ROCKLAND – Maine Eastern Railroad says it will expand its excursion service to four days a week between Rockland and Brunswick, starting Saturday.

Last year, Maine Eastern Railroad, which already operated a freight service on the state-owned Brunswick to Rockland line, was asked by Gov. John Baldacci to transport passengers from Brunswick to the Lobster Festival in Rockland.

This year, Maine Eastern Railroad decided to expand the service.

It plans to run trains between Brunswick and Rockland from Thursday through Sunday between July 2 and Sept. 2. Weekend-only service will be offered from Sept. 2 through Oct. 31.

Gordon Fuller, vice president and chief executive officer of Maine Eastern, said the company has the capacity to sell 17,000 seats this season. Fuller said he expects about 70 percent of those seats to be purchased.

Fuller and Maine Eastern Railroad President Wes Weiss say their passenger train service’s future may hinge on rail service being extended north from Portland.

But state transportation officials say passenger rail service between Portland and Brunswick is still about five years away from becoming a reality.

The state will need about $60 million to upgrade the line to make it safe to carry passengers, said Tracy C. Perez, a policy specialist with the state Department of Transportation’s Office of Passenger Transportation. Perez said the state will investigate federal funding.

“We are definitely looking at extending it, but like anything, it is going to require a major investment,” said Patricia Douglas, acting executive director for the Northern New England Passenger Rail Authority.