Moscow City Court handed prison terms of 15 to 18 years to Islam Khamzhuyev, Fail Nevlyutov, Mansur Umayev and Mansur Edilbiyev, natives of Russia’s troubled North Caucasus region.
Prosecutors said they had tried to attack the Sapsan train in summer 2011, state news agency Itar-tass reported. A lawyer for the accused said the defense would appeal.
The Kremlin is struggling to contain an insurgency in its mostly Muslim North Caucasus that continues in the wake of two wars between Moscow’s security forces and Chechen separatists in the region.
Muslims seeking to establish an Islamic state claimed responsibility for an attack that killed 27 people on a Moscow-St Petersburg train in 2009, a suicide bombing that killed 37 at Moscow’s busiest airport in 2011 and bombings on the Moscow metro that killed 40 in 2010.
Earlier this year, Russia jailed 10 people – four of them for life – for the 2009 bombing on the Moscow-St Petersburg line.