"Combining steam power with an automatic control system, a new method of propelling, trucks and buses as been developed. It includes a high-pressure steam generator producing up to 2,800 pounds of steam per hour at a pressure of 1,000 pounds per square inch. Electric ignition provides instantaneous starting.
The inventor claims that steam pressure of 900 pounds per square inch can be generated in about two minutes after the burner starts. The flow of oil to the burner and the flow of water to the generator are proportioned automatically in accordance with steam temperature and pressure conditions. At a certain temperature, or a certain pressure, the control system cuts off the burner. Heavy fuel oil, costing from two to four cents per gallon, may be used. The inventor's plans call for use of a final direct drive, with the engine mounted over the rear axle. No clutch, transmission or universal joints are contemplated between the steam engine and the point where the steam is used. The automatic controls are said to make the system explosion proof. The inventor proposes to use a four-cylinder engine in conjunction with other mechanism, all of which would have only 10 percent as many moving parts as the ordinary gasoline or Diesel engine used in trucks and buses.
Automobiles, trucks and buses registered in the United States in 1940 reached a record total of 31,468,887."
Source July 1941 Popular Mechanics Magazine