Russia launched a terrorism investigation on Tuesday after a bomb derailed an express train between Moscow and St Petersburg, overturning carriages and injuring dozens of passengers, officials said.

The head of Russia’s Federal Security Service (FSB) linked the attack late on Monday to an insurgency in the south of Russia around Chechnya, where Moscow has been fighting a long rebellion against its rule.

But Interfax news agency quoted an unnamed investigator as saying the homemade bomb was similar to one used by two Russian nationalists to blow up a train near Moscow two years ago.

Sixty passengers and train crew were hurt in the derailment near the village of Malaya Vishera, about 500 km north of Moscow and 170 km from St Petersburg, a Russian Railways spokeswoman said. About 250 people had been on board.

“We heard two explosions, then the train put on the brakes suddenly,” said a conductor on board the train who did not want to be identified.

“The train shook. A panic started,” he said. “We smashed out the glass and helped the passengers out ... The worst damage was in the restaurant car. That is where most of the casualties were,” he told Reuters.

The derailed train was an overnight service travelling on one of the country’s busiest rail routes, heavily used by businesspeople and foreign tourists.

The bomb was planted on a bridge over a road and left a crater about 2 metres across, witnesses said.
“The train accident was caused by a homemade explosive device,” Sergei Bednichenko, chief prosecutor for Russia's North West district, told Channel One television. “A criminal case has been opened under article 205, clause 3, that is terrorism.”

The train came off the tracks just after crossing the bridge and and at least three carriages were tipped onto their side.

Link to insurgency?
Interfax quoted an FSB official as saying the bomb contained 2 kg of explosive material.

FSB chief Nikolai Patrushev said it was part of a pattern of violence that included a spate of attacks on security forces and officials in the North Caucasus region around Chechnya.