In which medium would sound move the fastest

Sound moves the fastest through a solid medium. Since the molecules within a solid are compactly or closely placed, so sound travels faster through it. It has already been experimentally proved that sound travels 17 times faster through a solid steel than through the air. This shows that sound can travel faster though a solid than through liquid or gas. Another way to prove that sound travels faster through solid is, if we place our ear in the railway line, then we can hear the sound of the train coming whereas the sound cannot be heard through the air.