After 11 months of negotiations, the College Park City Council has accepted Metrorail proposals for cutting down on the noise that was expected to result when a planned subway line opens in the city in 1992.

The proposals, which also have been agreed to tentatively by county officials, call for extending the tunnel of the Green Line at the Calvert Road Metrorail station and shifting the track 40 feet away from the Calvert Hills neighborhood. The shift will allow for an earthen barrier to be built between the tracks and houses.

Residents of Calvert Hills objected to the original Metro proposal, saying tracks within 100 feet of their houses would be an eyesore, create excessive noise and lower property values.

The proposals, which must be approved by the Prince George's County Council and the Metro board, also call for building a 3 1/2-foot-high barrier as a protective device along the tracks at Calvert Road, in contrast to the 20-foot noise barrier proposed last year by the City Council. The higher barrier would have added $1.5 million to the cost of the line, a Metro engineer said.

The project engineer, Johann Sikkan, said a 20-foot barrier would only reduce the noise level one or two decibels.

"The wall would have to be 30 feet high to have any significant impact, and there we're only talking three decibels," said Tim Ayers, spokesman for County Executive Parris Glendening, who helped negotiate the compromise.