The Stanley Steam Engine, built in Newton, Massachusetts, has only 13 main moving parts. The engine was coupled almost directly to the car's rear axle, eliminating the need for a transmission. The Stanley engine had 2 cylinders, with 4in. bore and 5in. stroke. It was, however, a double-acting engine; that is the steam works against either side of the piston. At 30 miles per hour the Stanley Engine made only 350rpm with the smoothness of a conventional 8-cylinder gasoline engine. The engine made only 200 revolutions for each mile of travel. Steam was furnished by a fire tube boiler (wrapped with pianowire) consisting of 750 tubes. Heat for the boiler was supplied by a special burner in which gasoline, kerosene, or a mixture of the two could be burned.
In the 1890's, the Stanley brothers were engaged in making photographic dry plates in their factory at Newton, Massachusetts. This business was later sold to the Eastman Kodak Company. In the fall of 1896, they began to make drawings of a steam automobile. The Mason Regulator Company made their first engine, and the first Stanley car was completed in September 1897. In the spring of 1899 the Stanleys sold their business and the purchasers, soon after, split their interests and organised two steam car companies - The Mobile Company and The Locomobile Company. Subsequently, the Stanleys bought back the Newton plant and all the patents. The Stanley brothers manufactured cars until their retirement in June 1917, when they sold The Stanley Motor Carriage Company to a Chicago investment firm which controlled the affairs of the company until 1924. At this time it was resold to a newly formed concern called The Steam Vehicle Corporation of America. The Newton plant was disposed of by the new owners and headquarters transferred from Newton to Allentown, Pennsylvania, but no cars were ever produced there. The end of the Stanley Steamer came in 1925.