RESEARCH TRIANGLE PARK — “When we first took this over it was very dark.”

That’s how Chris Horblit, president of Fidelity Investment’s real estate division, described the interior of one of the buildings in the Network Center, the office park that the Boston mutual fund company acquired for $34.3 million in September 2011.

Over the past 15 months the company has spent millions renovating the properties, with the goal of creating a more flexible and collaborative office environment with no shortage of natural light. With much of the work now complete, Fidelity offered the media a tour of its new space on Wednesday.

The project is an important one for Research Triangle Park, in large part because it provides another example of how the park’s inventory of aging, single-tenant buildings can be repositioned to appeal to today’s workers. It’s also a reminder that for all the chatter about how resurgent downtowns are leading to the decline of the suburban office park, many companies still prefer a campus environment. GlaxoSmithKline has done a similar makeover of several of its buildings in RTP.

The Network Center was once the home of Nortel Networks, which filed for bankruptcy in January 2009. Fidelity had been leasing two of the four buildings in the center before its purchase.

Focus on amenities

Horblit made his comment about the previous configuration while showing off a new 30-foot by 30-foot skylight that Fidelity has installed in one of the building’s cores. Like GSK, the company has moved away from corner offices and cubicles with high walls in favor of clear sightlines and shared work spaces that are designed to encourage spontaneous collaboration among employees.

“It’s about how people work,” Horblit said. “People work differently today.”

It’s also about amenities.

Fidelity has completely overhauled the Network Center’s cafeteria, installed a health and wellness center and is building an 8,000-square-foot fitness center. There’s a coffee bar and a “guru bar” where employees can have all their technology needs taken care of. The company is constructing a 2,200-space parking deck and trying to replace concrete patios surrounding the buildings with green space.

Broader plan for RTP

A lack of amenities is one of the main reasons that RTP is now moving ahead with its first redesign since the park was created 53 years ago. That plan calls for a more densely developed park featuring new shops, restaurants and residential areas, some of which would be close to the Network Center.

“It’s important to us,” Horblit said of the park’s redesign. “I think it can only enhance our experience here.”

But while Fidelity officials have been in close consultation with park officials about the particulars of the redesign, he said it wasn’t a major factor in the company’s decision to make such a large investment in its campus. The region’s abundance of talent, and its close proximity to many large customers in the mid-Atlantic region were key factors, Horblit said.

Fidelity’s North Carolina presence has grown from 450 employees 10 years ago to 3,100 today. The majority of those employees provide customer service and human resource services for 30 large corporate customers, helping manage their 401k plans and other benefits. About 1,500 of the company’s employees are technology workers, doing software development and other IT work.

The 650,000-square-foot Network Center will ultimately be home to between 2,200 and 2,400 of the company’s employees. Fidelity will continue to lease a building on Weston Parkway in Cary, but will depart the Danbury Hall building it now leases in the nearby Imperial Center.

Bracken: 919-829-4548