1. It was not ludhiana but Amritsar.
2. The driver tried to stop after accident and brought down the speed to almost 10 kmph but guard informed that people are pelting stones, so to save the passengers inside, he took the train to Amritsar station which was just 2 kms from the spot.
The driver did his duty, can't imagine what would have happened if the train had stopped. It was obvious that people were very much angry (and its natural) as they had lost their beloved ones and in that anger...
more... they could have done anything to the train, crew members and passengers. So the driver did best what he could.