PORTLAND – The Downeaster passenger rail service, two months into operations between Massachusetts and Maine, seems likely to exceed Amtrak’s ridership expectations for 2002.

Mike Murray, executive director of the Northern New England Passenger Rail Authority, said that more than 20,000 passengers rode the Downeaster in January, typically the Northeast’s slowest month for train travel.

Amtrak has estimated that 320,000 people will use the Portland-to-Boston service this year.

“If we can move 20,000 people in a low ridership month,” Murray said, “it leads us to have very positive expectations about what is to follow.”

Figures released Friday provide an early glimpse at ridership and revenue for long-awaited train service.

A total of 34,306 passengers rode the train from Dec. 15, the first day of service, through Jan. 31. The trips generated $550,854 in ticket revenue. Murray said he expects the Downeaster to cover its operating costs.

Wayne Davis, chairman of TrainRiders-Northeast, has long maintained that officials were underestimating the demand for renewed passenger service between Portland and Boston.

“The January figures are amazing,” Davis said. “People are using it for transportation, not entertainment.”

Murray was also upbeat about ridership for February. Reservations show that seats on the most popular runs this weekend and next week, during school vacation, are largely sold out.

The Downeaster offers four round trips daily between Portland and Boston. The most popular run is train 685, which leaves Boston at 6:15 p.m. and arrives in Portland at 9 p.m.

The next most popular run is train 682, which departs Portland at 8:45 a.m. and gets into Boston’s North Station at 11:30 a.m.