Developers have plans to transport parcels along the line from states of abandonment, vacancy or underuse to thriving states of redevelopment.

Multimillion-dollar commercial and residential projects have been proposed or are under construction along the 34-mile line, which passes through 15 county towns and four other municipalities, including the endpoint cities of Camden and Trenton.

In Florence, township officials are negotiating with a Pennsylvania developer to turn the long-vacant John A. Roebling's Sons Co. steel mill into a sprawling office park.

In Riverside, two developers are working out the details of a plan to build hundreds of new residential units and thousands of square feet of commercial space on a state-designated brownfield next to the River Line.

In Palmyra, another Pennsylvania developer is negotiating the terms of a plan with the borough to turn a 185-acre brownfield near the River Line's Route 73 station into a new development with 600 to 800 age-restricted housing units, big-box retailers and recreational activities.

In Cinnaminson, a large office park is under construction across the street from the future site of more than 900 homes.

In Beverly, the New Jersey American Water Co. has proposed to "bring the waterfront back to the public" with the construction of town houses, restaurants and stores.

Tony Nelessen, an urban designer with A. Nelessen Associates, a consulting firm based in Belle Mead, said that in its first year of operation, the River Line has become an "economic engine for growth" in the communities it passes through.

A Nelessen study commissioned by NJ Transit projected that 19,000 new residential units and nearly 11 million square feet of new commercial, industrial and office space would be built in River Line towns in the next five to 10 years.

James Stewart, president of J.P. Stewart Development in Medford, said the River Line has turned many of the long-struggling riverfront towns into "new transit communities" and created a link between these towns and Philadelphia and New York City.

Stewart has proposed the construction of a $45 million residential and commercial complex on the site of the crumbling McNeal Mansion in Burlington City. He said the River Line was a major reason he decided to pitch the project.

"We see the River Line as being just as important to our project as the Delaware River," Stewart said.

The developers' interest in the riverfront towns may also reflect a trend of movement into area that were once ignored. Smart-growth planning initiatives administered by the state Department of Community Affairs are pushing builders toward redevelopment in urban areas and away from the so-called "greenfields," the semirural properties undeveloped except for agricultural use.

For decades, developers looked to the open farmland in Burlington County to build large residential and commercial projects. Today, state, county and municipal officials are trying to slow the sprawl, preserve farmland and open space, and redirect development to urban areas.

Mark Remsa, director of the Burlington County Department of Economic Development and Regional Planning, said that with the current restrictions on greenfield development, the trend in the county is for developers to move toward redevelopment projects.

"The market has changed, and the (building) industry is following it," Remsa said.

Steve Durst, director of site acquisition for Goodman Properties of Jenkintown, Pa., agreed with Remsa's assessment.

"To take pristine land out of it's natural state is unpopular now," Durst said. "Reconditioning is a good use of the land."

Goodman Properties was selected last month by the Palmyra Council to transform a 185-acre brownfield in Palmyra near the River Line. The site was once home to a landfill, a drive-in movie theater and several industrial plants. Goodman's mission is to turn it into a viable area for housing, retail and recreational uses.

"The original cities along the river were located there for a reason," Durst said. "They're in good locations with infrastructure in place."

He said the River Line will only encourage more redevelopment in the area.

"(The River Line) is an extra incentive," Durst said. "It's already having a major impact. I think in 10 to 20 years, you're going to see some major redevelopment in these older towns."

Jason Kaplan, president of Kaplan Cos. of Highland Park in Middlesex County, said his company decided about three years ago to focus more on redevelopment projects around the state, although the firm still pursues greenfield developments where possible.

"I think it's time to take a harder look and redevelop in areas like Riverside, where the infrastructure is already in place," said Kaplan, whose company owns and plans to redevelop the Keystone Watch Case building in Riverside. "It's the nature of where development in the state is going now."

The following is a sampling of some of the major projects proposed or under way in towns along the River Line:

Beverly: The New Jersey-American Water Co. has proposed the construction of shops and condominiums on land it owns along the waterfront. While the company said it would not release a final design until July 4, artist renderings for "Beverly Landing" show town houses surrounded by a park, multistory buildings with stores and galleries, and an amphitheater and lighthouse jutting into the river. The project would cover a half-mile of waterfront from Manor Road to Cooper Street and from the river to Second Street.

Hoboken-based developer Frank Reia is planning to convert the former St. Joseph Roman Catholic Church convent into apartments for senior citizens.

In addition, city officials have met with a few developers interested in redeveloping part of Railroad Avenue near the light-rail stop. There is one active business and an empty acre of land at the avenue's intersection with Broad Street. The vacant lot had been the home of the Beverly Underwear Factory, which was torn down last year.

