Amtrak is dropping its opposition to the hotly debated sale of a suburban Chicago railway line.

Amtrak officials said Wednesday they had reached agreement on the continued use of Canadian National Railway tracks in Chicago and will not oppose CN's attempt to purchase the EJ&E Railway.

Some residents in the Northwest Indiana communities of Griffith, Schererville and Dyer remain staunchly opposed to CN's plan to buy the EJ&E, contending that increased train traffic on the railway would gridlock their communities.

Many Chicago area suburbs also bitterly oppose CN's plans to more than triple traffic on the EJ&E. The EJ&E runs in a 198-mile loop through Chicago's suburbs from Waukegan, Ill., to Gary.

CN Chief Executive Officer E. Hunter Harrison said the agreement with Amtrak represents his railroad's commitment to implement a "comprehensive voluntary plan" to mitigate the impact of the EJ&E acquisition.

The federal Surface Transportation Board still must rule on the acquisition, which could happen by the end of this year or early next year.

Amtrak had worried Canadian National would stop maintaining its other Chicago-area tracks if it purchased the EJ&E. One of those is the St. Charles Air Line, which runs in Chicago from Union Station to McCormick Place and south to Carbondale, Springfield and other Illinois cities.

Amtrak operates several trains on the route. CN has agreed to keep maintaining those tracks.

But Amtrak spokesman Marc Magliari said ending its opposition to the purchase isn't the same as active support. He said Amtrak is taking a "neutral position" on the $300 million sale.

The Associated Press contributed to this story.