For once, there are some signs of optimism in Maryland's horse racing industry, and not just about the marquee event on Saturday. The long-promised benefits of diverting some revenue from slot machine gambling into horse racing finally seem to be taking hold, with larger purses and better fields in the day-to-day races at Pimlico and Laurel Park. The betting handle is up, too, thanks in large part to the growth in online wagering. Slots money has also enabled the resurrection of the storied Pimlico Special, a $300,000 stakes race that will take place before the Preakness on Saturday. It had not been run for several years because of a lack of purse money. Some are even talking up the idea of the Preakness one day matching the Kentucky Derby's $2 million purse, but even as it is, the Preakness will have a full field this year, and both attendance and betting could approach all-time records.