The SP&S Collection encompasses 6,286 documents relating to SP&S operations and indexed by station. Documents include correspondence, maps, leases, deeds, authorization documents, operating agreements and other document types for the period between 1890 and 1987.
The Spokane, Portland, and Seattle Railway Authority for Expenditure (AFE) Collection consists of 10,058 paper files. The contents document construction and modifications to the railroad and nearby structures, and include business and finance records, engineering drawings, maps, and correspondence. Records range from 1908 to 1968 and include some from the Oregon Trunk Railroad.
Spokane, Portland and Seattle Railway Historical Society
The Stan Kistler Collection consists of over 500 images of Northern Pacific Railroad Company equipment during the middle decades of the 20th century and 12 Northern Pacific public timetables from the 1930's through 1957, collected by Harold Stewart.
The Stephen Irwin collection is 152 railroad 5" x7" photographs each printed and captioned by photographer Ron Nixon from his collection of Northern Pacific railroad photographs.
The Stephen McDonald Collection includes Milwaukee Road pencils and a patch, photographs of Joseph McDonald (the donor's father) and copy of a newspaper article.
The Stephen S Eckman Collection is comprised of an Officers, Agents and Stations book dated 1965, a letter folder of three letters containing information and instructions for motor car inspections, a Great Northern Railway System Telephone Directory dated 1962 to 1969, a book labled "Station Agents Cash Book" but containing signal maintainers records of batteries, and seven SOO Line books containing demurage records.
The Steve Hauff Collection holds primarily Milwaukee Road materials together with a book of mechanical drawings for the Northern Pacific-Union Pacific interlocking plant at Tacoma, Washington.