Tuesday 16th September 1947

John Cobb averaged 394.19 mph (634.39 km/h) (385.6 & 403.1) over the measured mile in both directions to take the world land speed record driving the Railton Mobil Special at the Bonneville Salt Flats. The Railton was powered by two supercharged Napier Lion VIID (WD) W-12 aircraft engines. These engines were the gift of Betty ‘Joe’ Carstairs, who had previously used them in her powerboat Estelle V. Multiple engines was not a new technique, having already been used by the triple-engined White Triplex and the Railton Special’s contemporary rival, Captain Eyston’s twin-engined Thunderbolt. With the huge powers thus available, the limitation was in finding a transmission and tyres that could cope. Reid Railton found a simple and ingenious solution to this by simply splitting the drive from each engine to a separate axle, giving four wheel drive.