SPRINGFIELD - Contractors at Springfield Union Station have begun driving more than 200 pressure injected footings for the project's 6-floor, 377-space parking facility at what was once the site of the Hotel Charles at Frank B. Murray and Main streets.

The foundation work is just one aspect of the station project expected to pick up momentum this summer, said Christopher J. Moskal, executive director of the the Springfield Redevelopment Authority.

Last week, the board approved $20 million worth of interior work at the station, a package of work that includes windows and other fixtures. The interior has already been stripped in preparation for rebuilding. Workers have also removed the track-side canopy roof at the station and it must be replaced.

The pedestrian tunnel leading under the train tracks to Lyman Street will also be reopened and waterproofed. From the tunnel, passengers will climb stairs or take elevators up to the platforms.

"Things are going to start gearing up," Moskal said. "This is the time when people will start to see construction."

After years of false starts, the Springfield Redevelopment Authority, with the support of U.S. Rep. Richard E. Neal,-D-Springfield, is redeveloping the former Union Station into the Union Station Regional Intermodal Transportation Center.

The $88 million project, funded with a combination of state and federal money, is expected to be completed in the fall of 2016.

Construction continues on Union Station Project 9 Gallery: Construction continues on Union Station Project

That's a tight schedule for a project that includes the parking deck, 26 berths for intercity and local intra-city buses and rail service. A 60,000-square-foot grand concourse waiting room with retail and restaurant amenities, ticketing offices for buses and trains office space and possibly a day care center.

The plan is to increase the frequency of passenger service through the station.

"All of these components have to work together to meet that schedule," Moskal said. "There is going to be a mass of activity."

The foundation tubes being installed now will be cut off and topped with the first deck and frame of the parking structure.

The Redevelopment Authority has also hired The Massachusetts Realty Group, a partnership of Greystone and JLL, to help lease the space. The Massachusetts Realty Group does a lot of work for the Massachusetts Department of Transportation including leasing at South Station in Boston.

Built in 1926, Springfield Union Station served as bustling gateway to the city for generations before closing in the 1970's.