Francis Emerson Beeton Sr., 90, a retired superviser with the old Post Office Department's Railway Mail Service who had lived in Northern Virginia for the past 57 years, died of pneumonia Thursday at Northern Virginia Doctors Hospital.

Mr. Beeton was a native of Lexington, Va., and a graduate of the Virginia Military Institute. He worked in his father's business, the Lexington Steam Lanundry, and in silent movie theaters in Lexington and Richmond where he played the piano, before joining the Post Office in 1916.

For the next 42 years, he supervised mail cars attached to passenger trains that ran between Washington and Charlotte, N.C.

Mr. Beeton retired in 1958. He had been a resident of Falls Church for the past 15 years.

Survivors include his wife of 64 years, the former Anna Vetter, of Falls Church; a son, Francis E. Jr. of Fairfax; seven daughters, Pauline Ambrogi of Vienna, Helen Fines of Fairfax, Jane Bouteiller of McLean, Frances Kane of Luray, Nancy B. Fritz of Clearwater, Fla., Beth Ann Vice of Collinsville, Okla., and Kathleen B. Butler of Charlotte; a sister, Mae B. Hallman of Norristown, Pa.; three brothers, Robert D., of Bluemont, Va., Lionel, of Richmond, and Guy M., of Pleasantville, N.Y.; 32 grandchildren, and 24 great-grandchildren.

The family suggests that expressions of sympathy be that expressions of sympathy be in the form of contributions to the Francis E. Beeton Memorial Fund of the Community Methodist Church in Arlington.