There was a Fairfield fisher body plant located adjacent to the railroad tracks right where the railroad tracks cross RT 4, north of Symmes Street and east of RT 4 It was built in 1948, and closed in 1988. It was right where Bentley World Packaging is located today. Don't know if any of the current building is part of the old plant or not, but it was 1.3M square feet in size. Don't know what bodies they built there. I would guess it was 15 miles NNW of the Norwood Plant.
This is a little writeup about the plant in the butler county history page.
Fisher Body operated in Fairfield Township and Fairfield from 1947 through 1988. Plans for the plant west of Dixie Highway (Ohio 4), north of Symmes Road and east of the railroad were announced by General Motors April 6, 1945, before the end of World War II. When it opened in September 1947 it was part of the Fisher Body Division, producing parts for GM vehicles. Plant expansions were started in 1954 and 1960, after which the complex included 1.5 million square feet of operations on 108 acres. Employment rose to the 4,200 to 4,500 range in the early 1950s and fell to 2,500 before the plant closed. After August 1984, it was known as the Hamilton-Fairfield stamping plant of the Chevrolet-Pontiac-Canada Group (CPC). Nov. 6, 1986, GM announced corporate cutbacks which included the closing of 11 plants employing 29,000 workers. Operations at the Hamilton-Fairfield plant ceased Aug. 31, 1988, with about 100 GM personnel remaining until the end of December 1989 when the property was acquired by Panda Motors Corp., whose plans for its use never materialized. Panda placed the complex on sale in May 1992. During the lifetime of the plant, the Baltimore & Ohio Railroad (later Chessie and CSX) serviced the GM operation from its Wayne Yards, which was located just south of Symmes Road