When I was a fledgling horseplayer, I often dreamed about discovering the Secret of Beating the Races -- the system or the great truth that would enable me to win at the track.

I would learn, of course, that there is no such big "secret." Modern-day horseplayers know all of the major factors that influence the outcome of races. The best we can hope to find are little secrets or insights: We might see a horse get into trouble that most other observers missed; we might detect a subtle bias in a racing surface; we might note that a particular trainer wins often with a particular pattern.

Like prospectors mining for gold, we sift through a great mass of material in quest of an occasional nugget.

On Monday morning, while sitting at my computer terminal, I found such a nugget.

On Monday afternoon, my discovery was worth $195,070.50 -- the value of the one winning ticket on the double triple at Laurel.

While the jackpot had been growing, the third and fifth races that comprise the double triple had often been so inscrutable -- filled with bad maidens and first-time starters -- that they weren't even worth serious study.

Monday's card looked similar on the surface, but the third race was populated by so many horrible horses that there seemed to be only three in the field who could move in a forward direction. The first half of the double triple appeared likely to produce an obvious short-priced result.

So I started studying the fifth race harder, and researched the first-time starters. One of them was an obscurely bred animal named Lanahan, whose workouts were all nondescript. But when I summoned the record of his trainer, Marvin Kuhn, I stared at my computer with disbelief.

Since 1984, the computer informed me, Kuhn had saddled a total of 23 first-time starters. Seven of them -- a remarkable 30 percent -- had won. Anybody who had bet on each would have quintupled his investment.

Until the advent of the Handicappers' Data Base, a computerized information service with headquarters in Lexington, Ky., such information would have been almost impossible to find. I used to analyze trainers' methods by sitting at my desk with a stack of index cards and piles of old, yellowing racing forms.

Now every conceivable bit of data is available on computer. I may be accused of personal bias, because the Handicappers' Data Base includes my own speed figures as part of its product, but the service makes available more information than horseplayers of the past could have dreamed of.

To learn more about Kuhn's first-time starter, I called up the record of Lanahan's dam, a mare named Lady Pippin, to my computer screen, and found that eight of her previous offspring had won races, albeit cheap ones.

In 1985, her daughter, Fair Isis, won as a first-time starter at Laurel at odds of 10 to 1. The trainer: Marvin Kuhn. In 1987, her son, Sir Jace, won as a first-time starter at Laurel at 9 to 1. The trainer: Marvin Kuhn. Now I was excited.

When I went to Laurel's Sports Palace to watch the films of the horses' previous races, I gained more insights into the tough second half of the double triple. Two of the contenders, A Call To Rise and Runaway Willie, obviously had been running well, but a horse named Big A.J. could only be appreciated by a scrutiny of these films.

In his only previous start, he had come out of the gate three lengths behind the field and was accelerating into contention until he was blocked by another horse and stopped cold. The trouble he encountered hadn't been visible on the camera shot that the public normally sees, only in the head-on views.

In contrast, the other horses in Monday's fifth race who looked as if they had run decently had done so with the aid of easy, ground-saving trips. I saw only four contenders in the field: A Call To Rise, Runaway Willie, Big A.J. and first-time starter Lanahan.

This was no mortal lock, but the situation merited a healthy shot in the double triple (a bet that requires the correct order of win-place-show in the third and fifth races). I invested $1,296, playing the obvious favorites in the third race and hoping to wind up with 24 live tickets for the second half. Which is what happened.

The only horses who looked like they could move in a forward direction finished 1-2-3 in the third race, producing a short-priced payoff. I was in a position to take the shot I wanted.

I am not superstitious, but for the fifth race I sat in front of a television in the corner of the Sports Palace where I had rooted home a $134,682 double-triple payoff in April.

I cursed when Albert Delgado came out of the gate last -- as is his custom -- on the speedster A Call To Rise. I groaned when I saw that the favorite, Runaway Willie, was going nowhere. I searched the television screen in vain for any sign of Lanahan.

In midstretch, Delgado steered his horse through traffic to take a commanding lead and Big A.J. was rallying to be a clear second. They crossed the wire that way, and then the television camera quickly panned back to a mass of horseflesh vying for third place. Five horses were abreast, but I thought I saw the distinct black silks worn by Lanahan's jockey narrowly in front of that pack.

When the photo-finish was developed and the number of the 42-1 first-time starter appeared on the result board, I didn't even have to speculate whether I would have to split the $195,070.50 pool with anybody else. On this day, I was sure, I was the only person at the track who had unearthed the nugget of information that was the key to the double triple.