One of the robbers, suspected to be on board the train, pulled the chain near Chirala at around midnight yesterday to stop the train, according to a spokesman of South Central Railway (SCR).
Some robbers then snatched the chains and other jewellery of the passengers through the windows in sleeper coaches, he said.
Four passengers complained about the robbery to Government Railway Police at Secunderabad station here this morning.
About 70 grams of gold jewellery was estimated to have been robbed, he said, adding, that full details of the incident were being gathered.