See also: Lunch Counter Lingo
The fact is that hardly any diners were built from old railroad cars. They were just made to look that way. It all started in Providence, Rhode Island in 1872 with Walter Scott's horse drawn lunch wagon. He sat inside, and customers ordered sandwiches, pie, boiled eggs and such through open windows in the side. He sold to night workers, mostly from the Providence Journal. Soon lunch wagons appeared all over.
Many towns either banned them or placed restrictions, forcing them to be off the street from 10 am to 8 pm. So some got the idea to find a vacant lot, take off the wheels, and hook up to utilities. They were now restaurants, and immune from the lunch wagon restrictions. The diner was born.
New Jersey has more diners than any other state and is sometimes called the 'diner capital of the world.'