Track improvements are on the way for the Amtrak Downeaster.

The Northern New England Passenger Rail Authority won a $20.8 million grant from the U.S. Department of Transportation for the Portland-to-Boston service.

Sens. Olympia Snowe and Susan Collins announced the award to the rail authority. Snowe, a member of the Senate Commerce, Science, and Transportation Committee, and Collins, ranking member of the Senate Transportation Appropriations subcommittee, wrote to Transportation Secretary Ray LaHood in support of the grant application.

The rail authority will use the funding for final design and construction of a second track in a congested area between Wilmington and Andover, Mass. The construction will allow intercity passenger trains to meet and pass other trains on the corridor.

The improvements will help improve mobility in Maine and New England, increase ridership and create jobs, the senators said in a joint statement.

The work is expected to strengthen the relationship between the rail authority and the Massachusetts Bay Transportation Authority and set the stage for faster and more frequent passenger train service in Northern New England, according to Patricia Quinn, executive director of the rail authority.

The project is part of nearly $800 million in projects to improve rail service in the crowded Northeast, and $2 billion going to rail projects in 15 states nationwide. It was money originally awarded to Florida but rescinded after the governor canceled rail plans there.

The changes could trim another 15 minutes from the running time, bringing the service closer to a goal of completing the Portland-to-Boston route in less than two hours, said Wayne Davis, president of TrainRiders Northeast, a rail advocacy group based in Portland.