However, our investigation is still under progress and very soon we will nab the accused,' Kamraj said.

Police launched a hunt for those who hurled stones at the Swarn Shatabdi Express in which Gandhi was travelling from Ludhiana to New Delhi Tuesday evening. Gandhi had taken a train, shunning the usual helicopter ride, as part of austerity measures initiated by the Congress party.

One of the arrested boys said: 'We throw stones at trains everyday as we derive fun out of this activity. We did not know that Rahul Gandhi was travelling in the train on that day.'

Though no one was injured in the train attack, the window panes of three coaches, C-2, C-4 and C-7, were damaged.

One stone pierced the twin glass window of the Shatabdi Express and landed inside coach C-4. The glass panes of two other coaches cracked.

However, none of the stones hit the C-3 coach in which Rahul Gandhi was seated near the window.