Question

you can hear the sound of an approaching train long before you see it by placing the year on the metal track why?

Answer 1

yes, we can hear the sound of the train by placing year when train comes the metal track vibrates because according to third law of motion action and reaction the train exerts high pressure that's why metal track vibrates and we can hear the sound.

Answer 2

Because speed of sound is more in solids than in gaseous .

Therefore railway track being solid propagates sound earlier than in gaseous air.