The actor who portrays Aditi's friend and sometime crush: Avi (Aditya Roy Kapoor) and the actor who portrays Aditi's fiancé: Taran (Kunaal Roy Kapoor) are brothers in real life.
When Bunny and Naina are boarding the train, Bunny picks up Naina's luggage along with her book. A second later we see him boarding the train while Naina is behind with her book still in hand.