The proposed mega show of the Trinamul Congress on Sunday at Brigade Parade grounds is likely to witness a thin attendance from north Bengal districts, considered to be a BJP stronghold, as Mamata Banerjee party's plan to bring its supporters in good numbers ran into railways' refusal to provide two trains.

Trinamul focused on two BJP strongholds — north Bengal and Jungle Mahal. A Trinamul source said the party's initial plan to bring at least 20,000 people from north Bengal districts was thwarted when the railways refused to provide two trains even after the party had deposited the security money of Rs 22 lakh on February 29.

According to plan, the trains would have brought party workers to Calcutta on March 9 and taken them back after the rally on Sunday.

"We planned to bring 10,000 people by two trains from Cooch Behar, Jalpaiguri and Alipurduar. As the trains were cancelled, most of our party workers failed to come to Calcutta," said a Trinamul leader.

He said that a few buses were arranged, but a large number of north Bengal party workers refused to turn up for the hectic road journey of around 16 hours.

"As of Saturday morning, only 600 party workers from north Bengal districts have reached Calcutta by boarding crowded general coaches of a few trains. Though lakhs from south Bengal districts will be enough to flood the ground, attendance of people from north Bengal in good numbers was politically vital," the leader added.

For any political party, it is essential to bring at least five lakh people to fill the Brigade Parade grounds. This is the first rally by Trinamul at Brigade Parade grounds since it came to power in 2011. The only Brigade rally Trinamul held since 2011 was before the 2019 Lok Sabha polls but it was a gathering of several Opposition parties.

"That is why we want to make it the biggest political rally in eastern India," said an Abhishek Banerjee aide.

Unlike previous Brigade rallies, Trinamul this year decided to set an example by making it the biggest rally ever in the city. There would be three large stages connected by two ramps measuring 330 feet and 240 feet to be used by Mamata and Abhishek while delivering speeches.

The core theme of Sunday's event will be Bengal rising and people roaring against the BJP's "zamindari (feudalism)".