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.