Across the country, racing officials are worrying about dwindling attendance at their tracks.

But at Saratoga, which closed a four-week meeting today, the New York Racing Association is trying to comprehend the reasons for the track's remarkable boom in popularity and to cope with its success.

Only a few years ago, the very existence of the annual Saratoga season was unjustifiable from a business standpoint; it was an indulgence for the wealthy members of the horsey set who liked to spend August here. The attendance was about half of what it would be downstate.

Not any more. While business has dwindled at Aqueduct and Belmont, Saratoga has become a phenomenon. The average daily attendance at Belmont Park this summer was about 20,000. At Saratoga, 20,000 represents a slow day. The average crowd has been approximately 25,000. On one ordinary Wednesday, with no special attraction, 31,386 people crowded into the historic track.

Why has this all happened? NYRA officials, who are widely blamed for the sport's ills downstate, are trying to figure out what they are doing right. They credit the overall growth of this geographical area and particularly the growth in tourism, sparked by the "I Love New York" advertising campaign. The track also has the advantage of being nearly the only game in town, so it gets the kind of media coverage that every track owner dreams of.

Harvey Pack of the NYRA's, offers an additional theory: while off-track betting has siphoned away customers from Aqueduct and Belmont, it has helped Saratoga immensely. "OTB has created new horseplayers here, but they don't get to see a horse for 11 months. What would it be like if we could only go to the track one month a year? We'd start getting the shakes in May."

Whatever the causes of the Saratoga boom, their effects are visible every day. Too visible. What was once a bucolic, sedate track is now packed to the rafters. There are only 15,000 seats for all these customers. (Clubhouse reserved seats for the meeting go on sale Jan. 1 and are gone on Jan. 2). There are long lines at the mutuel windows, lines at the bathrooms, lines at the ice-cream stands. Because the facilities are so overtaxed, Saratoga needs nearly five hours to put on a nine-race card. Even for the hard-core players, a day at the races here sometimes seems interminable.

"For the first time this year, I've been getting letters from fans complaining about the service," James Heffernan, the NYRA's president, admitted. "Our facilities are too small; the seating situation is ludicrous. That's why we've been going to Albany for the last three years trying to get money for capital improvements."

The NYRA wants to be able to go into the bond market and raise $20 million to expand the facilities here, but so far the New York politicians have not given their approval. In order to cut down the daily crowds and capitalize on Saratoga's popularity, the NYRA might lengthen the season here to five weeks next summer. But if some changes are not made, Heffernan said, "we're going to be turning our fans off and see this growth stop."

It may be the first time a racetrack has suffered because it is too beautiful, charming and popular.