LOS ANGELES -- Competition to provide passenger train service between Southern California and Las Vegas is heating up, even though the last such effort to carry fun-seekers across the Mojave Desert was derailed by a lack of customers.

For years, backers of a proposed magnetically levitating train running from Disneyland to Las Vegas have traded barbs with a rival project that would take tourists from the California desert town of Victorville to the Strip on a high-speed train dubbed DesertXpress.

The "maglev" supporters call DesertXpress the train to nowhere because it wouldn't fully reach Southern California's population centers. Privately funded DesertXpress counters that a levitating train is a pie-in-the-sky concept that would cost billions in taxpayers' money.

Recently, two new companies have been touting party trains that promise to shuttle people from downtown Los Angeles to Las Vegas on existing track. They're fighting with each other over who came up with the idea first as they bid for railroad contracts.

Of the 36.4 million visitors to Las Vegas last year, 26 percent came from Southern California and a majority used ground transportation to get there, according to the Las Vegas Convention and Visitors Authority.

Even with a slump in Las Vegas tourism due to the recession, airline flights fill up on weekends and congestion on the main highway between the two regions is legendary.

On some days, the 270-mile, four-hour drive between Los Angeles and Las Vegas can stretch into a six-hour or longer grind in heavy traffic in the middle of nowhere. In real life, the groom in last year's bachelor party farce, "The Hangover," probably wouldn't have been able to speed back to LA in time for his wedding.

"There is demand for another form of transportation since these other forms are so congested," said Mary Riddel, an economics professor at the University of Nevada, Las Vegas.

Last month, Las Vegas Railway Express announced plans to acquire double-decker passenger cars and convert them into casinos on steel wheels. The proposed "X Train" would feature a sports bar, sushi bar and entertainment to keep passengers amused during the roughly 5 1/2-hour ride. An executive said a round trip on the "X Train" would cost about $99, and floated the possibility of allowing riders to gamble as soon as the train crosses the state line into Nevada. He predicted the train could start running by mid-2011.

A website for the train, featuring the disco funk sound of The Gap Band's "Party Train," shows computer renderings of the cars' interiors looking a lot like the lobby of a hotel casino.

Not long after X Train's announcement, a rival claimed the idea of a luxury train was stolen by X Train executives who looked at the business plan for the Z-Train (Its motto: "Once Z-Train starts, Z-Excitement Never Stops").

"We think we have the best plan, we're going to be most viable in the long term," said Bruce Richardson, a spokesman for Z-Train.

Richardson said Z-Train plans to target upscale passengers by providing gourmet meals, art exhibits, book signings, fashion shows, among other things. Tickets would cost about the same as airline tickets.

"We believe brand X is looking for a customer looking for a coach seat and a beer," Richardson said. "We're going to offer something that'll rival a private jet experience. We believe that our services are going to be so desirable that when the train gets to Las Vegas it's not about why it took so long to get there, it's a question of 'Oh, do we have to get off the train already.'"

The companies are locked in a legal battle while they face a bigger challenge in trying to convince Union Pacific Railroad, which owns a majority of the tracks between Los Angeles and Las Vegas, to let them use the right of way. Concerned about growing publicity about the party trains, Union Pacific issued letters last week denying it has had any serious negotiation to allow either company to operate on its tracks.

Union Pacific also does not endorse and will not allow gambling on its tracks, Jerry Wilmoth, the railroad's general manager of network infrastructure, wrote in the letters.

"If UP doesn't want gaming then we won't do it," said Michael Barron, chairman of Las Vegas Railway Express.

The concept of a party train to Nevada's gambling meccas isn't new.

Since 1992, a tour agency in Northern California has organized an annual winter "Fun Train" from the San Francisco Bay area to Reno, allowing passengers to dance and drink along the ride.