An unoccupied train on the Long Island Rail Road's Long Beach branch partially derailed early Tuesday morning, throwing off service throughout the day. 

The MTA says the accident happened when the engineer was moving the empty train slowly just north of the Long Beach station just after 5 a.m.

"In the process, the driver became aware that something happened, so he stopped it immediately, and the observation was that it was partially derailed," said MTA Chairman Joe Lhota. 

The derailment forced the shutdown of the entire Long Beach branch for several hours during the morning rush. The MTA says it immediately pulled buses from its commuter lots to move stuck riders in Long Beach to the nearby Island Park station.

The delays, which were up to a half-hour throughout the day, couldn't have come at a worse time for Elizabeth Sullivan. Tuesday was the first day of her new job in Manhattan.

"It's the 'Summer of Hell,' but this is the MTA," she told News 12. 

By 3 p.m., the MTA started running trains through the area again.

The MTA says it did put out text message alerts to riders warning them about the service changes.