Indian Railways — delay of current train by which not able to board connecting train

Address:

B-15 Yoganand co. housing society, 410210

Yesterday my mother boarded rajdhani from mumbai central (12951) seat no. A2/51/lb and departure time of the train was 08: 35.
But the train reached the delhi station at 9:40 due to which she could not board her another train which is new delhi to bareilly (20506) b5/12/lb
Who is responsible for this... I want refund for her new delhi to bareilly ticket