The project announced Monday involves building a light rail line as opposed to a heavy rail line. Heavy rail lines have strict operating schedules involving signaling and safety issues, causing them to be more expensive to construct and operate than light rail lines.

Light rail lines are less expensive to build than heavy rail lines, which must be built underground when running through suburbs, costing more than $200 million per mile. The light rail line will be mostly above ground and would cost about $85 million per mile to build.

New Carrollton officials were in favor of a mostly underground, heavy rail line that would not be visible from homes in the city and would not affect these homes.

"I live on 87th Avenue, and my house shakes and my front door vibrates already just from the trucks going by," said Mayor pro tem Sarah C. Potter. "The city did not want anything above-ground to be built closer to the houses."

At a press conference with the Takoma-Langley Crossroads Development Authority, Glendening said the state's department of transportation would fund and construct the 14-mile, $1.2 billion rail project.

"For almost 30 years there has been an agreement that we need an east-west expansion of the Metro system to connect Montgomery and Prince George's counties," Glendening said. "To be most effective, Maryland's Purple Line must be built inside the Beltway. It will take thousands of cars off the roads."

The state Congress approves its next federal transportation-funding bill in 2003, and the Purple Line project will be included on the bill in order to qualify for federal funds.

However, Mahlon G. "Lon" Anderson of AAA Potomac said too much money was being spent on mass transit and not enough on roads, given that 95 percent of travel is done by car and only 5 percent using mass transit.

The Purple Line would circle the District, running parallel to the Beltway.

The Purple Line is expected to be completed in 2012 and include stations in downtown Bethesda, Chevy Chase Lake, West Silver Spring, Silver Spring, Takoma/Langley, Riverdale and New Carrollton and two stations at the University of Maryland in College Park.

Potter said state officials had told the city that the line would not be built for another 20 to 25 years.

"I think the state has made the wrong decision," said New Carrollton City Councilman James H. Fippin. "We wanted something that was below-ground, something non-interrupting without added noise and aggravation. I think this was a hastily made decision."

Fippin said the city had not been told that a decision about the line was going to be made so soon.

More than 40 groups, including the Chesapeake Bay Foundation, the Sierra Club, the National Center on Addiction and Substance Abuse and the Bethesda-Chevy Chase Chamber of Commerce, have publicly supported the Purple Line project.

The Sierra Club ran radio advertisements in September featuring a character called "Metroman" who needed help getting money for the Purple Line.

"Without the Purple Line, you now have to go through about 16 stops to get from the Bethesda area to College Park or New Carrollton," wrote Leor Galil of Bethesda in a letter to the Washington Post on Oct. 25.

The debate among members of Montgomery County's Planning Board was whether to support an inner or outer Purple Line.

The inner line the governor supported will connect Bethesda with College Park and possibly New Carrollton and Tysons Corner, Va.

The outer Purple Line would have connected White Flint to Wheaton before connecting to New Carrollton. The outer line would have been mostly underground.

The outer Purple Line was projected to take more traffic off the Beltway. However, an inner Purple Line would be more convenient for working-class and minority residents living in inner Beltway communities, said Tom Hucker, director of Progressive Maryland, a group that supports working families.

Harry Sanders of the Montgomery County Transportation Planning Review Task Force said he preferred the inner line model.

"An outer Purple Line would serve big parking lots, not inner cities and universities," he said.

Natalie Goldberg, another member of the task force, said she would have preferred the outer Beltway version and said there is no transit alternative for people wishing to take this route.

E-mail Christie Chapman at cchapman@gazette.net.