In the scene where Shah Rukh Khan and Kajol are stuck in the train compartment, Kajol's suitcase bursts open and she hurriedly stuffs her clothes back into it.
When Shah Rukh sits on the compartment floor, there is clearly nothing behind or underneath him. But in the very next scene, he pulls out Kajol's bra from under him.
During the climax, the railway station where Raj and Kuljit have a fight is shown to be 'Apta' (as seen on the signboard). Apta is a small station near Mumbai and is more than 1700 km away from Punjab where the plot is based.