The MBTA’s Fiscal and Management Control Board on Monday approved a $4 million contract for work to design a second commuter rail platform at Worcester’s Union Station.

The addition of a second platform would allow the MBTA to expand capacity on the Worcester commuter rail line, which is already the second busiest line in the commuter rail system. Worcester is also redeveloping part of the city near Union Station, which will include a new stadium for the Worcester Red Sox.

“With the current single-sided platform configuration, only one commuter rail train can enter the station at a time,” MBTA Assistant General Manager for Capital Delivery Beth Larkin said. “That provides limitations for what can be done and how that area can be served.”

The MBTA said 1,475 passengers board a commuter train at Worcester’s Union Station every weekday and an average of 16,293 riders use the Worcester line each weekday. Only the Providence/Stoughton line sees more passengers on an average weekday.

The proposed new platform would be fully handicap accessible and would provide additional passenger connections to the Union Station building, parking garages and easier access to the nearby bus terminal. Larkin said the project will also include upgrades to commuter rail tracks around the station and the reconstruction of the set of interlocked signals just outside the station.

The contract with HDR Engineering Inc. covers “design and engineering services for station improvements and associated track work for the Worcester Union Commuter Rail Station.” Larkin said the T expects the design and construction bidding processes to take 27 months and that construction of the platform will then take about two years.