The Congress workers took out rallies and stopped trains at several stations across Uttar Pradesh on Thursday to express their ire against summons issued to former prime minister Dr. Manmohan Singh in connection with the coal blocks allocation scam.

The Congress workers, led by party's Uttar Pradesh chief Rita Bahuguna Joshi, stopped the Howrah-Amritsar Express at Lucknow's Charbagh railway station for over an hour on Thursday. Congress workers also staged a 'Rail Roko' protest. Earlier , Congress president Sonia Gandhi led a solidarity march to Dr. Singh's 3, Motilal Nehru residence in the national capital, and said that the party was outraged on hearing the news of the summons being served by a court on the former prime minister.

Protests against summons to MMS: Rita Bahuguna Joshi stops Howrah-Amritsar Express at Charbagh railway stn in Lucknow pic.twitter.com/op2PZNJX7T March 12, 2015

"Dr. Manmohan Singhji is our former prime minister. He is known not only in our country, but throughout the world as being a person of integrity and probity. The Congress Party is fully behind him," she said . A special CBI court in Delhi had summoned the former prime minister, former coal secretary P.C. Parakh, industrialist Kumar Manglam Birla and three others in the coal blocks allocation case on Wednesday.

The court summoned them on alleged charges of criminal conspiracy, breach of trust and under various provisions of the Prevention of Corruption Act. They have all been asked to appear before the court on April 8. The case pertains to the allocation of the Talabira II coal block in Odisha to M/s Hindalco in 2005, when Dr. Singh was holding the coal portfolio.