The rescheduling came as close to 100 trains arrived here several hours behind schedule, some late by even a day.
The rescheduled trains included the Rajdhani and Duronto trains mostly bound for the eastern states, said a Northern Railway spokesperson.
The long delays and the change of departure timings caused inconvenience to passengers, especially to those who had to catch connecting trains from the city to carry on with their further journey.
The spokesperson said even as the foggy conditions subsides, it will take at least two to three days for normalcy to return.
Apart from the Rajdhanis, the late incoming trains today included the Shiv Ganga express from Varanasi, Magadh express from Islampur, the Amritsar Shatabdi express, Mahabodhi express from Gaya, Bihar Sampark Kranti express from Darbhanga, Farakka express from Malda Town and a special train from Patna which was running late by more than a day.