Within the next three months, Metrobus commuters in Alexandria will get less service than they are getting now, but both Metro and Alexandria officials believe the cutbacks will be relatively painless.

The changes will be made primarily in the morning and evening rush hours and will reduce Alexandria's annual Metro operating subsidy by an estimated $240,000.

Metro's board of directors approved the cutbacks last week, to be effective in February and March. The cutbacks, requested by the Alexandria City Council as a cost-cutting measure, were the subject of a public hearing Oct. 4.

The curtailments will reduce the number of morning buses in Alexandria by seven, and the number of afternoon buses by 13.

Following are the changes that were approved; dates for implementing the changes are to be announced later.

Rounte 6, South Fairlington-Park-fairfax - Three variations of the route (6E, 6J, 6K) to be consolidated into two (6A, 6B), permitting fewer buses. A proposal to eliminate some service between Pendleton Street and the Alexandria-railroad station was dropped.

Route 7, Lincolnia-North Fairlington - Route 7C from Shirley Duke to Washington to be discontinued. Service will be provided by the new route 6A.

Route 8, Shirley Duke - The Quaker Lane part of the 8X route to be discontinued.

Routes 17, 18, 37 and 29, Shirley Highway - Proposals to eliminate service to Landmark shopping center during off-peak hours will not be carried out.

Route 19Y, Huntington - The current 10 trips from National Airport to the Hoffman Building will be reduced to six.

Route 26C, Crystal City Loop - To be discontinued and replaced by Alexandria Senior Citizen Trolley.

Route B1, Carter Barron-Hoffman Building - To be maintained on a reduced schedule only as far as Crystal City, with service from Crystal City to Hoffman Building discontinued.

Bush Hill Building service - Two morning and evening trips will be provided by a new route, 18 C, a variation of the existing route 18B.

Schedule changes - A total of 30 trips, at least sevev originating in the morning from the Springfield area of Fairfax County, will be discontinued. Most of these 30 trips are on routes 7, 8 and 18. A total of 17 other trips on these same routes will be rescheduled to take up the slack from the discontinuances.