Harry Ashby DeButts, 87, retired president and board chairman of the Southern Railway Co., died yesterday at his home in Upperville, Va. Death was attributed to heart disease.

During his tenure as the chief executive of the then-Washington-based railroad, DeButts oversaw the Southern's conversion from a steam to an all-diesel railroad. He said that the replacement of steam locomotives meant great savings and faster service.

The Southern, long one of the nation's principal railroads, with thousands of miles of track stretching through 13 states, had its headquarters in Washington for 97 years, and was for many years the largest corporation in the city. The railroad is now part of the Norfolk Southern Corp. and its headquarters functions are being dispersed to Atlanta, Norfolk and Roanoke.

Mr. DeButts was born in Delaplane, Va., where his grandfather served for a time as a station agent, and Mr. DeButts acquired an early desire to enter railroading himself.

However, he confided to interviewers that he could not recall ever wishing to become a locomotive engineer. "When I was young I think I wanted to be a conductor more than anything else."

He studied civil engineering at the Virginia Military Institute and after graduation joined the Southern in 1916 as a student track apprentice at Culpeper, Va., where his tools were a pick and shovel and his salary was $43 a month.

Except for a year of service in the Marine Corps from June 1918 to June 1919 (he was discharged as a lieutenant), Mr. DeButts spent his entire working career with the Southern. In 1937 he became vice president in charge of operations and in 1952 he became president.

When asked on one occasion for advice to young persons desiring railroad careers he said:

"Be a leader. Learn how to handle people. You must have men like to work for and with you."

Mr. DeButts became chairman of the board on Feb. 1, 1962, and retired as chairman in November 1962.

He was active in the Washington business community and had also been a director of the Riggs National Bank and Woodward & Lothrop Inc.

Survivors include his wife, Mary Moore Howe DeButts of the home in Upperville; a daughter Mrs. Van Meter DeButts Page of Austin, Tex.; two brothers, Dr. Richard E. DeButts and William Hunter DeButts, both of Upperville, and two grandchildren.