SOUTH DEERFIELD — The bridge carrying North Main Street over the railroad tracks will remain closed indefinitely, although progress is being made, as the Massachusetts Department of Transportation is in the process of reviewing construction plans.

The agency closed the bridge in late May upon the discovery of deteriorated decking, which resulted in detours on the heavily traveled street that functions as one of the main roads into South Deerfield and features both Frontier Regional School and Tilton Library.

MassDOT is currently reviewing the plans and once the agency approves them, they must be sent on to railroad operator Genesse & Wyoming, as the bridge crosses over the tracks. Once the railroad company approves the plan, the procurement process, which lasts about 90 days, can proceed and then construction can commence.

Deerfield Police Chief and Emergency Management Director John Paciorek Jr. said he is hopeful work can begin in December and finish by the end of winter, although he noted there are “many different moving parts to this.”

“This project is a full superstructure replacement; which includes the deck, girders and truss. This is one of very few DOT bridges left in the state that are wood superstructures and therefore sourcing materials tends to be more of a challenge,” Paciorek wrote in an email. “MassDOT has been nothing but amazing working with the town.”

Additionally, no town money will be used to demolish and replace the bridge, according to Paciorek. The state has yet to determine a final cost for the project and funding is planned to come from an active bridge maintenance contract.

While the road remains closed, traffic coming from South Deerfield will continue to be detoured to Hillside Road, while traffic on the northern end of the street will be detoured to Routes 5 and 10 toward North Hillside Road.

“The closure has had a tremendous impact on traffic within the community,” Paciorek said. “The town has full faith in MassDOT District Two.”

Chris Larabee can be reached at clarabee@recorder.com.