Jerry O'Mahony Diner Company
The Jerry O'Mahony Diner Company of Elizabeth, New Jersey, was a manufacturer of roadside diners from 1917 to 1952. The company produced some 2,000 of the long, narrow, primarily metal buildings, perhaps more than any other firm. Prefabricated in a factory and trucked to their locations, the diners resemble and are often confused with actual railroad rolling stock. The company's motto was "In our line, we lead the world".

History
Jerry O'Mahony (1890–1969) of Bayonne, New Jersey, is credited by some to have made the first "diner". In 1912, the first lunch wagon built by Jerry and Daniel O'Mahoney and John Hanf was bought for $800 by restaurant entrepreneur Michael Griffin and operated at Transfer Station in  Hudson County, New Jersey. The wagon helped spark New Jersey's golden age of diner manufacturing, which in turn made the state the diner capital of the world.

The Jerry O'Mahony Diner Company of Elizabeth, New Jersey, produced some 2,000 diners from 1917 to 1952.

Existing examples 
Only about twenty O'Mahony diners still exist. In the United States, the northernmost is Martha's Diner in Coventry, Vermont. The Miss Wakefield, originally Pat & Bob's in Albany, New York, was built in 1949, rescued from a junkyard there, and trucked to a new home in Sanbornville, New Hampshire. The Summit Diner, a 1938 model, is in Summit, New Jersey. The oldest Southern diner (non–stainless steel style) is believed to be the Hillsville Diner in Carroll County, Virginia. The Triangle Diner, a 1948 stainless steel O'Mahony original model, is located in the old town of Winchester, Virginia, and is being restored to how it appeared in 1948. The Triangle Diner is the oldest stainless-steel-style O'Mahony diner in Virginia. In 2007, Tommy's Deluxe Diner was moved from Middletown, Rhode Island, to Oakley, Utah, where it opened as the Road Island Diner. One of the original diners displayed at the 1939 New York World's Fair, made by Paramount Diners, is still in operation as the White Mana in Jersey City. Also in Jersey City is the Miss America, a 1942 classic stainless steel model, located next to the New Jersey City University campus. The Shawmut Diner of New Bedford, Massachusetts, was donated by its owners to the Bristol County House of Corrections in Dartmouth, Massachusetts, and will serve as a training facility for inmates.  TJ's (formerly the Point Diner) in Tamaqua, Pennsylvania, is a 1940 O’Mahony diner, although its exterior has been renovated and no longer has the stainless-metal look. The diner is in the Tamaqua Historic District.  Palace diner 1923,  in Gloversville New York.  

Overseas examples include the former Murphy's Diner from Cambridge, Massachusetts, now the '50s American Diner in Swadlincote, South Derbyshire, in the United Kingdom. A 1947 model operated as The Excellent Diner in Westfield, New Jersey, until it closed in 1995; shipped to Germany, it now operates at Disneyland Paris as Café des Cascadeurs (Café of the Stuntmen).

Pre-war Streamline Moderne-style diners
At least 26 pre-war Streamline Moderne-style O'Mahony diners (built between 1932 and 1941) still exist. These include the smaller 50' × 10' Mickey's Diner serial number 1067 in Saint Paul, Minnesota, which is one of several listed on the National Register of Historic Places; the 40' × 16' Collin's Diner serial number 1103 in North Canaan, Connecticut; and the 1938 Summit Diner in Summit, N.J. The Road Island Diner (O'Mahony Dining Car #1107) was added to the National Register of Historic Places by the National Park Service on August 21, 2009.