Khardah station on Monday turned into a battleground between men and women passengers, pelting each other with bricks and stones.

The trigger: converting three of a nine-coach ladies special Matribhumi local into general compartments and allowing men to board them.

At least eight passengers, including two women, and 11 policemen and a woman constable were injured.

The incident led to a disruption on the Sealdah-Ranaghat line that lasted for more than four hours. More than 40 local trains had to be cancelled and over 100,000 passengers were forced to seek alternative modes of transport.

Train services normalised around 12.40pm after police resorted to lathi-charge and fired tear gas shells and arrested four people, including a woman.

Mamata Banerjee had flagged off the Matribhumi ladies special local between Sealdah and Ranaghat in 2010 when she was the railway minister.

A railway official said they found in a survey that only 30 per cent of the coaches remained occupied during rush hours while other locals on the same route ran overcrowded. He said the railways had received several requests from men asking for the introduction of general compartments in the ladies special local.

Another official said the railways had followed the usual protocol of newspaper advertisements and sending press releases announcing that some coaches of the Matribhumi local would be marked as general and men would be allowed to board them.

Similar arrangements had been successfully implemented in the Bandel and Howrah sections on August 5.

"We have arrested the people after they damaged the level crossing gate on Khardah Station Road," Barrackpore commissioner Niraj Singh said. "At least 11 policemen and a woman constable have been injured."

The blockade and subsequent violence forced the railways to withdraw its order for the time being and evening Matribhumi locals from Sealdah and Ranaghat ran without general coaches.

On Monday, the Sealdah-bound Matribhumi local had left Ranaghat station at 7.38am with railway officials announcing that three middle coaches and the vendor compartment from now on would be marked as general coaches.

The train had a smooth run till Barrackpore when women passengers started boarding the earmarked coaches and asked men to get off the local.

"Women passengers had sought the RPF's help at Barrackpore and Titagarh stations," a rail official said. "But they were told about the change and the train left the stations after some delay."

By the time the train reached Khardah around 9am, most women passengers waiting on the platform had been alerted by others about men boarding some coaches.

When the local pulled into the platform, some women barged into the middle coaches and allegedly dragged some men out of the coaches while a group of women squatted on the tracks. "This is our train. Since the introduction of the train we have been reaching the city without having to jostle for space or seats with men," Kaberi Mondal, one of the 200-odd women passengers who had blocked the tracks, said. "If the railways convert some coaches into general compartments, this train will become like any other train."

The blockade continued for around two hours till GRP officers from Barrackpore announced that the railways would reconsider the proposal to allow men to board Matribhumi locals.

As the protesting women got off the tracks clapping and cheering, some men got down from the platform and sat on the tracks, demanding that they be allowed to travel on Matribhumi locals.

"Daily, we cling to the doors while travelling on locals while women stretch their legs over seats on a Matribhumi local," said Amit Sadhukhan who takes a local to the city every day. "We were allotted only three compartments while the remaining six were reserved for women. But they still have a problem."

Sadhukhan works at a private firm on Rafi Ahmed Kidwai Road.

As more men joined the demonstration, someone from among a group of women standing on the platform started pelting the protesting men with stones, the police said. By 12.15pm, eight passengers had been injured and several policemen trying to stop the two warring sides suffered cuts and blows. A woman RAF constable was wheeled out of the station into an ambulance after a stone hit her on the head.

The police escorted two women to safety after they suffered injuries. While one had a cut on the forehead, the other fell unconscious after a brick hit her. Three men suffered head injuries.