The accused, identified as Bhupender Kumar, a native of Gaya in Bihar, was caught from platform number 3-4 during routine checking, Government Railway Police (GRP) Inspector Tripurari Pandey said.
Four kg of opium, worth Rs 80 lakh in the international market, was recovered from him, he added.
The consignment was being ferried from Gaya to an agent in Jaipur in Rajasthan, Pandey said.
A case has been registered and a hunt launched to nab the other members of the gang, he added.