National Transportation Safety Board members clashed Tuesday over what caused last year’s fatal Amtrak derailment near Philadelphia, before the split body pinned blame on the speeding engineer.

The board voted, 3-1, in finding that Train 188 crashed because the operator failed to notice his speed had reached 106 mph, hitting a 50 mph curve just north of Philadelphia’s 30th Street Station.

Board vice chairwoman T. Bella Dinh-Zarr cast the dissenting vote after she had proposed shifting primary blame to the train’s lack of state-of-the-art GPS technology known as Positive Train Control (PTC).

“Positive train control would have provided this critical redundancy that would have prevented the accident,” Dinh-Zarr said. “The government and industry have not acted for decades on a well-known safety hazard.”

But NTSB staff investigators and other board members disagreed, arguing that countless other trains travel across America every day also lack PTC technology – but somehow don’t crash.

Dinh-Zarr’s proposal – to boost the lack of PTC technology from a “contributing factor” to “probable cause” – was defeated 3-1.

Despite voting down Dinh-Zarr’s language, the NTSB agreed that modern technology could have prevented this tragedy.

Had PTC been in place on Train 188, “we would not be here today,” said NTSB investigator Ted Turpin.

Eight people were killed and about 200 injured when the northbound Amtrak derailed on May 12 of last year.

The NTSB found that operator Brandon Bostian was distracted by radio chatter – about rocks being thrown at a nearby Southeastern Pennsylvania Transportation Authority (SEPTA) that night.

The rock attack shattered glass into the face of a SEPTA engineer, officials said “The Amtrak engineer may have lost situational awareness,” NTSB investigator Steve Jenner said. “In short, situational awareness is having accurate understanding of what is happening around you and what is likely to happen in the near future.”

Just a few moments of distraction was all it took to prompt the tragedy.

“He went, in a matter of seconds, from distraction to disaster,” NTSB board member Robert Sumwalt said.