The Pacific Surfliner, running from San Luis Obispo, Calif., down the coast to San Diego, is Amtrak’s second-most popular route, with nearly 2.7 million passengers last year.

But one thing sets it apart from most other trains run by the federally funded passenger railroad: It’s paid for by the state of California.

California is among 14 states – including Maine – that fund corridor service that Amtrak wouldn’t otherwise provide.

U.S. Sens. Frank Lautenberg, D-N.J., and Trent Lott, R-Miss., today are expected to announce introduction of legislation that would, among other things, encourage more state investment in Amtrak by making federal matching funds available.

The sweeping bill – similar to one that passed in the Senate 93-6 last year but was never voted on in the House – calls for $12 billion in federal funding over the next six years. Many Amtrak supporters believe it has a better chance this year with Democrats in control of Congress.

But one aspect of the bill is relatively uncontroversial. The idea of matching funds for state investment in Amtrak is one that both supporters and critics of the railroad have embraced – and something states like California believe is long overdue.

As for Amtrak itself, “states are our future,” President Alex Kummant said last week. He said a matching program for capital investments, along with making Amtrak “more user-friendly” for states, is essential if Amtrak is to capitalize on growing demand for intercity rail.

Even without such matching funds, states have been stepping up. The biggest player, California, contributes $73 million for the Pacific Surfliner and two other trains it runs jointly with Amtrak.

Illinois last year doubled its annual subsidy to Amtrak to $24 million. The increase followed several years of double-digit growth in the number of riders on routes connecting Chicago with St. Louis, Carbondale, Ill., and Quincy, Ill., and allowed Amtrak to offer much more frequent service.

Other states that subsidize Amtrak service are Maine, Michigan, Missouri, New York, North Carolina, Oklahoma, Oregon, Pennsylvania, Texas, Vermont, Washington and Wisconsin.

Outside of Amtrak’s busiest route – the Northeast corridor from Boston to Washington – the state corridors are the biggest success stories. They provide a stark contrast to the railroad’s long-distance trains, which many critics believe should be eliminated because they are costly and attract comparatively few riders.

State involvement is healthy, “as opposed to having our trains totally planned by a centralized, monopolistic, Washington, D.C., organization,” said Joseph Vranich, a former Amtrak spokesman who is now one of its most vocal critics.

But states can do only so much without the availability of matching funds for capital improvements, said Jason Tai, director of public and intermodal transportation for the Illinois Department of Transportation.

“Unlike other modes of transportation, be it highways, transit or even waterways, there is no dedicated substantial funding for rail. There is an unlevel playing field,” Tai said.

The Lautenberg-Lott legislation would allow states to fund capital rail projects with up to 80 percent in federal funds. States would continue to pay operating costs, but their arrangements with Amtrak would become more standardized.