At least 55 trains were running late and six cancelled due to dense fog in parts of north India on Tuesday morning, a railway official said.
As many as 22 trains were rescheduled on Tuesday and two were cancelled for Wednesday, the official said.
The trains cancelled on Tuesday included the New Delhi - Howrah Poorva Express, New Delhi - Bhubaneshwar Rajdhani Express, Amritsar - Howrah Mail, Jodhpur - Varanasi Marudhar Express, Delhi Jn - Azamgarh Kaifiat Express and Varanasi - New Delhi Kashi Vishwanath Express.
Varanasi - Jodhpur Marudhar Express and New Delhi - Varanasi Kashi Vishwanath Express were cancelled for Wednesday.