The historic Mortonville Bridge, a stone-arch structure that spans the west branch of the Brandywine Creek in Chester County, is one of those charming country quirks that can catch motorists by surprise.

A winding Strasburg Road leads up to it. It's raised in the middle so a driver can't really see what's coming from the other side. There's a nasty curve at the western end. And it's narrow as all get out - barely wide enough for two cars.

So when PennDot engineers came along with a plan to move it, widen it, and deliver a bridge more 21st century than 19th century, they expected folks would be pleased.

They were wrong.

"It's a gorgeous historic bridge," said Dee Durham, executive director of a local advocacy group called S.A.V.E., which stands for Safety, Agriculture, Villages, Environment. "We didn't want to see it lost."

But it is also a bridge that in PennDot's estimation is derelict - structurally deficient and functionally obsolete. Nevertheless, PennDot - lobbied by S.A.V.E. and the East Fallowfield Historic Commission - has relented and will rehabilitate, not replace, the bridge built in 1826.

It is one of the bridges on Gov. Rendell's list of 1,145 that need immediate repair.

On Thursday, Rendell said he was seeking legislative approval to borrow $600 million to fix them.

As PennDot gears up to fix the 91 bridges on his list that are in the five-county area, the story of Mortonville Bridge is one that area bridge lovers should heed, said Paula Coyne, chairman of the East Fallowfield Historic Commission.

"Every group that lives near an historic bridge needs to get together and talk to PennDot," she said. "If there are no advocacy groups, the bridges will fall through the cracks."

Chuck Davies, assistant district executive for design for PennDot's Region 6, said that some bridges lend themselves more to restoration than others, but having a group of concerned residents will draw the agency's attention.

Several years ago PennDot recognized that the number of stone-arch bridges in the region were historical treasures to be preserved, if it all possible.

In 2001, it launched Project Keystone to evaluate all 126 stone-arch bridges in the five-county region. The project's final management plan was adopted last month.

"It listed them, catalogued them, photographed them, and ranked them," said Davies. "Some were ranked highly as signature examples of their kind."

The plan has recommendations for the bridges that are worth retaining, but the agency's survey showed that others had deteriorated beyond the point of salvation, he said. The Mortonville Bridge was worth saving, PennDot concluded.

Initially, PennDot proposed building a new four-lane, 30-foot-wide span 200 feet downstream. The old bridge was put up for adoption but there were no takers. It was destined to slowly crumble into the stream, a prospect that appalled the area bridge lovers.

A new bridge would have destroyed the historic character of the village of Mortonville and scenic Strasburg Road, said Coyne.

Under the rehabilitation plans, the bridge's deck will be widened to 20 feet, the stone arches will be repaired, and as much of the original stone as possible will be used in the facing.

"I think they have come up with a really elegant solution," said Coyne. "It's really exciting they have made the commitment. It's the new PennDot."