With the conclusion of training hours at noon Aug. 10, Philadelphia Park closed its main track for racing and training for 14 to 16 days, weather permitting, for renovation of the surface.Philly Park director of racing Sal Sinatra said the surface has been "needing some attention" due to year-round racing demands."Starting today, we're going to be peeling off the cushion, then adding 10,000 tons of limestone," Sinatra said. "We'll be resetting the grade, because the crown has sunk six to eight inches in some areas. After the limestone is added, about an inch of clay will be put down, and then the top surface."The drainage boards along the inside rail will be replaced and all the drains will be cleaned out."Sinatra said he tried to accomodate horsemen prior to the shutdown by carding two extra races Aug. 8 and one Aug. 9, and extending training hours Aug. 10 by two hours.While the turf course isn't in line for major work, Sinatra said Billy Gatto, the turf superintendant at Atlantic City Race Course, would come to Philly Park to test and check the grass.Sinatra said the surface should be ready for Labor Day weekend. The $750,000 Pennsylvania Derby (gr. II), the track's signature event, is held on Labor Day.