The FRA will not identify which train line is involved or when the incident happened. The agency says Metra is investigating. Metra says it heard about the incident two weeks ago and acted immediately.
"if in fact these allegations are true, we will expect very swift proactive actions taken not only by the union, but certainly by Metra," said Judy Pardonnet, Metra spokesperson.
Pardonnet stressed that the workers deserve due process, and the investigation is in its early stages.
Metra would not say whether passengers were on board the train.