The owners of the historic Portland Company property on Fore Street have filed an application with the city to rezone the parcel, taking the first step in redeveloping a prime piece of real estate on the city’s eastern waterfront.

The 10-acre Portland Company complex, located at 58 Fore Street just east of the Ocean Gateway terminal, has housed a locomotive foundry, shipyard and steel fabrication facility during its nearly 140 years. The complex’s historic buildings are now filled with a mix of businesses and nonprofits.

The property soon could be entering the next phase in its life, mirroring the transformation happening elsewhere on the peninsula.

Since purchasing the property a year ago, representatives of the CPB2 company have begun exploring options for a mixed-use development on a site with significant commercial and residential appeal. The property has more than 1,000 feet of deep-water ocean frontage and is situated at the base of Munjoy Hill, one of Portland’s hottest real estate markets. It is within walking distance of the Old Port.

Casey Prentice, a CPB2 principal, called the site “the last frontier for downtown Portland.”

“It is a big piece of downtown,” said Prentice, who partnered with developer Jim Brady of Yarmouth and others to purchase the property. “It is waterfront and it is beautiful.”

The city’s Planning and Urban Development Department was expected to accept CPB2’s application on Friday to change the Portland Company site from a special industrial zone to a mixed-use zone. The application will be reviewed by the Planning Board. A decision is not expected for several months.

The rezoning application will be posted on the department’s website, but city officials were processing the documents Friday and had not posted it by Friday evening.

Jeff Levine, the city’s planning director, called the Portland Company property “an enormously important parcel” that could help transform that part of the city. But Levine said the development project will have to be reviewed carefully given its historic significance and longtime industrial use.

“It’s really an exciting opportunity for the city and we need to get it right,” Levine said. “So we will be carefully looking at this proposal.”

Founded in the 1840s, the Portland Company built steam locomotives for the Atlantic & St. Lawrence Railroad. Over more than a century, the company built more than 600 locomotives, 160 ships, railroad cars, marine engines, elevators, textile mill equipment and other heavy machinery.

The current Eastern Waterfront Special Use zone does not allow residential development. Prentice said that while the company is still developing specific plans for the site, he envisions a mix of residential, retail and office space at the site while maintaining the current marina used by recreational boaters.

“The best way you can describe it is if you can grab the Old Port and just stretch it and pull it over our project,” Prentice said. “We really want it to look and feel like the Old Port.”

Phinneas Sprague Jr., the property’s former owner, said he “vetted” potential buyers to make sure they understood the city’s long-range plan for the site calls for a mix of uses.

The buyers “are local guys and I have great respect for them,” Sprague said Friday. “They understand.”

Sprague turned away offers from buyers who didn’t respect the vision, including one who proposed tearing down one of the historic buildings and replacing it with a rugby field.

“I told them they should run, not walk” away from bidding on the property, Sprague said. He also has a desire to see the buildings preserved because they are part of his family’s history, as well as the city’s.

Hilary Bassett, the executive director of Greater Portland Landmarks, said Friday her organization is most concerned with preserving the 14 historic buildings, which were built between 1845 and 1950. The Portland Company complex was included on the Landmarks’ inaugural “Places in Peril” list in 2012, Bassett said, highlighting the importance of preserving it.

“It’s the only remaining intact industrial site in the city,” she said.

She and her staff have met informally with the developers, but there are no detailed plans on what the development might look like and how many buildings, if any, would be preserved and redeveloped, she said.

The proposed redevelopment of the Fore Street complex is the latest in a string of major projects reshaping Portland’s downtown waterfront. In addition to new luxury housing complexes and bustling restaurants, the area also is seeing a revival of industrial, “working waterfront” uses.

Commuter and tourist ferries, including the revived Portland-to-Nova Scotia ferry service, bring thousands of people to the waterfront terminal. Farther south on Commercial Street, the state and city are planning a massive expansion of the International Marine Terminal that connects Portland to commercial ports in Europe. And Sprague is moving forward with plans for a larger boat and yacht repair facility.

But the Portland Company site has been long viewed as prime for redevelopment.

A 2002 Eastern Waterfront Master Plan pointed out that the site was the only private property in the study area with direct access to the water. The study calls for encouraging long-term maritime uses in the area, increasing connections between the site and the developed waterfront areas, and encouraging “the adaptive reuse and sensitive rehabilitation of historic structures” on the site.

The buildings are not included in the National Register of Historic Places, but are eligible to be listed. Prentice, who owns the Chebeague Island Inn, said the buildings are a part of the history of the site and the city. Brady, another partner at CPB2, is currently converting the former Portland Press Herald building on Congress Street into a boutique hotel.

“We are excited about looking at ways to incorporate them into the plan,” Prentice said of the Portland Company buildings. “We do intend to keep that history alive.”

Kevin Miller can be contacted at 791-6312 or at:

kmiller@pressherald.com

Twitter: KevinMillerPPH