Superintendent of the Schuylkill Division from 1970 to 1980, he worked his way up to the customer service and accounts department, which he managed from 1980 to 1984. He was responsible for 1,800 employees in meter reading and billing.
The culmination of his career, from 1984 to 1989, was his work as assistant to the president. He supervised executive support staff, spoke on behalf of other senior officers, and helped found Delaware Valley Grantmakers, a service organization for corporate philanthropy representatives, his family said.
Born and raised in Philadelphia, Mr. Walkup graduated from Central High School in 1943. He served in the Army in 1945 and 1946, then earned a bachelor of science degree in mechanical engineering from the University of Pennsylvania in 1950.
In 1967, he completed the utility executive program at the University of Michigan Graduate School of Business Administration.
He was on the board of directors of various local groups, including the Schuylkill Center for Environmental Education. He loved to travel, read history, take photographs, and sing.
Surviving are his wife of 32 years, the former Joan Beck; four grandchildren; a stepson Paul H. Sherwin; and nieces and nephews. A brother and stepdaughter, Elisabeth Cuevas, died earlier.
Donations may be made to the United Church of Christ at Valley Forge, or Schuylkill Center for Environmental Education, 8480 Hagys Mill Rd., Philadelphia 19128.