The engineer whose Amtrak train derailed last May in Philadelphia, killing eight people, was likely distracted as he sped to more than 100 m.p.h, a yearlong federal investigation will conclude Tuesday, according to network television reports and a congressional source briefed on the findings.

Among the possible reasons the engineer may have lost his bearings was radio chatter several minutes before the train hurtled off a curve, according to a second source familiar with the study by the National Transportation Safety Board.

The NTSB findings, first reported by NBC News, come on the eve of a safety board hearing in Washington that will largely bring to a conclusion the investigation into the Train 188 crash, which also injured 200. On Tuesday, the board will review the results of the investigation and reach likely conclusions about its cause.

Since shortly after the crash, speculation in railroad circles and in Washington has centered on the idea that the engineer might have simply lost track of where he was as the train approached the curve.

Among the recommendations NTSB investigators are making are that Amtrak develop better training for engineers and that the Federal Railroad Administration study whether having two engineers or other crew operating the trains would be safer than one engineer.

The recommendations, obtained by the Inquirer and the Daily News, also address Philadelphia's preparedness for a mass casualty event, calling for increased consistency among police, firefighters, and other first responders.

In the minutes before the May 12 derailment at the Frankford Curve, rocks struck an Amtrak Acela train and a SEPTA train traveling through Philadelphia. The Acela was hit about 9:05 p.m. A rock hit the SEPTA train's windshield at 9:10, forcing it to stop.

Train 188 derailed at 9:21, and the engineer, Brandon Bostian, described to investigators hearing three or four messages about the damage to the SEPTA train over his radio in the minutes before the crash.

The messages, Bostian said, left him slightly concerned about his safety.

"I was really concerned for the SEPTA engineer," he said, according to NTSB transcripts. "I had a coworker in Oakland that had glass impact in his eye from hitting a tractor-trailer, and I know how terrible that is."

Bostian radioed the SEPTA train as his New York-bound train passed it, to make sure the operator of the stationary vehicle was aware that the adjacent track was in use. He never received an answer.

The incident didn't overly worry him, Bostian said.

"Whoever was throwing rocks and shooting probably had left," he told investigators. "I wasn't, you know, super-concerned, I don't think."

Four miles past the SEPTA train, Train 188 train derailed. Investigative documents show Bostian's train entered the curve going 106 mph, more than twice the posted speed for that turn. Bostian had the train at full throttle for about 55 seconds before reaching the curve, according to the train's data recorder. He maintained that speed for 30 seconds, slowed for two seconds, then pushed the throttle to full again for 20 seconds.

In his comments to investigators, Bostian seemed to indicate being surprised at how fast he was traveling moments before the derailment.

"That's when I realized that it wasn't that the train was going somewhat fast around the curve," he said. "The train was going significantly fast around the curve."

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