How? After arrival of Mail, CDO has almost 16 hrs for maintainance & shunting of rakes. Neither do these trains run drastically late that this schedule is affected. Even if you exclude 2-3 hrs for shunting from station to yard & back, then still it has 13 hrs for attention & normal PM is done in 7-8 hrs max. & If its not being done properly then its fault of CDO, not timetable or rsa.