Robert Eugene (Bob) Loomis, 57, the assistant vice president for labor relations of the Southern Railway since 1969, died of a heart attack Dec. 8 at George Washington University Hospital.

Mr. Loomis, who lived in Great Falls, Va., was born in Chicago. He graduated from the Illinois Institute of Technology and the John Marshall Law School. He was admitted to the bar in Illinois.

He began his railway career in 1951 with the United States Steel Corp. and worked for several of the lines that the corporation owns. He later worked for U.S. Steel's law department in New York and was an assistant to the president of its railroads. He continued there until 1969, when he moved to this area and joined Southern.

Mr. Loomis was a member of the American Railway Engineering Association, the University Club and the River Bend Golf and Country Club.

His survivors include his wife, the former Joyce M. Wood, whom he married in 1946, of Great Falls; three sons, Michael Eugene, of Cinnaminson, N.J., Bradley Scott, of Rochester, N.Y., and Jeffrey Dean, of Herndon; his mother, Lillian R. Loomis, and a sister, Irene Kelly, both of Oak Park, Ill., and eight grandchildren.