Nayjivan Express starts from Ahmedabad towards Baroda at 6:30 am in the morning, moving at an average speed of 50 km/h. The distance between Baroda and Ahmedabad is 100 km. At 7:00 am in the morning the Howrah Ahmedabad express starts from Baroda and moves towards Ahmedabad at 40 km/h. At 7:30 am, Mr. Shah, the station controller, realizes that both the trains are running on the same track. How much time does he have to take action to prevent the collision?