2 struck and killed by Amtrak train in Washington, DC There were no injuries on the train to passengers or crew.

 -- Authorities are investigating after two railroad employees were killed on Tuesday night after being struck by an Amtrak train as it approached Union Station in Washington, D.C.

The victims were employees of CSX Transportation, the railroad company confirmed. They have not yet been identified.

Amtrak and the National Transportation Safety Board are investigating.

"Our thoughts are with the families and friends of our employees," CSX Transportation said in a statement Wednesday morning. "CSX management representatives responded to the scene to assist with the investigation of this tragic incident. At this time, the names of the involved employees are being withheld out of respect for the privacy of their families."

Officials said that while Amtrak Train 175, heading from Boston via New York, was approaching Washington's Union Station at about 11:18 p.m. ET on Tuesday, the two CSX workers were struck on the railroad tracks near the intersection of 9th Street and New York Avenue Northeast. There were no injuries to the train's crew or 121 passengers.

"Circumstances of the incident are under investigation. Amtrak will work with the D.C. Metropolitan Police Department and others to review the incident," Amtrak said in a statement Wednesday morning. "Amtrak was particularly saddened that incident involved fellow railroaders employed by CSX."

Amtrak spokesman Marc Magliari initially said the two people struck appeared to be trespassing in the area.

The company said it is working with D.C. Metropolitan Police Department and others to review the matter. Amtrak service is expected to be restored by midmorning Wednesday.

The two deaths were confirmed by D.C. Fire and EMS on Twitter.

ABC News' Jeffrey Cook and Morgan Winsor contributed to this report.