An Amtrak worker held responsible by federal investigators for a 2016 train derailment in Chester has filed a lawsuit against the railroad agency and his former union, alleging civil rights abuses.

William Robinson, a night foreman, is challenging the disciplinary process that led to his firing in May 2017, arguing that he was one of two foremen responsible for tracks where Amtrak train 89 derailed on April 3, 2016, in Chester, killing two track workers. Robinson, who is African American, has been the only person fired in connection with the crash. The other foreman, John Yager, is white.

Robinson, 43, was "put out of service and lost his job while a white individual, John Yager, in similar or in fact more culpable circumstances, remains uncharged, happily headed toward retirement," Robinson's lawyer, Mark Schwartz, wrote in the suit.

Robinson filed in U.S District Court allegations of civil rights violations, racial discrimination, and maintenance of a hostile work environment on the part of Amtrak and the Brotherhood of Maintenance of Way Employees, the union representing track workers.

The derailment happened when the southbound Amtrak train struck a backhoe on the tracks while traveling 99 mph. Two Amtrak employees were killed. Thirty-nine passengers were injured on the train of eight passenger cars, a cafe car, and a baggage car traveling from New York City to Savannah, Ga. It carried seven crew members and 337 passengers.

Robinson was working on a rail cleaning project, and his night shift ended just before the train derailment at 7:50 a.m. The NTSB singled out both Robinson and the day foreman, Yager, for failing to ensure trains wouldn't travel on tracks where workers would be present.

Even though there were still workers on the tracks, Robinson canceled safety protections, known as foul time, when he ended his shift, the NTSB found in 2017. He also left the backhoe on the tracks even though he had released the protections that would have kept a disptacher from routing trains onto the tracks. Yager, meanwhile, never contacted a dispatcher to restore those protections when he began his shift. The day foreman also failed to give workers a proper safety briefing before they began work, as is required.

In an interview last year, Robinson said disorganization was the norm at Amtrak.

"There are many things that are done that I guess you would say aren't safe," Robinson said.

He contended that he was being scapegoated when it was the entire company that bore fault for the derailment.

While the NTSB found that both men's actions led to the crash, the larger problem was a poor safety culture at Amtrak, the agency concluded. Supervisors weren't confirming that workers were following procedure, and track workers weren't given vital pieces of equipment that would have warned a train dispatcher that there were men on the tracks.

Amtrak declined to comment on the suit filed Monday but has said in the past there may be more disciplinary action to come in relation to Train 89's derailment. The agency has also denied that race a role in Robinson's dismissal.

"We categorically deny that Mr. Robinson was disciplined, singled out or treated in any way differently because of his race," Amtrak spokeswoman Christina Leeds said in a November 2017 interview.

Robinson's suit describes a disciplinary process with the system stacked against him. He suspected the union representative assigned to assist him was racist, but that person did not recuse himself after Robinson raised those concerns, the suit claims.

A witness for Amtrak, an assistant division engineer, the suit states, lacked expert knowledge of track procedures during the hearing. And Amtrak's charging officer during the disciplinary hearing was using her phone and texting during the hearing, the suit claims.

Robinson contends that he was not allowed to call witnesses in his defense and was told his witnesses weren't relevant to the accusations against him.

Jed Dodd, the head of the union representing Robinson, said Tuesday that he had not seen the suit and did not want to comment on it but noted his union was in the process of arguing on Robinson's behalf in arbitration, saying his firing was "improper and without just cause."