The, Speed, Record, That, Will, Probably, Never, Be, BrokenIn this modern age, it's not often speed records stand for long; the production car speed record, for example, is often being broken and re-broken. But, on July 3, 1938, a speed record was set which remains unbroken even today. The now-famous steam engine "Mallard" reached 202 kilometers per hour (126 mph), a speed record for steam engines.