The Clocker was a passenger train service between Philadelphia and New York City on the Northeast Corridor at first by the Pennsylvania Railroad and later by Amtrak.

The service was nicknamed the Clocker by riders as trains were scheduled to leave each terminal at the top of the hour.

Amtrak discontinued the service on October 28, 2005, and it was partially replaced by additional NJ Transit express trains between Trenton, New Jersey, and New York City at times approximating the Clocker schedule.

The Clocker was originally a Pennsylvania Railroad express train service between New York and Broad Street Station in Philadelphia;[1] the name was unofficial, and PRR timetables did not use it.

On October 28, 2005, Amtrak discontinued the Clocker service altogether and sold the Northeast Corridor operating slots to NJ Transit which used them to partially replace the service with additional Northeast Corridor Line express trains between Trenton and New York City at times approximating the Clocker schedule.