a wood caboose at Black River, Washington, circa 1941.
- Unidad documental simpleWWANT089 - A Northern Pacific freight train at Black River, Washington, circa 1941.
- Unidad documental simpleWWANT091 - A Northern Pacific freight train at Black River, Washington, circa 1941.
- Unidad documental simpleWWANT093 - A Northern Pacific steam locomotive at Black River, Washington, circa 1941.