Breakfast is served after 8:00 am mostly (there are exceptions) as I have known since some of my relatives travelled on Mumbai Indore Duronto and they got down at Ratlam at 7:40 am and were served only bed tea with biscuits. They were told that breakfast is served after 8am though on Delhi Mumbai Rajdhani, breakfast could be served well before 8 am as it reaches BCT at 8:35 am.