Thomas Clarkson was better-known as a maker of steam commercial vehicles, particularly buses, than of passenger cars. In 1902 Clarkson moved to Chelmsford and made a few steam cars powered by 12hp 2-cylinder engines. They were usually known as Chelmfords, and most had bodies of the sation bus variety, with inward facing seats. Few were made, and Clarkson concentrated on steam buses. At its peak his fleet in London alone numbered 173 vehicles. He stayed in business until the mid-1920s.