Bhopal: A pipe bomb was used for the blast in the Bhopal-Ujjain passenger train, Madhya Pradesh Chief Minister Shivraj Singh Chouhan said on Wednesday.
A timer was also used in the Tuesday bombing near Jabri station which left 10 persons injured, he said.
The Madhya Pradesh Police later on Tuesday arrested three suspects who were going to Hoshangabad district's Pipariya in a bus.
"They had reached Bhopal from Lucknow by the Pushpak Express on Tuesday morning and placed the bomb on the rack above the seat in the passenger train around 7.30 a.m. The terrorists had set a two-hour timer," the Chief Minister said.
According to Chouhan, the bomb caused less damage as it was placed above and the effect could have been greater if it was under the seat.
The suspects, all from Uttar Pradesh, had planned to escape to Lucknow from Pipariya.