 The metadyne unit weighed about 3 tons, and consisted of three rotating machines, an exciter, a regulator and the actual metadyne machine, which were linked together mechanically.Electrically, the traction supply was fed into the machine, and the output fed the motors, without the need for starting resistances.The test train ran through much of 1935 and 1936, and was tried on nearly all of the electrified tracks on the Metropolitan line and the District line.