MBTA completes roll in of new bridge

Two 80-wheel transporters roll the new bridge into place.

MassDOT

The Massachusetts Bay Transportation Authority (MBTA) successfully rolled a new bridge for the Fitchburg Commuter Rail Line into place on Saturday, Aug. 29.

Trains were restricted to 25 mph on the old bridge over Route 62/Main Street in Concord, which had low clearance and was in poor condition. The new bridge is two and a half feet higher over the roadway, has a wider sidewalk and allows trains to continue at the normal speed of 65 mph.

To minimize the impact of the replacement work to rail and road traffic, the MBTA used an accelerated bridge replacement process to “roll-in” the new bridge.

“Traditional construction techniques would have required the roadway to be closed for a month and rail service to be interrupted for a nine day period,” said MBTA General Manager Frank DePaola. “By using the ‘roll-in’ process, almost all of the work is taking place over the course of one weekend.”

Construction crews have been working since last year, preparing foundations for the new bridge. The new bridge structure was assembled over the roadway adjacent to the existing bridge.

Track was removed and the existing bridge demolished then the new structure, supported on two 80-wheel transporters, was slowly rolled into place. New track was then installed and the line returned to service in time for the regularly scheduled start of service the morning of Aug. 31.

The $9 million Route 62 Bridge replacement is part of the $300 million Fitchburg Line Improvement project which includes the rehabilitation of seven bridges, the installation of nine miles of new track, the construction of new accessible stations in Littleton and South Acton and the modernization of track and signals throughout the 50-mile line.

“When the work is completed at the end of this year, commuter rail service on the Fitchburg Line will be faster and more reliable,” said DePaola.