CONCORD, N.H. – With passenger train service about to resume between Maine and Boston, a study group is beginning to look into whether it would be worth trying to restore other former passenger lines in New Hampshire.

A task force will meet Wednesday to study restoring passenger service from Boston to Montreal, with possible stops in Concord and Franklin, N.H. It would involve a line from Nashua to Merrimack and Manchester, and from Concord to Lebanon.

Peter Griffin, a member of the New Hampshire Railroad Revitalization Association, said he thinks the service could be part of a balanced transportation system and help unclog highways.

“I definitely feel it could happen,” he said. “I’m promoting this as something that can be part of a balanced transportation system, not something to take the place of what we already have, but to complement the road and air traffic systems.”

Christopher Morgan, rail administrator for New Hampshire’s Department of Transportation, said rail travel is likely, but he doesn’t know when.

“Someday it will happen,” he said. “I don’t know if it will be 20 years or 50 years, but I think it will happen, preferably in our lifetimes.”

Considered too costly, slow and impractical until recently, passenger train service is returning to New Hampshire and Maine as commuters complain about clogged highways and difficulties parking in Boston.

On Dec. 15 daily rail service begins between Boston and Portland, Maine, with three stops in New Hampshire. And by 2004 daily service is expected to be restored between Nashua and Lowell, Mass., which connects to Boston.

“Say you could take 10,000 cars a day off I-93. That would be fabulous,” said Nancy Girard, of the Conservation Law Foundation. “Just think of the pressure you’d take off that road, and all the congestion you’d eliminate.”