SWR should explore biweekly via GTL, RU and biweekly via TK, KJM (bypassing YPR). Remaining 3 days, there can be weekly/ biweekly MAS UBL Via GTL/ TK.
This can be by combining all UBL/ VSG to MAS trains and deriving a TT such that trains reach MAS by 1700 and leave MAS by 2000. If PF issues are there, it can go to MS or Tambaram.
With such arrangements, one can get daily UBL MAS as well 4 days a week VSG MAS.