Tom O'Brien was a horse racing enthusiast. The horse racing world mourn his death at his passing at 39 after a cancer battle. Many publications called him a great person. O'Brien won races at the renowned racing event. The Guardian and 7NEWS reported his death after a courageous battle with cancer. At Bangor, a colleague called him a champion and a skilled jockey. Yahoo News Australia said O'Brien was the another rider to die in two days. Tributes continue across horse racing.