The engineer operating an Amtrak train that derailed near DuPont told federal investigators he was planning to brake about one mile before the curve, but didn’t see a key milepost marker or a speed warning sign before the curve.

The 55-year-old engineer told investigators he recalled the train traveling at about 79 miles per hour about four miles before the curve at milepost 15.5, according to a report released Thursday from the National Transportation Safety Board.

The engineer told investigators during an interview last week he saw milepost markers 16 and 17 but did not see milepost marker 18 or the 30 mile per hour advance speed sign, which is posted about two miles out from the curve.

He told investigators he did see the wayside signal at milepost 19.8 at the curve, but he mistook it for another signal north of the curve. As soon as he saw the 30 mph speed sign just before the curve, the engineer told investigators he applied the brakes.

Seconds later, the train derailed.

Three people were killed and dozens more were injured in the December 18 derailment. Data from the rear locomotive showed the train was traveling nearly 50 mph over the speed limit at the time of the derailment.

The engineer told investigators he felt rested at the start of his shift, and the conductor in the car with him told investigators the engineer seemed alert.

The 48-year-old conductor told investigators that he spent most of the trip looking at his paperwork to familiarize himself with the territory.

He told the NTSB he looked down at his copies of general track bulletins just before the crash. The conductor said he heard the engineer mumble something, and when he looked up, he sensed the train becoming airborne.

The engineer, who has been with Amtrak since 2004, completed seven to 10 observational trips while he was qualifying on the Point Defiance Bypass section of the track. He operated the equipment on three trips, two northbound and one southbound.