PORTLAND – Ridership is up on the Downeaster passenger train that runs between Portland and Boston, and rail officials attribute the rise to faster travel times and rising gasoline prices.

The number of riders was up 8 percent in May over the same month in 2004, 12 percent in June and 9 percent from July 1 to July 22.

“We have seen three solid months of growth,” said Patricia Douglas, acting executive director of the Northern New England Passenger Rail Authority, the agency that operates the Downeaster. “The resurgence is impressive.”

The authority has been working to draw more passengers since ridership slumped after the service’s first year, when many people rode the train because it was new. The train began service in December 2001.

Those efforts may now be paying off.

The number of people traveling on the train has jumped since travel time from Portland to Boston was reduced in April to two hours and 30 minutes, a savings of up to 15 minutes. The trip takes less time because of faster train speeds, track improvements and shorter stops at stations.

Rising gasoline prices also may have caused more people to switch from their cars to the train, Douglas said.

The rail authority also received good news out of Washington this week when Congress approved a transportation bill that assures the federal government will continue to subsidize the service until 2009.

Since the service began, Maine has used mostly federal funds to subsidize the Downeaster, which offers four round trips a day. The funds were due to run out this year and Maine taxpayers were scheduled to pick up the entire cost, about $5 million to $6 million annually.

But the transportation bill, which was signed into law Wednesday by President Bush, allows the state to continue using federal funds to pay for 80 percent of the subsidy.

That will save Maine taxpayers $3 million to $4 million annually and give Maine officials more time to figure out how to pay for the train when the federal money runs out. Gov. John Baldacci plans to appoint a task force this fall to look at long-term funding issues.

Like other forms of public transportation, the Downeaster will never pay for itself from ticket sales, rail authority officials say. But more passengers means fewer tax dollars, and they say ridership figures show the service has become a viable transportation alternative, with 700 to 900 one-way trips a day.