Maoists triggered a blast on the tracks in West Midnapore district early today, killing at least 20 passengers and leaving over 150 injured.
Following is the chronology of Maoists' targeting trains in West Bengal, Jharkhand and Bihar.
Apr 22, 2006 - Maoists lay siege to a passenger train in Latehar for eight hours.
May 2008 - Maoists lay siege to a passenger train in Latehar for five hours.
Nov, 2009 - Maoists blow up railway tracks in Simdega district in Jharkhand derailing a passenger train killing two persons and injuring 38 people.
October 27, 2009 - Maoists detain Bhubaneswar-New Delhi Rajdhani Express for eight hours during a bandh called by the People's Committee Against Police Atrocities (PCPA).
May 19, 2010 - Maoists trigger landmine blast on railway tracks near Jhargram in West Midnapore district injuring two drivers of a goods train and leaving the engine damaged.
May 20, 2010 - Fourteen oil tankers of a goods train derail and catch fire after Maoists blow up railway lines between Dighwara and Pipra stations in Bihar under Muzaffarpur-Narkatiyaganj section of East Central Railway.
May 22, 2010 - Two persons, including a policeman, travelling in the Tatanagar-bound Steel Express, injured in crossfire between Maoists and joint forces at Banstala station in West Midnapore district.