I don't think travel time can be reduced in CR further for Mumbai Chennai trains as the speed increase is already reflected in the daily trains while other trains passing through is not reflected like SBC and Hyd bound trains apart from weekly scheduled trains.
22159 Pune 1620/25 SUR 1955/2000 262km Wadi 2235/40 150km zone change slack of 20 mins is provided.
12163...
more... Pune 2210 Sur 200 Wadi 410
22157 mail Pune 255/655 Wadi 945
Slack has been carried forward to SCR after RU to Puttur section and Arkonnam Chennai section. Wadi to Ru 540 km is given 9hrs for most trains and if increased to 130kmph and implemented in TT then the travelling time will decrease over SCR by 30-60mins.