The Massachusetts Bay Transportation Authority, or MBTA, will begin a series of weekend shutdowns early August on its Lowell commuter-rail line to install Positive Train Control, or PTC.

Commuters wait for the Red Line in Cambridge’s busy Porter Square station in February 2015. After MBTA service was suspended, the rail service was up again but at a limited schedule. Robin Lubbock/WBUR

Progressive Railroading reports the closures will run through early October.

PTC is a GPS system that offers emergency intervention in the case of human error.

Wide shot of crash scene with emergency workers

National Transportation Safety Board’s official report blamed the 2008 Chatsworth Metrolink crash on the train engineer who was texting just seconds before impact.

In the wake of the 2008 Metrolink crash in Chatsworth,  U.S. Senator Dianne Feinstein said she believed the technology could’ve prevented the tragedy.  A total of 135 passengers were injured in the accident, and 25 more were killed. Less than a month later, Feinstein helped the U.S. Congress push through the 2008 Rail Safety Improvement Act.

At its core, the federal law requires most train companies to implement PTC.  The initial deadline was December 2015.  But after several major railroads threatened a service shutdown, Congress extended the deadline to 2018.

Since lawmakers mandate more stringent rail safety standards in 2008, the railroad industry has spent more than $260 million dollars lobbying Congress for more time.

Despite ongoing resistance by key industry players, California’s own regional commuter train –Metrolink– began implemented PTC technology on some of its Orange County lines in April 2015.  By June, the new technology had been installed on all 341 miles of right of way exclusively belonging to Metrolink.