For the fifth straight year, Amtrak is chugging toward a record high for ridership, helped by high gasoline prices and congested highways and airports that seem to have encouraged people to keep their vehicles parked.

But America's rail network, which relies heavily on government funding, still has its headaches, and the biggest is funding. The service has never been out of the red since its launch in 1971, meaning it must rely on government handouts year after year.

In trying to hash out the federal budget for next year, Congress is weighing how much U.S. taxpayers should underwrite the passenger service. Amtrak has requested $1.53 billion, nearly twice the amount the Bush administration wants to give it. In the past, Bush has proposed giving the service nothing.

A House appropriations committee recently agreed to boost Amtrak's federal funding to $1.4 billion — a modest increase from the service's $1.3 billion in government help — while a Senate panel has endorsed spending $1.37 billion. But Bush has promised to veto any spending bills exceeding his budget requests, forcing Amtrak to slice service if the president makes good on his threat.

Amtrak says the elusiveness of stable funding holds it back, leaving it unable to commit to infrastructure improvements, get past having to use some equipment dating back half a century or add new rail cars it says it can easily fill on some routes.

The service also continues to be nagged by travel delays, mostly tied to having to share the tracks with freight haulers that own the rails and charge Amtrak a modest fee — $90 million in the last fiscal year — for using them. With freight traffic soaring in recent years, Amtrak's on-time performance slid to an average of 68 percent last year, its worst showing since the 1970s.

"There's room for improvement, and we're looking for it," said Marc Magliari, an Amtrak spokesman.