Jimmy Richardson, a well-known trainer on the Maryland circuit for nearly 40 years, died after he collapsed from an apparent heart attack at Pimlico yesterday.
Richardson, 62, was atop a pony leading a horse to the post for the fifth race, when he suddenly fell from his mount near the finish line.
Rescue workers tried to revive him, but he died after being taken to Sinai Hospital.
Richardson, his wife, Sally, and five children have all at various times been involved in Maryland racing in a number of capacities.
Richardson doesn't normally pony horses, but a family friend said he was filling in for one of his daughters, who had taken the day off to go to a horse show in Columbia.