by Bert Meinders

Created on: September 11, 2008

Strictly speaking, the steam carriage built (I think) in 1767 by Nicholas Cugnot was a tractor, designed to move artillery. With its boiler and engine mounted over, and supported by, the single front wheel it was a martyr to understeer, and ended its brief career by running into a wall. This was probably for the best, as metallurgy was not really sufficiently advanced to guarantee the safe confinement of steam at a high pressure to work an engine efficiently.

In the nineteenth century, gentlemen engineers like Richard Trevethick and Goldsworthy Gurney experimented with steam carriages and enjoyed some success with them until the Road Locomotive Act put a stop to such things. In France, Amedee Bollee and his sons, and the Comte de Dion made practical steam vehicles, Bollee's L'Obeissante of 1878 dealing with the problem of a differential by having a separate engine for each rear wheel.

During the early years of private motoring, the steam car offered significant advantages over its infernal-combustion-powered counterpart. A steam engine produces its maximum torque when starting, and needs no clutch or gearbox. It is quiet, smooth-running and easy to control. It can, with little modification, use a variety of fuels, and in the beginn9ing of the horseless carriage era there were more engineers and mechanics versed in steam engines than in petrol engines.

They had their weaknesses, however. A noncondensing engine needed frequent stops for water, preferably clean. Condensers were expensive and bulky. A boiler could be dangerous, and a Stephenson boiler, the simplest and cheapest suitable type, took an hour or more to raise a full head of steam from cold. The Serpollet water-tube boiler could be ready in five or ten minutes from cold, but had no safety margin for low water.
Most steam cars had their crankshafts integral with the rear axle, greatly increasing unsprung mass to the detriment of ride and handling. Fuel consumption was usually high. The introduction of the Rolls-Royce 40/50 in 1906, and the Ford Model T two years later, marked the point at which the petrol-engined car reached a level of performance and refinement that effectively rendered the steam car obsolete.

The Doble of 1927 demonstrated the peak of steam car achievement. It was silent, comfortable, handsome and practical. Its water-tube boiler took just ninety seconds to reach working pressure from a cold start and required no special attention. It was fast, capable of ninety miles per hour (also in reverse!). It was also preposterously expensive, both to buy and to run.

Steam trucks lasted longer, especially in Britain. Again, they were quiet, and could blast effortlessly up hills which had petrol trucks grinding noisily along at five or ten miles per hour. Sentinel, Thorneycroft and Foden were especially well-regarded.

Then the diesel engine got smooth and powerful, and its higher thermal efficiency gve it supremacy. Sic transit gloria mundi.

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