ELIZABETH, N.J. (AP) _ Four cars of a 59-car freight train went off the tracks early Wednesday, causing delays for commuter trains.

The CSX train, being operated on Amtrak tracks, was headed from Selkirk, N.Y., to Metuchen, N.J., with a load of parts for auto assembly plants. No injuries were reported.

The cause of the derailment, which happened about 2 a.m., was not known.

The derailment delayed thousands of rail commuters who had to be put on buses and driven around the accident Wednesday. Crews expected to have the train on its way by late evening.

NJ Transit rail riders and Amtrak passengers faced delays of up to 20 minutes on the Northeast Corridor and North Jersey Coast Line. Minimal delays were reported after 8 a.m., said Cecilia Cummings, a spokeswoman for Amtrak's Northeast Corridor.

``We came through much better than we expected to in terms of delays,'' she said.