Crews are finally beginning work on the $35 million rail upgrade that will allow the expansion of the Downeaster passenger rail service to Brunswick.

United States Transportation Secretary Ray LaHood announced today that the U.S. Department of Transportation and the state of Maine have finalized a grant agreement allowing work to begin on the state-supported Downeaster Amtrak intercity passenger service.

After the grant was first announced last January, state officials said they expected construction to begin in early spring. LaHood in his press statement today did not explain the cause of the delay. He said the federal money would augment additional funds from the state to cover the project cost. LaHood did not say how much money the state has committed to spend on the project.

Patricia Quinn of the New England Passenger Rail Authority, which operates the service, could not be reached for comment.

The project includes the rehabilitation of 26.4 miles of existing rail lines owned by Pan Am Railways and the construction of two platforms.

The project, which is funded with federal stimulus funds, will also improve 36 highway-rail grade crossings and upgrade numerous wayside signals.

The project is scheduled to be completed in 28 months.

The Downeaster currently operates five daily round-trips between Portland and Boston.