Story highlights One horse threw his rider and ran into a crowd of horses going in the opposite direction

Six Drivers and Caixa Eletronica died instantly, and a rider was taken to a hospital

Caixa Eletronica, a 9-year-old, won seven stakes races and $1.8 million in his career

Routine training exercises turned deadly Saturday morning when two racehorses collided at Belmont Park in New York, killing both animals and injuring one rider, officials told CNN.

The incident occurred at a training track at Belmont at about 8 a.m.

Six Drivers, a 4-year-old colt, threw his rider and ran into a crowd of horses running in the opposite direction, New York Racing Associating spokesman Eric Wing told CNN.

Six Drivers crashed into Caixa Eletronica, a multiple-stakes-winning thoroughbred, killing both horses and injuring Caixa Eletronica's rider, Carlos Castro, who was taken to a nearby hospital for evaluation, according to a racing association press release.

"This was a freakish tragedy that happens very, very rarely, but it makes it no less unfortunate," Wing told CNN.

Caixa Eletronica suffered a skull fracture and Six Drivers a neck fracture in the incident. The racing association's chief examining veterinarian said both horses died immediately, according to the press release.

Caixa Eletronica was a prolific racer and fan favorite.

"For any horse, it's horrible. When you hear it's Caixa Eletronica, it's magnified," the horse's owner, Mike Reople, said in a press release.

Caixa Eletronica, a 9-year-old, had a record of 23 wins in 69 lifetime starts, won seven stakes and earned more than $1.8 million.

Belmont Park is the site of the Belmont Stakes, the annual final race of the Triple Crown.