When her husband took a job in Cranberry several months ago, Moira Sullivan assumed the family would find a place to live nearby.

But then she and her husband, from the Philadelphia area, fell in love with Pittsburgh's 21 miles of leafy and tranquil riverfront trails. They chose an apartment in the Heinz Lofts on the North Side, and almost every day, Ms. Sullivan runs or pushes her daughter in a stroller near the banks of the Allegheny River.

"We moved here to be able to walk everywhere," Ms. Sullivan, 28, said yesterday as she stood on the dusty trail under the 16th Street Bridge, with 1-year-old Molly squirming beside her.

It was the same spot where a man attempted to abduct a female jogger Wednesday evening, but the woman fought back, forcing her attacker to flee.

The incident was a rarity along the riverfront, according to police, and there are no reasons to doubt the security of the city's extensive riverfront trail system, which has undergone a major expansion in the last two decades.

"We love it. I always feel safe here," said Abigail McNitt, also of the Heinz Lofts, as she pushed her 3-year-old daughter in a stroller by the bridge.

Police Lt. Michael Piasecki said there were plans for extra foot and bicycle patrols along the North Side portion of the riverfront.

"This is such a rare occurrence," he said of the attack. He didn't have exact figures for incidents along the river, but they are "few and far between."

Groups of homeless people tend to gather in certain spots, such as beneath the Roberto Clemente Bridge. But they haven't caused problems.

"Usually, we'll get them out of there," Lt. Piasecki said.

In 1999, then-Mayor Tom Murphy established the Riverlife Task Force, now known as just Riverlife, to start greening the riverfronts. One of the organization's main goals is the development of Three Rivers Park, a continuous system of trails and green spaces running from the 31st Street Bridge to the West End Bridge to the Hot Metal Bridge on the South Side.

"By 2020, the park will serve as the region's single greatest asset and a landmark that will define the city for years to come," Riverlife's Web site says.

Pittsburgh's trails "are one of the things that make this the 'most livable city,' " said Nick Ceraso, program director for Friends of the Riverfront, an advocacy group based on the South Side that formed in 1992.

Mr. Ceraso said he had never heard of any other violent incidents occurring on the city's riverfront trails, but he urged people to take precautions.

"If you're going to be out there, let someone know," he said. "Or have a cell phone with you for emergencies."

Also, avoid using the trails after dark, and stick to the most crowded parts of the trail system, such as the Eliza Furnace Trail between Greenfield and Downtown.

The victim of Wednesday's attack was running under the 16th Street Bridge around 7 p.m. when a man stuck out his arm and "clotheslined" her. She told police the man grabbed her by her ponytail and tried to drag her into nearby bushes.

The woman told police she screamed and kicked to fend off the attacker and ran toward two bicyclists down the trail.

The attacker fled, but he soon came back and told the woman, "Hey, I thought you were somebody else," according to Lt. Piasecki.

He then ran away again.

The man is described as white, about 5 feet 9 with a stocky build, round face and brown, bushy hair. The woman suffered a few scratches in the attack.