"Jewellery, four stolen mobile phones and a country-made pistol were recovered from them," a GRP official said.
Om Prakash, Bhupendra and Ombeer used to rob passengers in locals as well as express trains, he said.
On the night of April 21, passengers of two trains, one starting from Delhi and another bound for the national capital, were robbed of valuables, cash and assaulted by a group of six unidentified armed assailants in Moradabad and Ghaziabad.
"We are scanning the records of such robbers, who have earlier arrested for loot in trains. Police are also closely monitoring the footages of CCTV installed at railway stations," officer also added.