CODY, Wyoming (Reuters) - For more than a decade, Richard Ranc has worked a summer job emptying trash cans, cleaning restrooms and performing minor repairs. The work comes with some of the most spectacular views in America, but there's always the risk of bear attack.

"I go from contrasting mountain forests to mud volcanoes to lakeside shorelines," said Ranc, a seasonal maintenance worker whose daily truck route takes him on a 110-mile (180-km) round-trip journey through the scenic splendor of Yellowstone National Park.

Ranc is one of 429 seasonal employees of the National Park Service who join more than 3,200 workers hired by private concession operators each summer to perform unheralded, behind-the-scenes duties that keep Yellowstone running.

These includes waiting tables, fixing flat tires, making beds, filling pot holes and, in Ranc's case, repairing sections of the 15 miles of boardwalk that wind through Yellowstone's geysers, bubbling mud pots and hot springs.

By mid-July, Ranc and others in his department are focused on trash.

Each of the 2,000 bear-proof trash cans at every picnic table, trailhead and vault toilet must be emptied daily to prevent waste food from attracting grizzly bears.

Two Yellowstone backcountry hikers were fatally mauled last summer in separate incidents involving the same grizzly, and Ranc said he has had a number of "close encounters" with bears. About 150 bears inhabit Yellowstone, which spans parts of Wyoming, Idaho and Montana, and about 600 more roam the surrounding region.

Bears are not the only hazards for Baum's crew. Most of the park's roads - closed to cars and trucks in winter - lie above 6,500 feet in elevation, including three mountain passes higher than 8,200 feet. Baum's crew also helps plow the Beartooth Highway in Montana, just outside Yellowstone's northern boundary, which reaches 10,947 feet.

Jim Evanoff, who recently retired as Yellowstone's environmental protection specialist, said the three-month spring snow-plowing effort is the most complex operation in the park, requiring $1 million from Yellowstone's annual $69.5 million budget. A fleet of trucks, heavy equipment and rotary plows burn 1,300 gallons of diesel daily.

Each driver of the temperamental, hulking plow rigs is accompanied by two mechanics, and crews live together around the clock for weeks at a stretch, Baum said.

Then there's the matter of steering a 37-year-old plow with spinning blades around a blind curve at 9,000 feet while pushing through 20 feet of snow atop several inches of ice.

"It's not for everyone," Baum said. "It takes a certain breed. You have to be a little crazy to do it."

HUNGRY AS BEARS

Yellowstone attracts 3.5 million visitors every year, 800,000 in August alone.

For restaurant workers at Xanterra Parks and Resorts, the primary concessions contractor in Yellowstone, it sometimes seems like all 800,000 are amassed for lunch at restaurants near the Old Faithful geyser at the same time.

Old Faithful predictably erupts about every 90 minutes, so crowds either rush to finish meals before the next eruption or wait for the geyser to blow before dashing off to eat.

Everyone from fry cooks to cashiers closely tracks Old Faithful, and when it blows, they are advised to "man their battle stations," said Lu Harlow, Xanterra's director of food and beverage operations.

The two largest dining rooms near Old Faithful typically serve a combined 4,000 meals on a busy day, and Xanterra dishes up almost 2 million meals each year. Guests chew through 70,000 pounds of prime rib, 1,700 pounds of goat cheese and 4,536 gallons of huckleberry ice cream.

In winter, every bite of fresh food served at the Old Faithful Snow Lodge must be ferried in by snowmobile or snow coach.

Most Yellowstone hotels are closed in the winter, but workers keep busy clearing snow from roofs and tending to the reduced number of visitors -- and entertaining themselves.

Berg worked as a winter keeper for five years in the 1970s.

"It was fun. We wore ski boots everywhere we went and we would get together after hours," he said. "You could measure the worth of the party by the number of skis stuck in the snow outside."

When plow crews clear the roads each spring, the winter workers are able to drive into neighboring towns for the first time in months, Baum said.

That's also when the focus returns to trash, Evanoff said.

With no winter truck traffic, every bit of refuse from November to April — from plate scrapings to gum wrappers — is stored in large semi-trailers, he said.

"The second the roads are plowed open, those trailers are hooked up and gotten out of there," Evanoff said. "Semis full of raw garbage and bears coming out of hibernation at the same time — it's a strange deal."