The National Transportation Safety Board is investigating an accident at a rail yard in Decatur, Alabama that killed a Norfolk Southern worker last week.

Three NTSB investigators spent several days at the site of the January 31 accident.

At about 5:15 p.m. that day, a railroad engineer was in a locomotive that was struck by freight cars in the rail yard, according to the NTSB.

The Brotherhood of Locomotive Engineers and Trainmen union identified the engineer who died as 55-year-old Chris M. Wilson, who had been an employee of Atlanta-based Norfolk Southern for 30 years.

“Norfolk Southern is grieving the loss of a member of our team and our hearts are with their loved ones during this extremely difficult time. We are cooperating fully with the NTSB to understand what happened,” Norfolk Southern said in a written statement.

It could take one to two years for the release of a final report detailing the probable cause of the crash and any contributing factors, according to the NTSB.

“This tragic loss underscores the safety risks present in railroading, even in the controlled environment of a rail yard,” said Eddie Hall, national president of the Brotherhood of Locomotive Engineers and Trainmen, in a written statement.

From 2014 through November 2023, the Federal Railroad Administration (FRA) recorded nine deaths of Norfolk Southern employees on duty. There was one employee death a year from 2020 through 2023, two in 2019, two in 2016 and one in 2015.

Last March, a Norfolk Southern conductor was killed when his train was struck by a dump truck while moving through a rail crossing in Cleveland, Ohio. After the accident, Norfolk Southern CEO Alan Shaw pledged to “rebuild our safety culture from the ground up.”

That same day, the NTSB announced an investigation of Norfolk Southern’s safety culture.

Last August, the FRA made a series of recommendations for Norfolk Southern to improve its safety operations, on top of previous recommendations in a 2022 system audit after three Norfolk Southern employees suffered amputations while on duty.

Norfolk Southern has said it is investing in safety improvements broadly across its system. This week the railroad said its infrastructure improvements included the installation of 108 hot box detectors that can detect overheated bearings, 17 acoustic bearing detectors and other safety infrastructure added in 2023.

At a site near East Palestine, Ohio, where a Norfolk Southern train carrying hazardous materials derailed in February 2023, the railroad last fall added a digital train inspection portal developed with the Georgia Tech Research Institute. Another is under construction near Jackson, Georgia, and more are planned across the railroad’s system.