Its slowed down because it touched Coimbatore where as the ernakulam superfast did not enter coimbatore...both trailing cst-cape from thirupattur but ernakulam superfast over taking it by bypassing cbe, but still kcvl express trailing it upto ERN.So it would be better to overtake more stoppage cst-cape before salem....otherwise use the same path of ernakulam superfast...Kottayam people really need a connection for this train, so better change the timing of vachinadu from 5 to 5.30 or change the scedule to reach kochuveli train at ernakulam around 4.30