Keystone Motor & Mfg. Co
This was an unconventional steamer which had a 3-cylinder engine in each rear wheel hub, fed by steam from a tubular boiler mounted in the body. The company planned to make light cars and heavy trucks using this system.
[1]Georgano, G. N., Encyclopedia of American Automobiles, (New York, E. P. Dutton & Co., 1968), p. 110.