Me travelled in 12696, TVC-MAS superfast express, till salem(SA)… I’ve observed a thing that Tracks till shornur(SRR) bye pass makes heavy noise.. When it entered in tamilnadu no sound, no disturb, but great speed.. I’ve feel the same when I travelled in 12625, TVC-NDLS Kerala SF express… My question is that, Why Kerala track make much noice?? Why tamilnadu track don’t make noise?? Anyone plz reply