This Metro Silver Line train derailed just outside the East Falls Church on July 29, 2016. (Nikki Kahn/The Washington Post)

Metro has fired at least one additional worker as part of an investigation into falsified track inspection reports, with union officials saying that two others also have been terminated as part of a string of disciplinary actions that have decimated the department.

At a news conference with union officials Wednesday, former Metro track inspector Trap Thomas said he was called into his supervisor’s office Wednesday morning and informed he was being fired for falsifying reports.

Metro spokesman Dan Stessel declined to comment, saying “the process is ongoing.”

But Jackie L. Jeter, president of Amalgamated Transit Union Local 689, said a total of seven rank-and-file employees have been fired — three more than announced by Metro last month.

She said the allegations that workers falsified reports are untrue, and that Metro has provided no evidence or documentation to prove that workers did anything wrong.

“Specifically, what did they do?” Jeter said, calling on Metro to release a copy of the audit it performed on inspection reports. “Give it to us in writing.”

The union will fight the firings, she said.

Thomas, a nine-year veteran, said he never filed falsified reports — in fact, he said, on multiple occasions dating back to 2011, he tried to draw attention to egregious track defects in urgent need of repair. He said that when he did so he experienced retaliation — in one instance, he was hauled into an office for a barrage of drug and alcohol tests, for no apparent reason, he said.

Thomas made similar allegations in interviews with Metro officials during the investigation into the July 29 derailment of a Silver Line train, transcripts of which were published last month by the National Transportation Safety Board.

Thomas said he filed complaints with the Metro’s Office of Inspector General, as well as the federal Occupational Safety and Health Administration.

“I want them to know how dangerous it is,” Thomas said Wednesday.

Metro captured headlines last month when Metro General Manager Paul J. Wiedefeld announced that he was firing, suspending or disciplining 28 track inspectors and supervisors — nearly half of the track inspection department — after an investigation into the July 29 derailment at East Falls Church suggested that it was a widely accepted practice within the department to complete reports for inspections that had not actually been performed. Wiedefeld said that four inspectors and two supervisors were terminated, though he warned that more firings might follow.

“This review revealed a disturbing level of indifference, lack of accountability and flagrant misconduct in a portion of Metro’s track department, which is completely intolerable,” Wiedefeld said at the time.

In a statement released during Wednesday’s union news conference, Wiedefeld said his actions last month were necessary to “hold ourselves and each other accountable.”

“We cannot condone falsification of documents, and I stand by the actions we have taken that hold both front line and management employees accountable,” Wiedefeld said.

After those terminations became public, union officials argued that any wrongdoing by workers was likely a product of poor training and bad management, rather than intentional negligence.

In the internal Metro interviews published by the NTSB, Metro managers surmised that the inspection reports were falsified because the exact same measurements of track widths and heights appeared over and over again, month after month, without almost no fluctuations — which they said was highly unlikely.

But Thomas insisted Wednesday that the measurements stayed the same month after month because the tracks hadn’t moved. Only in the days leading up to the derailment, when the crossover between tracks was in constant use because of SafeTrack single-tracking, did the tracks begin to spread apart to a dangerous width.

Union officials also offered a memo published by Metro in 2010, highlighting the agency’s own policies which state that such crossovers are supposed to be inspected twice per day when they are used for single-tracking, because of the additional wear and tear. If managers were enforcing that protocol, union officials argued, the dangerous width of the tracks would have been caught before the derailment.

“You cannot have a systemic problem and reduce it to one issue. It doesn’t work like that,” Jeter said.

News of the additional firings came during a news conference at the AFL-CIO’s Washington headquarters, where union officials and several outside consultants argued that Metro was unfairly blaming low-level employees for safety lapses and failing to punish managers and supervisors who had allowed or encouraged lapses in safety protocol for years.

“The decision-makers at [the Washington Metropolitan Area Transit Authority] are being shielded and protected, while our employees are being scapegoated and silenced,” Jeter said, though she added that she believes at least three supervisors have also been fired within the past month.

The dispute also comes in the midst of contentious contract negotiations between Metro and its largest union. Jeter said that Metro has failed to respond to requests from the union that language be included in the contract that would clarify and define workers’ and managers’ safety responsibilities.

She pointed out that nine Metro workers have been killed on the job in the last 11 years.

Union officials also used the occasion to air some of their grievances against Wiedefeld, who stepped into his role at the top of Metro just over a year ago.

“That is just another form of intimidation,” said Lawrence Hanley, ATU international president. “He’s firing people at the bottom of the food chain.”

The union also brought out Metro track walker Rodney Hawkins, a 27-year veteran, who said that Metro management has declined to make changes to inspection protocol that would increase safety for workers or help them perform more exhaustive inspections.

In particular, Hawkins said track walkers should be assigned to inspect in pairs, rather than individually, to ensure they don’t miss any defects. Additionally, he said, the agency should provide inspectors with lights or beacons to warn operators of oncoming trains that people are on the tracks.

This is an important measure, union officials said, because inspectors are often fearful of spending too much time at interlockings — where two sets of tracks cross over each other — because traffic could come from four different directions.

“This is a disaster waiting to happen,” said Roger Toussaint, a former New York City track walker and union official who is now an ATU consultant. “People are going to be killed because of unsafe flagging procedures that WMATA has institutionalized.”

Stessel said the beacons are being considered by safety managers.