Raju Thapa, who hails from Nepal, was collecting trash lying near the railway track when a low-intensity crude bomb exploded, SP Hiralal said.
A police team reached the spot and found three more live bombs in the bag in which Thapa had collected the waste, the SP said.
He said that the bombs look like low-intensity "sutli bombs" or crude bombs.
The injured has been rushed to a hospital and police are probing the matter.