This collection includes a great many objects, documents and photographs of the Brooks Locomotive Works, later the American Locomotive Company (ALCO).  This includes work tools, a fire fighting apparatus from the plant,  the plaque commemorating the death of Brooks founder Horatio G. Brooks, photographs, documents, and other ephemera.

The Museum also operates the ALCO/Brooks Railroad Display, located at the Chautauqua County Fairgrounds on central Avenue (accessible from Walldorf Road), about a mile from the museum.  The Display has three major pieces, of which the most important is  Brooks Locomotive #444,  built in 1916 and operated by the Fletcher Granite Company. It was donated to the Historical Society of Dunkirk in 1986, and is now on permanent display