All Triple Crown races are restricted to 3 year olds only.
Possibly
No horse has ever won the Triple Crown twice because they can only race in the Triple Crown races as three year olds.
It's for 3 years old horses
They are 3 years old. All horses are officially a year older every January 1st. So, regardless of the date of their birth, the Triple Crown races are for 3 year olds.
This can't be answered unless you give a list of horses.
Belmont Racetrack is a mile and a half long; the horses race a complete circuit around it to make the Belmont Stakes the longest race in the Triple Crown.
Rolled oats, corn, triple crown
He out rode all the other horses.
Not the US Triple Crown. But he did win the UK Triple Crown.
A triple crown winner is one who wins the batting average title, the runs batted in title and the home run title all in one season. The last triple crown winner was Carl Yastrzemski in 1967. A Triple play occurs in baseball when a team records three outs on a single play. The last triple play was Troy Tulowitzki's unassisted triple play on April 29, 2007. Pitchers also have a triple crown. A triple crown pitching winner leads the league in wins, strikeouts, and ERA.
Because the Kentucky Derby is for horses classified as three years old. This means they can only run once, when they are three years old.