AUGUSTA – As ridership on Amtrak’s Downeaster train increases and Maine’s highways grow more congested, Gov. John Baldacci is ordering a plan for expanded passenger rail service to interior and coastal communities.

Baldacci’s executive order, which he signed Friday and announced Monday, also calls for clearer economic development plans near train stations along the existing route of the Downeaster, which connects Boston’s North Station and Portland.

The passenger train stops in Old Orchard Beach, Saco and Wells in Maine; Dover, Durham and Exeter, N.H., and Haverhill and Woburn, Mass.

Baldacci’s executive order could set the stage for passenger service north of Portland to Brunswick and Lewiston-Auburn, with seasonal and excursion links to Rockland, Bethel and other destinations in Maine.

“Every month the Downeaster is breaking new ridership records,” Baldacci said. “We’ve made the trains faster and better. The Downeaster is bringing new energy to downtown economic development in Old Orchard, Saco and other communities. It’s time to head north.”

The Downeaster finished the fiscal year that ended in June with the biggest increase in ridership since the start of the service in 2001. The train’s 329,265 passengers was an increase of 31 percent over the previous year, accounting for the biggest on a percentage basis anywhere in the Amtrak system during the period, a spokeswoman said.

Baldacci’s order directs the Northern New England Passenger Rail Authority and its executive director, Patricia Douglass, to work with the state Transportation Department and review all of the existing expansion studies and present by Dec. 1 “a clear set of next steps for investment north of Portland.”

“I’ve asked for an action plan to get year-round scheduled service to Auburn and Brunswick. We may use Amtrak, or we may build a commuter service, but there should be no doubt that we will get there,” Baldacci said.

The governor also directed Martha Freeman of the State Planning Office to help guide the economic development that will be happening near the Downeaster’s existing stations.

“We need a regional approach to smart development strategies that will help communities direct growth into old mills and other assets near current and future train stations,” Baldacci said.

Baldacci’s order cites several reasons to anticipate growing demand for passenger rail services, including increasing gasoline prices, a federal mandate for state action to mitigate increased air emissions from highway projects, and further congestion on Maine highways, especially portions of Interstate 95.