Robert Gorham has a runaway lead in the Pinnacle Race Course trainer standings, having won 15 races through the first 12 days of racing at the Detroit-area track. He has failed to win on only two days of the meet. Three trainers - Mary Anne Barron, John Rupert, and Richard Rettele - are tied for second with six wins each. Gorham, a veterinarian from Kalamazoo, Mich., spends much of his time on the highway pulling a horse trailer while racing at Pinnacle, Indiana Downs, and Arlington Park, as well as training on his indoor and outdoor tracks in Kalamazoo. All the while, he maintains his veterinary practice with his sister, Marion Gorham, at their West Main Animal Hospital. Nine of his winners have come for his major client, Henry Mast, who is retired from the greenhouse business. On Tuesday, Gorham posted a double, winning the fourth race with Tropic Rose ($8.40) for his sister and the seventh with Mast's Skyline Star ($3.80). Jeffrey Skerrett, Gorham's principal rider, was aboard both winners.