Amtrak as well as its Downeaster passenger service between Maine and Boston have set new ridership records. The national high-speed rail operator says its trains carried more than 31 million passengers in the fiscal year ending Sept. 30. That marks the highest annual ridership total since Amtrak started operations in 1971. Records were also set in other regions of the country, including New England. Downeaster ridership rose 4.3 percent to more than 541,000 passengers. Ethan Allen ridership between New York and Rutland, Vt., was up 10 percent to more than 54,000 and the Vermonter from Washington to St. Albans, Vt., had 5.5 percent more passengers at 82,000. The Downeaster also set a ridership record for the fiscal year that ended June 30.