New Delhi: Fog is causing 42 trains to be delayed in the Northern Railway zone. Puri-New Delhi Purushottam Express, Pratapgarh-Delhi Padmavat Express, and Gaya-New Delhi Mahabodhi Express, according to Northern Railway, are all 4 and a half hours behind schedule. Darbhanga-New Delhi is among the other trains that are tardy. The Bihar Sampark Kranti Express, the Malda Town Delhi Farakka Express, the Kathgodam Jaisalmer Ranikhet Express, and the Kamakhya Delhi Brahmaputra Mail.