Railroad Archives Online
- CollectionD0011 - James M. Fredrickson Collection
- Series010 - Other Railroads
- Subseries Level 1014 - Photographs
- Subseries Level 2004 - Railroad tracks
- Subseries Level 3003 - Railroad yards
- ItemJMF19-14097.0 - Pennsylvania Railroad Interlocking control tower at Pittsburg, Pennsylvania on July 13, 1964.
- ItemJMF19-14250.0 - New Haven Railroad interlocking tower at Old Saybrook, Connecticut on January 28, 1977.
- ItemJMF19-13852.0 - Chicago & North Western Railway control tower at Proviso, Illinois on July 26, 1986.
- ItemJMF19-14221.8 - American Rail Tours rail yard at Pompano Beach, Florida on July 28, 1987.
- ItemJMF19-13890.0 - CSX Transportation yard tower at Baldwin, Florida on July 29, 1987.
- ItemJMF23-15024.6 - Canadian Pacific Railway rail yard at Calgary Yard, Alberta in August 1990.