Red Line trains speeded up as they crossed the Longfellow Bridge on Friday night for the first time since June after officials lifted a 10-mile-per-hour speed restriction that had been in place on the 102-year-old span.
Repairs on the bridge are more than 65 percent complete and have progressed to the point that state and federal officials determined that trains could again travel at full speed.
The trains will be limited to 25 miles per hour for the next few days while engineers monitor the new ties that have been installed, said Joe Pesaturo, a spokesman for the Massachusetts Bay Transportation Authority. Under normal conditions, trains typically travel 25 to 40 miles per hour on the bridge. The Red Line gets about 87,000 daily commuters.
The Federal Highway Administration had urged the state to limit the trains' speed based on concerns for the concrete below the tracks, which had not been inspected despite the intense scrutiny the rest of the bridge has received.
Officials wanted to be sure that the concrete could withstand the load when so many parts of the bridge were crumbling.
Test borings of the concrete have showed no problems, according to Richard K. Sullivan Jr., commissioner of the Massachusetts Department of Conservation and Recreation, which owns the bridge. "The analysis is done and there are no concerns," Sullivan said.
Crews were working nightly to shore up the bridge - and following federal authorities' recommendation to accelerate critical repairs nearest the Red Line tracks, rather than moving sequentially down the tracks.
"The most critical repairs all were completed," Sullivan said.
The state had its hired engineering consultants conduct another load rating on the bridge. Based on those results, state and federal authorities determined that it would be safe to let trains travel at greater speeds.
Stephanie Ebbert can be reached at firstname.lastname@example.org.