American Frog & Switch Co., 1028 Main Street, Hamilton, prospered for nearly 50 years during a boom in American railroading and two world wars. Its products were standard steel frogs and switches, track supplies and other railroad specialties. (In railroading, a frog is a device placed at the intersection of two tracks. It permits a train to cross a perpendicular track.) The one-story, 40,000 square foot plant was on the northwest side of Main Street between Lawn Avenue and the Belt Line Railroad at Haldimand and Cereal avenues, Its property, which originally extended 1,000 feet along Main Street, ran northeast to Park Avenue.
The original factory measured 100 by 300 feet, and was served by a spur from the Belt Line Railroad. AF&S was organized May 31, 1901, by Hamilton and Cincinnati businessmen. It was incorporated in June 1901. Local owners sold the business in 1934 to Taylor-Wharton Iron & Steel Co., High Bridge, N. J. The "shop accomplished vital war production during World War II," a newspaper reported. "Besides work for trackage at domestic war plants, required specialties were rushed to foreign countries for use of allies in running of new rail lines and repair of damaged ones." When the war ended in 1945, American railroads went into decline and with them the markets served by AF&S. Between 1945 and 1949, some of the property fronting on Park Avenue was sold and houses built on the land, reducing the company's holding to only seven acres. In April 1949, officials announced the factory would close May 6, 1949, production would be moved elsewhere, costing 42 jobs, and the property would be sold. Within a few months, the shop was demolished and the land occupied by a strip shopping center, bank and other businesses.