The Mac McColloch collection includes 1 spiral-bound photo album of locations on the Norhtern Pacific Railroad Company's Palouse & Lewiston and Central Washington branches operated by Watco, dated March 9-10, 2004; 1 spiral-bound photo album of Palouse WA; the Northern Pacific's Washington, Idaho, Montana line; and the abandoned Genesee branch; and 22 books on railroad operations, operation of railroad equipment and safety related materials.
The Maple Valley Historical Society Deposit includes of 85 digital photographs of Pacific Coast Railroad equipment and locations taken by Tom Kroutz between 1949 and 1952 and provided to Pacific Northwest Railroad Archive on a computer disc. A separate deposit was made of 82 digital photographs of Pacific Coast Railroad and other railroad subjects taken between 1909 and 1991 in and around Maple Valley by various photographers.
The Marijane Marceau Collection comprises Northern Pacific engineering records, documents and maps, Burlington Northern documents, Union Pacific maps, railroad employee union documents, and ephemera and calendars from a variety of United States railroads.
The Mark Gelhaus Collection includes documents, timetables, operating instructions, equipment manuals, maps, equipment registers, photographs and sound recordings produced between 1885 and 1994. Railroad represented include the Northern Pacific, Burlington Northern, Union Pacific, Southern Pacific, Milwaukee Road, Great Northern and other railroads. Many of these materials were accumulated by Michael D. Gelhaus and Al Bennett.
