Well done, DoubleRBar and jmd! Athlete A is Charles Kilpatrick and athlete B is Jack Keller.
Charles Kilpatrick was the leading half-miler of his time and won three consecutive US championships at the 880 yards (1894-96). He set his world record at a dual meet between the New York and London Athletic Clubs, not nearly as modest a meeting as that description might indicate - many of the world's greatest stars at the time took part, and the quality was easily higher than at the Olympics half a year later.
Jack Keller ran world records at both the 110m/120y hurdles and the 220y hurdles and won his event at the US Olympic Trials/Championships in 1932, but at the Olympics he only placed 4th, narrowly losing the bronze to Great Britain's Don Finlay. Longevity-wise, Finlay was the Allen Johnson of his times, still placing 4th at the 1950 British Empire Games; George Saling, the gold medalist, never got any such opportunity, as he died in a car accident less than a year after his Olympic victory.