The Bentley Historical Library acquired the collection of Claude T. Stoner in 1977, and digitized many of the images in the historic railroading collection, which are now available through the Bentley Image Bank.
According to Telltale Photographs: The Stoner Railroad Collection by May Davis Hill, Stoner documented “virtually every aspect of railroading, particularly as it related to Michigan.”
In addition to the photographs, there are letters, printed materials, and more concerning the Ann Arbor Railroad, the Grand Trunk Western Railroad, the Manistee and Northeastern Railway Company, the Michigan Central Railroad, the Pere Marquette Railroad, and Ephraim Shay. You can see an overview of the collection here, which is open to the public.