The dirt spread across the mile oval at Pimlico Race Course is like a blanket of sponges.
Crews arrive before dawn to compress and till the bed of loam, a mix of masonry sand, clay and silt 3 inches deep. As thoroughbreds begin their workouts at first light, the soil softens the blows of hooves before they plant on a foundation of finely crushed limestone and press forward.
When the track is fast, the soil feels bouncy, moist enough to lie in harrowed grooves but dry enough to coat your teeth in grit.
It is both a science and an art to keep it in such fine condition. This week, sun and wind have sucked moisture from the track, requiring that up to 70,000 gallons of water be sprayed on it from trucks each day. And with thunderstorms in the forecast around the 6:18 p.m. post time for Saturday's 140th Preakness Stakes, crews keep tools handy to press excess water to the surface so it can run off into the infield.
David Whitman, the track's maintenance director for the past decade, can determine whether it is fast with a glance. But that doesn't mean his job is easy — the safety of thoroughbreds and jockeys depends on track conditions.
Usually the weather is to blame when he hears criticism from trainers, he said. And he frequently gets criticism.
"To one, it's deep; to one, it's not deep enough. To one, it's too fast; to another, it's too slow," Whitman said. "You'll never please all of them. You'd better have thick skin to do this job."
While tracks across the country have moved to replace dirt with synthetic, all-weather surfaces — largely because of incidents like Barbaro's leg-shattering injury at the 2006 Preakness — the loam loop at Old Hilltop still requires nearly round-the-clock maintenance.
In good conditions, crews drive tractors pulling 5-ton rollers to compress the soil and then drag harrows — metal frames with tines like a rake — to break it up and stir it. Trucks moisten it with water sprayed from behind or from a boom extended over the inside of the track.
On a normal day, seven truckloads of water — each carrying 3,500 gallons — are sprayed across the track before racing begins at 1:10 p.m. Another 6,000 or so gallons are sprayed between races whenever possible, said Kenny Wilson, a track superintendent who is the son of Kentucky Derby-winning jockey Rick Wilson.
On a sunny, windy day, the track can require as many as 20 truckloads, Kenny Wilson said. Dirt tracks are generally kept at moisture levels between 8 percent and 12 percent, though Whitman said he doesn't closely track the precise water content of Pimlico's oval.
But when it rains, maintaining the surface gets trickier.
Crews use the heavy rollers to "seal" the track, preventing water from seeping in. And then periodically amid steady rain, they will pull what is known as a float over the surface — a lighter flat slab of metal that squeezes water to the surface.
"We float it and leave it alone," Wilson said. "Sometimes you'll make it worse."
If it's going to rain, a quick downpour is the easiest to manage, Whitman said. A day of light, soaking rain can be impossible to keep up with.
"You don't want it to turn to mush," Whitman said.
Of course, trainers are used to managing the conditions.
"I think he'll be fine," Simon Callaghan said of Firing Line, runner-up to American Pharoah in the Kentucky Derby. "I think the rain would just tighten up the track a little more. He's run very well on several different racetracks, so I don't think it will be a problem."
A wet track benefits some horses.
Mr. Z likes the mud, said D. Wayne Lukas, who has trained six Preakness winners and will saddle Mr. Z in the Preakness. "I don't think we'll get a muddy track. This track holds the water so well, and they do such a good job here. The track was deep and loose out there [Wednesday]. Really deep. I never saw it that deep as it was out there today."
Mud isn't necessarily dangerous, said Mick Peterson, a mechanical engineering professor at the University of Maine whose research focus is horse racing track surfaces. One well-known study in the 1980s showed wet tracks were safer, he said. Just as people walk gingerly and with short strides on an icy sidewalk, horses can adjust to slippery conditions.
But when racing surfaces become uneven and inconsistent, racehorses cannot see slick spots or puddles as they gallop down the home stretch, Peterson said.
A horse's main risk for injury in poor conditions is to the first of its front legs to touch the ground, as its hoof reaches out ahead of the animal's center of mass at speeds of up to 70 mph, he said.
There are not precise standards for when a track could be deemed unsafe, given the different materials and conditions at tracks, said Steve Koch, executive director of the National Thoroughbred Racing Association's Safety and Integrity Alliance.
"Maintaining a high-quality racing surface is a very artful process" that relies on track men who know their ovals well, Koch said. "He knows how his track behaves and performs under the various and changing weather conditions."
Pimlico has been lucky with weather on Preakness day, said Whitman, who has maintained tracks for the Maryland Jockey Club for nearly 31 years, previously working at Laurel Park. But even when it rains, the track holds up well.
Rain began falling about 45 minutes before the Preakness in 2007 and intensified 15 minutes before post time, but the track was nonetheless rated "fast" — optimum conditions considered dry, fast and even. In 2003, the track was rated "good", a step below fast, after heavy rain fell on Black-Eyed Susan Day, the day before the Preakness.
The last time the Preakness was run on worse track conditions was in 1983, when it was rated "sloppy" — wet on the surface but firm at the bottom. That was the last year the race was won by a Maryland-bred horse, Deputed Testamony, who died in 2012 at Bonita Farm in Harford County.
As long as rainfall is about a tenth of an inch or less Saturday, Whitman said he doesn't expect any problems. The National Weather Service is calling for hot, humid air to move into the region, fueling scattered yet potentially heavy showers and thunderstorms in the afternoon and evening.
That had Whitman checking the forecast, and knocking on wood.
"I hope it changes," he said. "We've been really lucky with that."
Baltimore Sun reporter Childs Walker contributed to this article.
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