The MBTA has released its list of slow zones on the T, revealing for the first time exactly where its trains have to slow down and by how much.
The Orange Line has the highest percentage of track with speed restrictions — there are slow zones on 2.9 miles of its run from Forest Hills in Boston to Oak Grove in Malden, representing 13.1% of its run — while the Red Line has the most restricted track, 3.8 miles or 9.1% of its run, not counting the Mattapan trolley line.
Only the Blue Line has no slow zones, according to the data released by the MBTA Friday, with data available through the end of January. Overall, 6.5% of all tracks on the T have speed restrictions.
The restrictions vary in speed — trains can be required to limit their speed to 25 mph, 18 mph or 10 mph.
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Slow zones are put into place to give the MBTA a chance to make track repairs. They are supposed to be temporary, but often, they are not.
"It is really, really critical that the T treat this like an emergency," Jarred Johnson, executive director of TransitMatters, told NBC10 Boston Thursday.
The nonprofit's slow zone tracker, which maps delays, has showed a spike in recent weeks on the Red Line.
The release of the official data is a "good first step," Johnson told The Boston Globe on Friday.
The information is available on the MBTA's website, but the agency plans to set live an interactive dashboard that riders will be able to consult in real time next month, MBTA Director of Data Strategy David Burns told the newspaper.
"No one is actually publishing this information, definitely not in the way that we're doing it," he said. "So I think we're going to be leading the pack in that area."
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Also Friday, the MBTA released a dashboard listing how far along it is in complying with orders from the Federal Transit Administration at the end of a monthslong investigation into high-profile safety failures at the T.
The dashboard shows that 36% of the 545 action items the T developed to follow those orders have been completed.
"This public-facing dashboard will allow everyone to learn about the progress the MBTA is making to improve the safety and reliability of the system," said Transportation Secretary and CEO Gina Fiandaca in a statement. "MBTA management recognizes the important role the T plays in the daily lives of the communities served, that service is critical, and with this dashboard the MBTA will be transparent about efforts underway to address the FTA findings."
More delays are expected on the Orange Line, Red Line and Green Line as the MBTA plans track maintenance starting next month.
Green Line riders told NBC10 Boston Thursday they were frustrated with the slow zones.
"I feel like the T is pretty unreliable," Boston University student Lydia Evans said. "I normally only take it if I have to."