Maryland's race track strike grinds into its second month, threatening the Preakness, the state's $200 million racing industry and a lot of people's patience.

Huge vans rumble through the Pimlico stables and pick up their valuable cargo for transport to other tracks in other states: a symbol of a loss that extends far beyond closed parimutuel windows.

The losers are the 550 strikers and several hundred other track employees who have been out of work for a month, about 1,350 owners and trainers whose expenses continued after the winings stopped, politicians whose mediation efforts resulted in highly publicized failure and taxpayers of Maryland, who are losing an estimated $60,000 in revenue every day a horse race isn't run.

The only winners thus far seem to be the van operators.

The 550 members of Local 692 of the Retail Store Employees Union who serve as mutuel clerks, parking attendants, starting gate crews, admission and security employees and jockeys' valets at Bowie, Laurel and Pimlico race courses struck the three tracks March 12, demanding increased health and welfare benefits.

The tracks run consecutively and most workers move from course to course as the season progresses. Bowie was just winding up and Pimlico was due to start March 21, with the Preakness, which may be moved to New York if the strike isn't settled soon, scheduled May 21.

Now, from before dawn to late morning, the track world goes on much as usual at Pimlico: exercising grooming feeding the roughly 800 throughbreds stabled here. Horses are put through their paces but there are no fans,no races, no bets. Shortly before noon activity stops, just when the action used to begin. "It's like getting dressed for church and never going," said a young exercise girl the other morning.

But the seeds of the strike go back long before March. For example:

The race track industry generally has fallen on hard times in competing for people's entertainment dollars.

Strikes have become more common; Maryland's tracks were struck briefly two years ago and a New Jersey harness track is now closed by a strike. With charges and racing days regulated by the state, the tracks cannot raise prices as other industries do, even if competition permits.

Sander Wise, attorney for the three Maryland tracks, has estimated Bowie and Laurel would be in red ink after three years if the union's demands were met.

Racing in Maryland has gradually come to be a year-round activity but workers' compensation is still geared to temporary, or seasonal, work.

When he started working at the tracks in 1953, cashier Edward Gemmill recalled as he walked the picket line in front of Pimlico Tuesday, there were only 100 racing days a year "so nearly everyone had a second job." Usually, employees had pensions or insurance coverage from other jobs.

The number of racing days has more than tripled since and racing is now available year-round except Sundays, attracting as workers younger people with families and a need for the kind of fringe benefits that normal full-time jobs provide.

The union complains the tracks don't provide benefits that are taken for granted in other jobs, such as full health insurance, overtime for a sixth day of weekly work and paid holidays and vacations. Track officials reply that the workers themselves used to demand everything in wages, thus neglecting other benefits. "Now they want to retify everything in one year," complains Al Karwacki, Bowie general manager.

The workers succumbed to a threat of strikebreakers during their 1975 walkout and appear determined to avoid another capitulation. They had an independent union then but trailed it for the retail union then but traded it for the retail union last year. Track officials blame local president Akman for this year's strike but the membership voted 455-40 Monday night to back up his rejection of the tracks' offer of a $6,50 an hour raise.

"We won't be split . . . this time," said Albert Green as he and four other workers picketed the entrance of Pimlico, carrying signs reading "Horses can live on hay; we can't."

As both sides laid their woes before the State Racing Commission earlier this week, the union was seeking a daily package increase of $9.73 (down from $12.50) while the tracks were offering $6.50, both covering three years.

Akman complained that the tracks' offer means no money would be left to keep wages abreast of cost of living increases if an adequate benefits program were to be set up. The current median wage for about 5 1/2 hours a day is estimated at $34 by the union and $36 to $37 by track attorney Wise. The union claims New York and New Jersey tracks pay more.

At Pimlico this week, trainer John DiNatala was supervising the exercising of his horses, wondering how he'll make up the $1,500 in shipping fees he paid to get his animals to other states last month.

"I can't help thinking this'll do irreparable harm to racing in Maryland," said DiNatale. "Myself, I'm ready to go to Delaware or Pennsylvania."