Erich Zimmy, the racing administrator at Charles Town racetrack, was promoted to director of racing operations on Nov. 27. Zimmy holds a master's degree from the University of Arizona's Race Track Industry Program. . . . Mike Cronin, a veteran racing marketer on the south Florida circuit, has been hired by Gulfstream Park to be an assistant to the president for marketing. Cronin, who worked in marketing at Calder Race Course for 17 years, will serve under Gulfstream's president. Ken Dunn, the longtime president of Calder who took the job at Gulfstream a month ago.