Burlington City: J.P. Stewart Development has a $45 million plan for residential and commercial development at the site of the long-vacant McNeal Mansion on Pearl Street. The proposal includes 171 town houses and condominiums, a marina, a restaurant and more than 70,000 square feet of office and retail space on the 20-acre property on the Delaware River. Twenty of the condominiums would be in the restored mansion.

Part of the plan calls for two connected three-story buildings next to the River Line tracks, with office space on the top two floors and retail space on the ground floors. Included in the project would be a new rail station, the third stop in the city. City officials are creating a redevelopment zone for the McNeal property.

The Philadelphia-based Westrum Development Co. wants to build 97 town houses along Tatham Street and 45 town houses and condominiums along the riverfront at the site of an old waterworks plant.

The Stewart and Westrum projects have received preliminary approval from the City Council.

Officials with D'Anastasio Corp., based in Pennsauken, want to build 41 town houses on the six-acre site of the former Gregory's department store at Washington Avenue and Juniper Street.

Five new businesses have opened in the city since the River Line began running, and two other business are expected to open, according to Donna Boone, executive director of the city's Main Street New Jersey program.

The city Planning Board is also considering proposals for a catering facility and banquet hall and a furniture center and distribution center in the city-owned Commerce Square.

Cinnaminson: Developer 1714 Bannard Street LLC is constructing a 105,000-square-foot business park with office, warehouse, storage and restaurant space on Bannard Street next to the River Line station, where Centron Coatings and a former pallet warehouse once stood.

The business park is across the street from the Villages at Cinnaminson Harbour, a 911-unit residential development being built by Kaplan Cos. Jason Kaplan, the company's president, said the project was conceived before his firm realized the impact of the River Line. Once the impact was realized, he said, the firm's designers went back and realigned the entrance of the development to provide better access to the light-rail line.

Delanco: J.S. Hovnanian & Sons has proposed a development of 92 town houses along Coopertown Road near the River Line and the Rancocas Creek. The developer is expected to take the plan to the township's Joint Land Use Board within the next month, township officials said.

In addition, a major moving and storage company is in preliminary negotiations with the township to move to another site off Coopertown Road. Due to ongoing negotiations, township officials declined to name the company involved.

Edgewater Park: Mayor Richard Tucker said township officials are looking to revamp the township's master plan to allow more businesses to build along the rail line and Route 130.

Tucker said township officials are considering a plan to turn the area near the River Line's Beverly/Edgewater Park stop into a "transit village" with new sidewalks, street lights, businesses and homes. The "transit village" designation would make the township eligible for special grants from the state Department of Transportation for many of the improvements.

Florence: Township officials are in negotiations with Conshohocken, Pa.-based Preferred Properties, which would build a massive office park on the site of the former John A. Roebling's Sons Co. steel mill. Detailed plans of the project have not yet been made public, but the development would likely take up a large portion of the 234-acre property, which has been on the federal Superfund list of contaminated sites since 1983.

Last year, the second phase of construction of Whitesell Construction Co.'s Haines Industrial Center began. The Delran-based construction firm plans to erect 20 warehouses totaling 6 million square feet of space at the 700-acre center near the Burlington Township border.

Palmyra: Borough officials recently selected Goodman Properties to redevelop an 185-acre brownfield near the Route 73/Pennsauken station into a site for residential, commercial and recreational uses.

Goodman's proposal calls for about 350,000 square feet of retail space with several big-box retailers and a supermarket on one section of the property. It also calls for 600 to 800 age-restricted living units.

Borough officials have expressed some concerns about the number of housing units, an issue being addressed as the town and developer hammer out a final design agreement.

Goodman's plan includes leisure and recreational uses, such as an antique carousel, a miniature-golf course, paddle boats and a narrow-gauge railroad, along with an Amish farm and market and a 10-acre petting zoo.

Riverside: The Township Committee recently selected the team of Keating Partners of Philadelphia and Pulte Homes of Trevose, Pa., to redevelop the majority of a brownfield known as the Golden Triangle, which is bordered by Pavilion Avenue, the Rancocas Creek and the River Line's tracks.

The partnership proposed the construction of hundreds of residential units and 24,000 square feet of retail space. The dwellings would include 66 town houses facing the creek and 200 condominiums in the middle of the property.

Kaplan Cos. owns the centerpiece of the Golden Triangle, the Keystone Watch Case building constructed in 1908, and an adjacent property. Kaplan is proposing to build about 200 town houses and 60 condominiums. The first floor of the seven-story Watch Case building would have some commercial office space.

The developers and township officials are working out details of the agreements.