The blast in the Bhopal-Ujjain passenger train that left 10 people injured was carried out using a pipe bomb, Madhya Pradesh Chief Minister Shivraj Singh Chouhan said on Wednesday.
The explosion took place near Jabri station on Tuesday and the terrorists also used a timer, he said.
The Madhya Pradesh Police arrested three suspects who were going to Hoshangabad district's Pipariya in a bus.
"They reached Bhopal from Lucknow on Tuesday morning and placed the bomb on the rack above the seat… The terrorists had set a two-hour timer," the Chief Minister said.
Hailing from Uttar Pradesh, all the suspects planned to escape to Lucknow from Pipariya.