OREANDA-NEWS. US safety officials today found that excessive speed caused by a distracted engineer is the root cause of a fatal derailment of an Amtrak train in Philadelphia in May 2015.

The lack of a positive train control (PTC) system was discussed, but rejected, as a probable cause.

The National Transportation Safety Board (NTSB) met today in Washington, DC, to analyze staff findings regarding the 12 May, 2015 derailment that killed eight people and injured more than 200.

PTC was central to NTSB's discussion of the derailment, which the agency said happened after an engineer became distracted by radio communications about projectiles that were hitting other trains in the area. Amtrak Northeast Regional train #188 was traveling at 106mph on a section of track with a 50mph speed limit when it ran off a curve and crashed. The train had just passed a stopped Southeastern Pennsylvania Transportation Authority train with a broken windshield.

NTSB has stated since shortly after the accident that PTC would have prevented it, and has had PTC on its technology wish list since 1970. PTC is a computerized safety system that can automatically slow trains and prevent some types of collisions.

NTSB vice-chair T. Bella Dinh-Zarr today sought to put the focus on PTC, unsuccessfully proposing that its absence be listed as probable cause, rather than a contributing factor, of the Philadelphia derailment. The board voted 3-1 against Dinh-Zarr's proposal.

"If PTC were in place, we would not be here today," Dinh-Zarr said, adding that PTC could have prevented dozens of fatalities and train accidents. "It is time to take a less myopic view of the probable cause of these accidents."

She added that: "We have technology, and why are we not using it, and why are we not highlighting it?"

Other NTSB members said that the focus for railroad safety should be on human performance. NTSB has listed PTC as a contributing factor in 25 accidents in recent decades.

NTSB staff recommended against naming PTC as a probable cause of the Philadelphia accident because the engineer has primary responsibility for operating the train safely, and PTC does not change that.

A finding that lack of PTC was a probable cause could have drawn more scrutiny on Class I railroads that are installing the $9bn system. Railroads last year successfully pressured Congress to extend the 31 December, 2015, deadline to have the technology installed.

The Philadelphia derailment occurred as railroads were lobbying Congress to extend the deadline it set in 2008 for PTC to be installed on the US Class I network. Railroads said they would have to shut down their lines to passenger and freight trains on 1 January, 2016, if Congress did not extend the deadline.

Congress ended up extending the deadline to as late as 2020 in some cases. Canadian National, CSX and Norfolk Southern say they will not have PTC installed until 2020. BNSF, Kansas City Southern, Union Pacific and Canadian Pacific are on track to have it installed by 2018.

Amtrak has made PTC operational on the section of track in Philadelphia where the accident occurred, as well as most of the Northeast Corridor.

The mandate by Congress to install PTC came after 25 people died and more than a hundred were injured in a collision of a Union Pacific freight train and a Metrolink commuter train in Chatsworth, California, on 12 September, 2008. NTSB blamed the Metrolink engineer, saying he was distracted by text messages as he ran a red signal, causing the collision.