No one was hurt, and the racing schedule wasn't disrupted.
But electrical problems shut down air conditioners and some concession stands. Officials closed the grandstand rather than have spectators broil in the heat.
Fans were given free parking and admission to the clubhouse, where the air conditioners were working.
Officials say the grandstand will remain closed Sunday, the last day of the summer meet at Belmont. Repairs will be done after racing shifts to Saratoga.
