"The Big Apple" gave birth to "the Big A," and not the other way around. I spoke to the longtime secretary of the New York Racing Association, and she credited Gene Ward of the New York Daily News with coinage of "the Big A" in the 1950s. She said "the Big Apple" as the nickname for New York City's racetracks had inspired Ward's coinage. I sent several letters to the Daily News in the early 1990s, but none were returned. Gene Ward died in 1992.
The full-text New York Times should provide something close to the earliest citation of "the Big A," if not the first citation itself. The first database hit is in the 1950s, on the re-opening of a renovated Aqueduct racetrack.
Wikipedia: Aqueduct Racetrack
Aqueduct Racetrack, known as the Big A, is a horse racetrack in the neighborhood of Ozone Park in the New York City borough of Queens.
The racetrack opened in 1894 and was rebuilt in 1959, with additional renovations made in 2001 and 2006.
29 April 1959, New York (NY) Times, pg. 52:
Advertising: B.B.D.O. Sounds the "Big A"
By CARL SPIELVOGEL
Several weeks before the announcer at the Aqueduct race track sounds the familiar "the horses are on the track," a $500,000 advertising and promotion program will have started.
The campaign for the new $33,000,000 facility, near Idlewild Airport, will be handled by Batten, Barton, Durstine & Osborne, Inc. The theme of the drive will involve the use of a "Big A."
This stands for Aqueduct. It also relates to the nickname for New York City thoroughbred racing, referred to by improvers of the breed as the "Big Apple." This is meant to signify big-time racing, as opposed to racing in smaller cities.
9 September 1959, New York (NY) Times, pg. 21 ad:
the big A
Everything about the new Aqueduct is so big that it is referred to as the Big A.
New York City • The Big Apple • 1970s-present: False Etymologies • (0) Comments • Tuesday, July 13, 2004 • Permalink