CPI(M) leader Basudeb Acharya, who also chairs the parliamentary standing committee on railways, maintained that the strategy adopted to earn more revenue appears to be unethical. "If there is any increase (in freight charges) it should be done at the time of the budget," he said. "After the budget there should not be any change in classification."

A look at government data shows that rail freight revenues grew much faster than freight loading. In 2005-06, total freight collections rose 18% to Rs33,480 crore, while freight loading, the amount of freight carried, rose 10% to 635 million tonnes.

In the case of foodgrains, for instance, the Food Corporation of India, another government entity, absorbed the additional freight costs but eventually transferred the higher costs to the Central exchequer. The government, in turn, accounted for this in the form of higher food subsidy payments.

Similarly, the rail ministry is expected to have earned an additional Rs500 crore last year by upgrading the freight classification for fertilizers.

"Many letters have been written to the finance ministry but they have not been able to force any substantial reversal in freight charges," said another official.

Private players have not been as lucky. Recently, limestone traders based in West Bengal and Jharkhand have said that many businesses in the state had to shut shop due to the recent change in freight classification.

The changes made in the first week of this month, mere weeks away from the presentation of the new Rail Budget, has meant that the railway freight charge has increased by about Rs 2,200 per wagon, the Dankuni Stone Dealers Association said in a petition to Acharya earlier this month.

"At this juncture, thousands of businessmen and labour(ers) who are solely dependent on the Railways will be jobless," the petition said.