The Campbell-Railton Blue Bird was Sir Malcolm Campbell's final land speed record car.
His previous Campbell-Napier-Railton Blue Bird of 1931 was rebuilt significantly. The overall layout and the simple twin deep chassis rails remained, but little else. The bodywork remained similar, with the narrow body, the tombstone radiator grille and the semi-spatted wheels, but the mechanics were new.
Most significantly, a larger, heavier and considerably more powerful Rolls-Royce R V12 engine replaced the old Napier Lion, again with supercharger. This required two prominent "knuckles" atop the bodywork, to cover the V12 engine's camboxes.
Source: Wikipedia, 2013