It’s a start, they stressed. For years one of the chief criticisms of those who run Thoroughbred racing is that the sport’s major players refused to work together. Each entity was protective of its own turf, with its own procedures and set of rules. Instead of one voice to speak for and address important issues within the industry, there was a scattering of often competing jurisdictions. Tuesday at the Keeneland Library, representatives of major American tracks promised to change that.