Metro officials announced plans yesterday to increase subway service on the Red Line starting next month, ending a controversy that had caused concern among Montgomery County officials.

The moves, which include more frequent rush-hour and nonrush-hour service, were linked to Metro's plans to open a seven-mile Red Line extension to the Shady Grove terminus in Montgomery County in December. Some shifts in Red Line service are to be delayed because of shortages of rail cars.

Cleatus E. Barnett, a Montgomery County member of Metro's board of directors, said the county supported the revised plan, despite the delays. "We understand the necessity for this, and we agree to it," he said.

In drawing up the new plan, Metro officals set aside an earlier proposal that had called for less frequent Red Line service. Barnett had denounced the previous scheme as "a degradation" of service.

The transit authority also announced several other moves yesterday, including a plan for extended rail service during the Thanksgiving, Christmas and New Year's holidays. The Metro board also proposed major changes in bus routes in eastern Fairfax County and Alexandria.

Metro General Manager Carmen E. Turner was given a 5-percent pay raise by the board, bringing her salary to $81,900 a year. Arlington County Board Vice Chairman John G. Milliken, the Metro board's chairman, praised Turner, saying she had done an "outstanding job" since taking the job last year.

The first increase in Red Line service is scheduled for Nov. 25, when trains are to start running every six minutes during evenings, weekends and other nonrush-hour periods. Officials described the shift as a major improvement over current 10-minute intervals between Red Line trains at nonrush hours.

Increases in rush-hour service are to be delayed until Jan. 6, about three weeks after the Red Line is extended to the Shady Grove terminus near Gaithersburg. Officials attributed the postponement to a series of delays in testing new rail cars.

Starting Jan. 6, trains will run every four minutes at rush hours along the most heavily used portion of the line between the Grosvenor and Silver Spring stations. Rush-hour service now is provided every five minutes.

Between Shady Grove and Grosvenor, officials said, trains will run every eight minutes at rush hours, an improvement over the 10-minute intervals planned when the Shady Grove extension opens Dec. 15. At nonrush hours, trains are to run every 12 minutes between Shady Grove and Grosvenor.

In another key step March 17, rush-hour service is to be increased to provide trains every three minutes between Grosvenor and Silver Spring and every six minutes between Shady Grove and Grosvenor.

Because of rail car shortages, officials said crowding may occur temporarily on some Red Line trains after the Shady Grove extension opens in December and, again, after bus routes are revised to serve Red Line stations on Jan. 27.

Under the plan for extended holiday service, officials said the rail system will stay open until midnight on Sunday Nov. 25, for passengers returning from Thanksgiving trips. On four other Sundays -- Dec. 2, 9, 16 and 23 -- trains are to run an extra hour, until 7 p.m., to accommodate shoppers. Trains are to run until 2 a.m. on New Year's Eve and midnight on New Year's Day.

The Metro board scheduled a public hearing Nov. 27 on the proposal to alter Metrobus service in eastern Fairfax and Alexandria. The proposed shifts are aimed partly at increasing bus service to the Huntington rail station.

Cutbacks were proposed on routes 9, 11 and 27, which link Fairfax and Alexandria with the Pentagon, National Airport and the District. More than 10 new or revised routes were recommended to connect the Huntington station with Mount Vernon, Rose Hill and other areas.