Utilising other zone trains inside Tamilnadu has become a norm in SR. Though no train is run by SR in MS SA route, this CR is running.
Other examples include SCR train in NCJ SBC, SWR train in SBC KIK, CR train in YPR TEN, SWR train in SBC MV, SWR train in SBC TN, SWR and CR trains in YPR PDY routes. No SR train in these routes but other zones are running trains inside TN area!!!