There were no reported injuries, officials said.
Fire department spokesman Mark Brady said the locomotive “hit a derailer on a side track, which triggered an intentional derailment and resulting in “a small diesel fuel spill.” Such derailers are installed as safety devices. The train was headed for a main track at the time, Brady said. It was unclear if the train was being operated remotely.
Brady said fire department hazardous material crews assisted CSX with the clean-up. Bob Sullivan, a CSX spokesman, said the fuel spill had “all been contained.”
The incident did not cause any evacuations or disruptions to commuter rail and vehicle traffic, officials said.