OVER THE PAST 14 years, Alexandria's schools have moved steadily and remarkably smoothly through the intricate process of racial desegregation. Throughout the same years, equally remarkbly, the quality of education there - particularly in the secondary schools - has risen notably. A great share of the credit for this double achievement is owed to Dr. John D. Albohm, superintendent of the city's schools since 1963, who announced the other night that he will shortly retire.

Dr. Albohm had a lot of help over those years. He worked under a succession of school boards that enjoyed a talent for reasonable compromise. The city's voters were willing to pay for the improvements that made the new integrated schools more effective than the old segregated ones; the key to the Albohm policy was to accompany each step in racial policy with visible strengthening of the teaching programs. A good many people in Alexandria opposed voluntary desegregation, as you might expect. But the city's political leadership understood perfectly that the inevitable alternative was a series of busing orders written by a federal judge. Being sensible conservatives, they knew that the job would be done better if it was left to their own school board.

Dr. Albohm was lucky, too, in the size of the city. Scale makes a great difference in running a school system, and the ideal seems to be somewhere around Alexandria's 13,400 students. The system is big enough for good staffing and specialized instruction, but small enough that the superintendent - if he works all day and half the night, more or less continously - can stay fully in touch with his teachers and his community.

But beyond all the luck, Dr. Albohm had foresight and a strong sense of direction. The city's three high schools, for example, developed large and unfortunate disparities in curriculum because they served different kinds of neighborhood. He turned two into schools for the ninth and tenth graders, and the third - T.C. Williams High - into the citywide school for all the students in their final two years. The result is a range of vocational and academic courses that is unmatched, in its breadth and sophistication, in this metropolitan area.

There was much more at issue here than simply bringing one local school system through a turbulent decade. It has been a real question whether American public education can produce schools that people accept as good, in those communities that are not uniformly middle class suburbs. Its children are now almost evenly balanced between white and black, with substantial Asian and Hispanic minorities. There is the greatest possible mixture of economic and social conditions. The test of these schools is not over - and it won't be as long as there are children to be taught. But it's going well. Making it succeed requires, among other things, great tenacity and purpose. Those were qualities that Dr. Albohm brought with him. That, too, was part of Alexandria's good fortune.