A group of armed robbers, who boarded Rapti-Ganga Express train between Manjhi-Rivilganj stations around midnight, shot and critically injured Uday Kumar before looting 44 kg silver and cash from him and four other traders, Muzaffarpur's Superintendent of Police, Railway, Shashikant Jha, said.
Kumar has been admitted to a hospital, he said, adding an FIR has been lodged and a hunt is on to nab the robbers.