NEW LEBANON, New York ¿ Taller than the trees and built to last ages, the Shakers' stone barn towered over the rolling fields east of the Hudson River and symbolised the religious group's tireless industry.

Lately, the 19th-century barn has been in decay.

A suspicious fire in 1972 gutted the barn and left the 62-foot high stone walls open to the sky.

Enter the student preservationists.

The Shaker Museum and Library here is hosting a half-dozen college students in hopes of figuring out how best to save the barn. Under careful guidance, they chisel out old mortar chip by chip, trowel in new stuff and figure out how to refortify the stone walls that were first laid in 1859. "Some of it's crumbling," said student volunteer Tracy Chim, looking down at the barn walls. "And you can see the bow in the wall, and all the vegetation sucking out the nutrients in the mortar." She pointed to the empty spaces where wooden joists once held up floors rs crowded with 60 or more cows, hay, grain, wagons and Shakers tending to their tasks.

"Just looking at those and trying to imagine what it was like ... trying to recreate in your mind, trying to imagine, what it was like back in their day."

The barn was built from local stone by the Shakers, the communal religious group that had its heyday in the 19th century. The barn's dairy operation sustained the Shakers who settled what was then known as Mount Lebanon, one of many Shaker sites in upstate New York and New England.

At the height of the community, 600 residents lived in this town 170 miles north of New York City. Celibate and hardworking, they called themselves members of the United Society of Believers in Christ's Second Appearing. But the name that stuck was "Shaker," an irreverent allusion to their ecstatic dancing.

Shakers are best known today for ladder back chairs, cabinets and craft pieces that combine uncluttered lines and utilitarian design. The barn displays the same philosophy. Built into a slope, the barn had an entrance on the third floor where wagons could roll in and stock the hay loft on the second floor. Chutes sent hay down to the cows on the first floor. Manure was collected in little rail cars and dumped into the cellar, which was ground level on the low end of the slope. "This is an industrial facility. This is not some Mom-and-Pop barn. This was meant to be a huge milk processing plant," said Brian Scott Robinson, a professor of historic preservation at the Savannah College of Art and Design in Georgia.

The Shakers were known to create showpiece buildings that caught the eye of outsiders, who might then become converts. Robinson likened this barn to a Shaker version of a cathedral. Rows of windows let light pour in. Green flecks of soapstone in the aggregate fill in spaces between large stones.

"You have to think they thought, 'Well, we can't build a huge church, but we can build the biggest barn you've ever seen,"' Robinson said. It is believed to be the biggest barn of its kind during the period. With their numbers dwindling, the last Shakers left the village in 1947. The property was sold. After the fire destroyed the roof, which had kept moisture out, the remaining walls went through what site museum research director Jerry Grant calls a period of "rapid deterioration." A school, the barn's then owner, brought in steel girders to keep the south wall from collapsing.

In 2004, the not-for-profit World Monument Fund included the barn in its biennial watch list of 100 endangered historic sites, along with the Great Wall of China and Ernest Shackleton's expedition hut in Antarctica. The entire village, which has about 40 other structures, made the list two years later.

Saving the barn's walls is priority No. 1 for the museum. The students, who are guided by building experts, will mortar and seal a top corner of the barn. That work will serve as a template for a construction crew to shore up the entire barn.

It is hoped the students will seed the next generation of crafts people who can preserve and restore endangered historic structures. WMF president Bonnie Burnham said masonry and carpentry skills aren't being passed through generations as they used to be, causing a shortage of people who can perform restorative crafts.

"People are being trained to handle different kinds of materials (such as) steel I-beams and concrete slabs," Burnham said. "And there's not much opportunity for them to receive training in the traditional craft techniques."

The full-blown masonry project on the entire barn could start within a year, but the museum doesn't have a time estimate for its completion. Grant said the museum already has three-quarters of the $2 million the job is expected to cost. The site is off the WMF's watch list now, thanks to the current restorative work. The Shaker Museum and Library had at one time planned to house a museum within the stone walls. It nixed that idea because construction would have been too complex and costly. The museum is now considering a range of options that include preserving it as a ruin or restoring the building to the condition of its glory years.

"Somewhere in between, we'll settle on a plan," Grant said.