Officials will limit the Belmont crowd to 90,000 for American Pharoah's Triple Crown bid to avoid a repeat of last year.

The 102,000 spectators who came to see California Chrome try to win the 2014 triple crown suffered through long lines at betting windows and bathrooms.

Concession stands ran out of refreshments. Many spent hours jockeying for space on commuter trains or in jammed parking lots going home.

The New York Racing Association has also hired a former FBI official to co-ordinate security, added more concession stands and staff, reconfigured parking lots and scheduled a post-race rock concert to slow the exodus on Saturday.

The Long Island Rail Road is also pouring $4 million to upgrade the Belmont Park station.

Christopher Kay, NYRA's chief executive officer, said complaints after last year's race "broke my heart".

"We looked at the experience last year and realised there were too many people on the property," Kay said.

The prospect of a Triple Crown winner has traditionally spiked attendance at Belmont. The record for a Belmont Stakes race was set in 2004, when 120,139 people jammed the park to see Smarty Jones' try to complete the rare Triple Crown.

American Pharoah is the favourite to become the first horse since Affirmed in 1978 to complete the Triple Crown of the Kentucky Derby, Preakness Stakes and Belmont Stakes.