Railways Ministry spokesperson Anil Saxena said several people have been rushed to nearby hospitals with injuries, and the casualties may go up.
While some states like Kerala and Telangana were badly hit by the strike, the impact was partial in Punjab, Haryana and Maharashtra
The main contest is between the CPI-M and the BJP in the February 18 assembly polls for 60 seats.
Prohibitory orders were imposed in Delhi and parts of Karnataka. Police kept tight vigil in Kerala. In Gujarat, 50 people were arrested for Thursday's violence.
Incidents of arson, firing and vandalism were reported from Madhya Pradesh, Rajasthan, Uttar Pradesh, Bihar and Punjab as protesters agitated against the dilution of the SC/ST Act.