No matter how many fine dining options you may have in your area, there’s something about sitting down in a diner that can’t be matched. Their menus are models of American comfort food, from meatloaf to patty melts. The coffee cups are bottomless. There’s usually a toothpick dispensary at the register.

Many diners across the country have one additional identifying trait: They’re shaped like a train car, a sleek and narrow compartment that looks like it belongs on a set of tracks. When and why did this style choice become synonymous with diners?

In a piece for Atlas Obscura, Anne Ewbank shed some light on the practice. The early 20th century saw a rise in entrepreneurs who were interested in meeting the need for casual dining establishments for people hurrying to or from work. Their ambitions had evolved from the lunch wagons of the late 1800s, which provided shelter from weather by putting up awnings or letting people sit inside on stools.

City ordinances, however, made such operations a little tricky: Many food wagons needed to be permanent fixtures in order to avoid the narrow operating hours mandated by communities. Rather than hire a contractor or lease an existing commercial space, people opted to order prefabricated, mobile carts that could be shipped to their location by rail or towed by truck. These dining cars became known as “diners.”

Like the pop-up locations of today, the diners could appear virtually overnight. Most were delivered in one piece; others were modular, requiring minimal assembly, and could offer a greater variety of styles and seating capacities. For small business owners, their affordability and convenience made it possible to strike out on their own. Some manufacturers even offered to repair fixtures by having the diner shipped back to the factory.

The look became so intertwined with fast-dining that some owners recycled old train cars to capture the aesthetic. Today, even diners built from scratch often mimic the narrow, elongated shape so familiar to patrons—a design now borne out of choice rather than necessity. It's a curious bit of history, and one worth pondering the next time you grab a toothpick.

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