Red Line riders will enjoy the most frequent service and some of the least crowded trains on the Metro system under a rail car deployment plan approved by the transit agency's board of directors yesterday.

The decision followed a lengthy debate in which representatives from Arlington and the District unsuccessfully argued that the Orange and Green lines deserved more relief than the Red Line.

Under the new plan, "if you ride on the Green Line, you have to wait twice as long for a train and have a train that is 15 percent more crowded" than on the Red Line, said D.C. Council member David A. Catania, who represents the city on the board.

Chris Zimmerman, who represents Arlington, said the Red Line was greedy. "The Red Line has to get everything it can," he said.

Last month, Metro finally received the last of the 192 rail cars it ordered in 1998, but delivery ignited a dispute about which lines should get the additional cars. The new cars -- with their distinctive red-white-and-blue color scheme -- have gone into service as they've been delivered by the manufacturer. So far, they've been assigned to the Orange, Blue, Yellow and Green lines.

The final batch of 42 cars was supposed to be added to the Red Line, with the intention of increasing the number of rush-hour trains and cutting the time between trains in the downtown area from three minutes to 21/2 minutes.

Some Metro directors questioned that plan, saying it was developed two years ago and does not reflect current crowding conditions. "The case is clear that we are distributing rail cars in accordance with an old projection," said D.C. Council member Jim Graham, who cast the lone dissenting vote against the plan. "It seems to me we owe it to our customers to make the service as evenly provided as possible."

But the board chairman, Robert Smith, who represents Maryland, said Red Line riders have been patiently waiting for more rail cars. The Red Line, which starts and ends in Montgomery County and goes into the District, is the heaviest traveled of all the lines. Smith said the transit system should honor a commitment it made to the Red Line when the plan for the new cars was created two years ago.

As a compromise, Metro directors agreed to send just 34 of the new rail cars to the Red Line while adding eight other cars to the Red Line from the subway's pool of emergency spares. They agreed to take the remaining eight new rail cars and six others from the spare pool and send those to the Green, Blue and Orange lines. And they agreed to revisit the matter later this year and develop a policy under which rail cars would be regularly reallocated based on ridership.

With the changes approved yesterday, the most crowded line would be the Blue Line serving Franconia-Springfield, with an average 99 passengers per car. Following close behind is the Orange Line serving Vienna, which would carry 97 passengers per car. The Red Line serving Shady Grove would carry 89 passengers per car while the branch of the line serving Glenmont would carry 87.

In other developments yesterday, the board approved a plan to significantly increase advertising throughout the bus and rail system. Metro officials intend to wrap 100 buses and 20 trains in computer-generated vinyl ads from top to bottom and front to back, creating rolling billboards. They also will hang commercial banners inside stations, display animated commercials on subway tunnel walls and install video monitors on buses, in trains and in stations. In addition, the board approved the installation of automated teller machines inside stations as another way to generate revenue. Officials expect to collect about $5 million a year from the new commercial ventures.

Also, two new board members took the oath of office. Gordon Linton, the federal transit administrator under President Bill Clinton, was appointed by Montgomery County Executive Douglas M. Duncan (D) to represent the county on the board. Linton, 56, of Rockville, is a vice president of WageWorks Inc., a Bethesda company that administers commuter benefits, including Metro's Metrochek program. Linton said he would recuse himself from Metrochek issues. He fills the seat vacated by the death of longtime Metro board member Carlton R. Sickles.

Charles Deegan, chief of equipment maintenance in the Department of Public Works and Transportation for Prince George's County, was appointed by Maryland Gov. Robert L. Ehrlich Jr. (R) to fill the seat held by Decatur Trotter, who died this month. Deegan, 55, is also the president of the county's board of elections. He lives in Beltsville.

The board's decision allocates the last of 192 new red-white-and-blue rail cars that Metro purchased to cope with growing ridership.