DES MOINES — A variety of factors may be behind a 4 percent drop in Amtrak ridership in Iowa, but some passenger rail advocates remain hopeful service will one day increase in the state.

The National Rail Passenger Corp., which operates as Amtrak, reported that 57,955 people boarded Amtrak passenger trains at Iowa’s six stations during the 12 months ending Sept. 30. That’s more than 4 percent down from the previous year and nearly 16 percent less than Iowa’s record ridership year of 2010.

The California Zephyr travels daily eastbound and westbound through Iowa, stopping at Burlington, Mount Pleasant, Ottumwa, Osceola and Creston. The Southwest Chief stops in Fort Madison.

Amtrak spokesman Marc Magliari blames the decline on more people driving due to low gasoline prices. He also thinks higher-performing vehicles lead more people to drive themselves.

“Our competition, for the most part, is driving, and as people buy newer cars that get better mileage, part of me wonders if people aren’t finding themselves driving because their cars are higher performing than they were 10 years ago,” Magliari told The Des Moines Register .

Iowa rail advocates also note Amtrak has cut its ticket agents at train stations, making it harder to buy at a depot.

“There are still people who come into the station wanting to buy a ticket and who maybe have never ridden Amtrak before,” Krebill said. “When there is no ticket agent, there is really no one there to answer questions and tell people how to get on a train and where to get on a train.”

Iowa’s ridership drop came even as national ridership remained steady and revenue climbed 2.2 percent over the previous year.

Rail supporters continue to push for expanded service, especially a route from Chicago traveling through Iowa City and Des Moines to Omaha, Nebraska.

Sen. Matt McCoy, of Des Moines, has long sought state funding for rush a route, and he said he’ll continue advocating for rail in his new position on the Polk County Board of Supervisors.

Krebill said there’s plenty of support for a line through Iowa linking Chicago to Omaha, and others have called for a line through Des Moines that links Minneapolis-St. Paul to Kansas City.

Des Moines lost its regular passenger trains in 1970.