Is it possible to detect the approach of a train by listening to sound waves traveling through the tracks before seeing the train? If the elastic modulus is 2.0 x 10ⁱ¹ N/m², and the density of steel is 7.8 x 10³ kg/m³, how much faster is the speed of sound in the track compared to air, where the speed of sound in air (vₐᵢᵣ) is 340 m/s?