The traction motor sounds on the Metropolis trains on line M1 execute a 380 Hz-665 Hz-1290 Hz progression on acceleration. There is also a brief 1340 Hz-1240 Hz sound that is made in the late acceleration phase. Unlike the trains in New York however the trains decelerate with a repeating 1340 Hz-1240 Hz sound. This is because in Warsaw synchronous phase sounds are also used; in New York it’s entirely asynchronous.
