WASHINGTON – Amtrak's ridership increased 55 percent from 1997 to 2012, and much of that growth was driven by the nation's 100 largest metro areas, including several in California, according to a report by the Brookings Institution.

State-supported Amtrak corridors in California saw big gains over 15 years. Modesto and Fresno, connected by the San Joaquin service, saw passenger increases of 75 percent and 84 percent, respectively.

Ridership in Sacramento, an anchor for the San Joaquin Corridor, as well as the Capitol Corridor to San Jose, nearly tripled.

Major cities served by state-supported passenger train corridors in other states, including Washington, Missouri, Illinois, Pennsylvania and North Carolina, posted large ridership gains during those 15 years.

"Simply put, short-distance routes are the engines of Amtrak ridership," said the report by the Washington, D.C.-based center-left research group.

Yet Amtrak, which has required a federal operating subsidy since its inception in 1971, faces automatic spending cuts and efforts to reduce or eliminate federal support.

Amtrak isn't exempt from an across-the-board array of federal spending cuts, called sequestration, that's due to go into effect today. Throughout its history, the passenger railroad has never had a dedicated source of funding, and its annual subsidy has varied according to the whims of Congress and the White House.

"Amtrak is used to these irregular budgets," said Robert Puentes, a senior fellow at Brookings and one of the report's authors. "I think they're going to be in better shape than other agencies."

In a statement, Amtrak said it had anticipated the potential funding reductions and built them into its budget.

"Amtrak is planning to take actions to allow it to withstand a funding cut and not cut service," the statement said.

Amtrak posted record ridership of 31 million passengers last year. The 55 percent increase in riders in the past 15 years outpaced the growth in other travel modes, according to the Brookings report.

It far exceeded a 16.5 percent increase in miles traveled by car, a 20 percent increase in airline passengers and even a 26.4 percent increase in regional transit riders.

Though the total number of people who travel by car, plane and transit far exceeds those who travel by train, the Brookings report said the increase in Amtrak ridership indicated that the public was embracing passenger rail.

"All three modes do carry larger aggregate quantities of people, but these growth trends serve as evidence of changing attitudes toward train travel," the report said.

The increases were especially pronounced in states that subsidize short-distance trains between major cities. The country's 100 largest metro areas generated almost 90 percent of Amtrak's ridership, the report said.

Amtrak contracts with 15 states to operate 21 routes, and those states contributed $191 million to operate the trains in 2011.

Corridors of 400 miles or fewer have the most riders and require the lowest subsidies, but virtually all of them still lose money.

Neither Amtrak nor the states could rely entirely on federal funding to run these trains, and Puentes said the shift toward state funding of passenger trains might result in better service on both short- and long-distance routes.

"This is the kind of conversation that has to happen in these states right now," he said. "It's not going to come out of Washington."

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