Canadian National Railway has upped the amount of money it will contribute to help communities deal with the increased rail traffic that would come with its proposed purchase of the Elgin, Joliet & Eastern Railway, but it still is less than half of the amount called for by a regional planning group.

After initially offering $40 million, CN said Wednesday it will pay as much as $60 million to help fight traffic delays and other problems that would result from its plan to shift more trains to the rail line that runs in an arc from Waukegan to Joliet to northwest Indiana. That represents 20 percent of the $300 million CN would pay for the EJ&E if the purchase is approved by the federal Surface Transportation Board.

E. Hunter Harrison, the railway’s president and chief executive officer, called the $60 million “an unprecedented proportion for any railroad control transaction,” in a statement released Wednesday.

“Clearly, CN is stepping up to the plate to mitigate significant environmental issues in this case,” Harrison said.

But in a letter filed with the Surface Transpiration Board before Tuesday’s deadline for public comment on the transaction, the Chicago Metropolitan Agency for Planning called for CN to contribute $150 million.

CN declined to comment on the agency’s request.

Under state and federal law, the agency is responsible for producing the region’s official plan for land use and transportation in Cook, DuPage, Kane, Kendall, Lake, McHenry and Will counties.

The agency is asking the Surface Transportation Board to require that CN prepare a binding agreement for dealing with the negative impacts of the acquisition.

“Five counties in (the agency’s) planning area are intersected by the EJ&E line, and all seven of our counties will be affected by the proposed acquisition,” Executive Director Randy Blankenhorn said. “Maintaining metropolitan Chicago’s economic status as an international freight hub is an important priority.

“Mechanisms exist ... to move forward in a true spirit of public/private partnership,” he said. “That means helping communities address their very real concerns, not pitting them against one another.”

Last month, CN filed a petition in federal appeals court asking for the Surface Transportation Board to make its decision before the end of the year. The EJ&E’s current owner, U.S. Steel Corp., has said it will not extend its purchase agreement with the railway beyond Dec. 31.

Many local leaders in DuPage County and other suburban areas argue that the acquisition would dramatically increase train traffic along the EJ&E tracks and negatively affect communities through which they run. Others leaders, especially those in west suburban Cook County, support the plan, which they say will reduce traffic congestion.