A computer system designed to prevent train crashes is still two years out from being installed on Boston’s commuter rail lines, even though a federal deadline looms next year.
The MBTA has told the federal Department of Transportation it expects to have the system, called "positive train control," completed on all its lines by 2020.
Investigators in Washington State said the deadly Amtrak train crash Monday about 45 miles southwest of Seattle did not have its positive train control system active. The cause of the derailment is still under investigation and it is unknown whether the system could have prevented the crash.
The NBC Boston Investigators started asking about positive train control last year after deadly train crashes in Philadelphia and Hoboken, New Jersey.
The system is designed to slow or stop a train if comes too close to another train or approaches a station too fast.
"It’s important because sometimes we don’t know if there’s a switch that’s properly set, the operator may not realize how fast he or she is going, the operator could become incapacitated," said Bill Messner, a mechanical engineering professor at Tufts University who specializes in automatic control systems.
A decade ago, the federal government required all railroads to install PTC by 2015. Congress bumped that deadline to 2018.
Only 10 percent of MBTA tracks are outfitted for the safety system, according to the U.S. Department of Transportation. All locomotives are outfitted with the system.
Nearly all of that track work was done by Amtrak, which uses that track for its Acela service.
Transit Matters, a Boston transit watchdog group, made this prediction last year.
"It is an accident waiting to happen and there is a good reason why the federal government has mandated all railroads install positive train control," said Marc Ebuna, of Transit Matters.
PTC is projected to cost about $450 million. And the MBTA expects 80 percent of that to come from federal loans and some grants. It announced last month that it secured $382 million from two federal infrastructure credit programs.
The MBTA expects to install the system on most of its lines throughout 2018. It started on the Fairmount Line this month.