4 High-Speed Rail Plans Offered : Transit: One proposal for LAX-Palmdale line calls for 125-m.p.h. trains riding electomagnetic cushion of air.

Four private partnerships submitted proposals to a county transportation panel Tuesday to build a high-speed train line between Los Angeles International Airport and Palmdale, including a futuristic “mag-lev” line that would propel passengers at speeds up to 125 m.p.h. on a cushion of air.

Responding to a separate request for bids to build an east-west rail line across the San Fernando Valley, the four partnerships also proposed building an aerial line over the Ventura Freeway--rejecting a mostly underground route that county officials had favored.

The 71.8-mile LAX-Palmdale line is designed to have 14 stations and run alongside the San Diego, Golden State and Antelope Valley freeways. In requesting bids, the Los Angeles County Transportation Commission specified that trains travel at a minimum of 60 m.p.h. and carry 4,000 passengers per hour.

City and county officials hope the line will ease congestion at the Los Angeles International Airport by giving airline travelers the option of flying from the giant regional airport the city hopes to build someday on Palmdale land it has been buying for years for that purpose.

The line would also improve mobility throughout the region by hooking up with other proposed rail projects.

In requesting the non-binding bids, the commission did not specify the type of technology preferred for either line, so that private companies could determine which technology is the most viable to build and operate.

The Transportation Commission staff declined to release the construction estimates offered by the private companies, saying they must be kept confidential because it will be easier to negotiate final bids if the companies do not know what the other firms offered. The Transportation Commission has estimated the cost of the project at $4 billion.

The commission will review the LAX-Palmdale proposals in January. The partnerships offered to use a range of technology for the LAX-Palmdale line, including automated light rail, monorail and an advanced light rail project similar to the Metro Blue Line.

However, only the group led by Thyssen-Henschel, the rail engineering unit of the German steel and engineering group Thyssen AG, proposed using the magnetic levitation technology that has been tested in Japan and Germany but to date not put into passenger service.

Mag-lev trains have no wheels and are propelled by electromagnetic force on a cushion of air, creating little noise or pollution.

The other partnerships submitting proposals were led by Matra Transit, a Chicago-based subsidiary of a French urban transit company, Bombardier Inc. of Canada, and Morrison Knudsen, an Idaho-based construction and engineering firm. Morrison Knudsen formed a partnership for the project with Hughes Aircraft of Los Angeles.

But before any passenger can ride the LAX-Palmdale line, the Transportation Commission will have to overcome financial, technological and political hurdles.

The commission’s 30-year transit construction plan provides only $1.56 billion for the LAX-Palmdale line starting in 1998--less than half the commission’s estimate of the cost.