An accident-prevention system required by Congress but resisted by the Metropolitan Transportation Authority would stop a train from speeding through a sharp curve and potentially derailing, experts said.
After years of rejecting the need for the system known as Positive Train Control, or PTC, the MTA last month approved a $400 million contract to install the systems on Metro-North and the Long Island Rail Road. The agency had unsuccessfully sought an exemption from the 2008 federal law requiring such a system. The MTA is still pursuing an extension of the 2015 deadline to have it in place.
Positive Train Control uses GPS and Wi-Fi technology. If a transponder installed on the tracks detects a train is going too fast, it automatically slows or stop the train. The federal mandate came after a 2008 commuter train and freight train collision in Los Angeles that killed 25 people.
LIRR president Helena Williams has said that while she thinks the MTA should be given more time to properly implement PTC, she is now sold on its benefits.
"I absolutely recognize that there are benefits to PTC," Williams said last month. "The wide scale launching of it is unproven, but the technology, we know, will work."
And it would have stopped the Metro-North train from entering the sharp curve north of the Spuyten Duyvil station at a dangerous speed, said David Rangel, founder of the Modoc Railroad Academy in Marion, Ill., an engineer-training facility.
"It would have taken control away from the locomotive engineer," Rangel said. "It's the automatic pilot of the railroad."
Earl Weener, the National Transportation Safety Board member leading the Metro-North investigation, said Monday that the train was traveling at 82 mph as it entered the curve where the speed limit drops to 30 mph from 75.
PTC would prevent "derailments caused by excessive speed," the Association of American Railroads, a trade group, reported, but cautioned that several challenges remain, including installing 20,000 antennas along tracks around the country and finding a way to make such a system operable among different railroads.
"The bottom line is everyone is doing all they can to implement this," association spokeswoman Holly Arthur said.
The MTA had argued that the 1920s-era crash prevention technology already on its railroads, known as automatic speed control, was sufficient to avoid accidents caused by speeding trains. That system similarly detects if a train has violated a speed signal. It will slow a train to about 15 miles per hour but will not stop it.
MTA officials would not say if the automatic speed control system was operating in the Metro-North train that derailed Sunday, killing four people and injuring 63.
Michael Quinn, general chairman of the Brotherhood of Locomotive Engineers and Trainmen Local 269, the union representing LIRR engineers, said that while he believes the existing brake backup system is "trustworthy," he supports the implementation of PTC.
"I think any technology that you can use that will . . . prevent human error is a good system," he said.