John Brockway Huntington, retired attorney, philanthropist and descendant of one of California's pioneering railroad families, died of cancer in October 1996 at his Tiburon home. He was 59. Born Feb. 28, 1937, in Bristol, England, Mr. Huntington grew up in San Francisco. He attended the Town School, the Thacher School in Ojai and the University of California at Berkeley. Later, after working as a radio announcer and a stockbroker, he attended Hastings College of the Law. Mr. Huntington worked as a deputy district attorney for Alameda County and subsequently in private practice. A descendant of pioneer railroaders Collis P. Huntington and Henry E. Huntington, he was a member of the Pacific Union Club, Bohemian Club and University Club.Mr. Huntington served on the California Arts Commission from 1974 to 1976. He was survived by daughters Marian Schinske of Point Reyes and Elizabeth Dorward and Julie De Polo of Portland; a grandson, Robert Dorward of Portland; a sister, Ann Davis of Newport Beach; and a fiancee, Ann Jackson of Portland.