The Fleetwood Diner opened in Hagerstown, Maryland in 1938. Looks like a secondhand 1920s model, but it’s hard to be positive- O’Mahony was advertising a very similar model as late as the early 1940s. It was attached to a Fleetwood gas staion at 1000 (later 1004) West Washington St.
By 1945, it was Trucker’s Diner. Its name changed to the West Washington St. Diner in 1947, and closed in 1961.