Updated

The head of New Jersey's commuter rail agency says it's unclear when full service will resume after Monday's train derailment in New York's Penn Station.

New Jersey Transit Executive Director Steve Santoro said Tuesday that eight tracks in the station are either unusable or partially usable.

Investigators are looking into why a NJ Transit train derailed just outside the station Monday morning. No serious injuries were reported. Service was disrupted throughout the day.

The Long Island Rail Road canceled 10 trains to Penn Station on Tuesday morning and terminated four others at Jamaica in Queens.

Amtrak says riders using Penn Station should expect delays of 30 minutes to an hour.