The TRW 500 was introduced by Triumph Motorcycles in 1942 as a military motorcycle. Powered by a 499cc parallel-twin engine, it was capable of delivering approximately 17hp through a 4 speed manual transmission. Designed primarily for military use, it distinguished from other civilian Triumphs by its mechanical simplicity, high reliability and ease of maintenance under adverse conditions. Although it lacked high performance, it was notable for being the only post-war Triumph with a side-valve engine and for having been exported in large numbers to various Allied armed forces.