THE PERCENTAGE of MBTA subway tracks with speed restrictions is heading in the wrong direction.
In March, T officials said they uncovered some unspecified breakdown in rail repair work, which prompted the acting general manager, Jeffrey Gonneville, to order a systemwide slowdown on the entire subway system to make sure the trains ran at lower speeds and stayed on the tracks.
Gonneville dispatched engineering teams to inspect tracks across the system and slowly the universal slowdown was replaced with a patchwork quilt of speed restrictions across every line – all designed to allow trains to operate safely on defective track. The percent of subway track with speed restrictions hit a peak of 27.8 percent on March 27 and then began slowly trending down through April, May, and June, hitting 22 percent on June 13.
But, since then, the percent of track with slow zone restrictions began inching up again, hitting 23.6 percent on Thursday. It’s hard to understand what’s happening, and T officials have been tight-lipped about what has gone wrong and when the slow zones will disappear.
T officials say slow zones have been slow to disappear in part because of the way they are being addressed.
“Lifting speed restrictions is a dynamic process,” said T spokeswoman Lisa Battiston. “While the percentage of restricted track will fluctuate as track defects are rectified, General Manager Phillip Eng has directed staff to target the most severe speed restrictions first in order to improve trip times for riders while also accomplishing this critical work. For example, on the Red Line, there were two speed restrictions that were recently improved from 10 mph to 25 mph – while the track is still restricted, trip times are improving.”
That explains why speed restrictions as a percent of subway track might not be declining, but it doesn’t explain why they are increasing. Battiston said some new track defects have been discovered, particularly in the wake of a derailment on the Green Line’s B branch.
The Lechmere Viaduct on the Green Line, across from the Science Museum, may also provide some clues about slow zones. In 2021, as part of an overhaul related to the Green Line extension, the T made extensive repairs to the viaduct. An MBTA tweet on July 16, 2021, also referenced “new tracks on Lechmere Viaduct.”
Fast-forward to June this year and the T, according to agency tweets, began laying 2,700 feet of new track “to lift speed restrictions and enhance safety.” Another tweet in late June said the T “replaced, welded & aligned 3,300+ feet of rail to improve conditions, which will allow us to increase speeds in this area.”
The tweets from 2023 make it sound as if the T was completing work on the viaduct that probably should have been done in 2021. Battiston, in a series of emails, said the work in 2021 was primarily structural and not speed related. She said many of the rail ties were replaced in 2021 but the rail itself was reused.
“When the work was being done in 2021, the rail still had useful life, so it wasn’t fiscally responsible to replace it at the time,” she said.
“The primary objective of the 2021 Lechmere project was to strengthen the structure in order to remove the operational speed restriction that only allowed one train to cross at a time,” she said. “Now there are three condition-based speed restrictions that are planned to be addressed with the replacement of specially formed ties.”
Battiston said two of the speed restrictions were put in place on the viaduct in December 2021 and a third was added in June 2023. Those slow zones are now being addressed, which should reduce the percent of subway track subject to speed restrictions as long as new defects don’t emerge in the meantime.