Nothing will happen. It is just another gimik. Their main moto is to replace Sleeper coaches with AC Coaches and earn more money. Nothing will be seen in reality. Ultimately 5 to 10 mins travel time will be increased in these years timetables, and that time will get reduced then giving reason of 160 kmph speed upgradation nothing else. Don't expect overall average speed of these train after conversion to full AC will be between 130 to 160 kmph.