An energy management system and method for a vehicle system operate the vehicle system according to a current trip plan as the vehicle system travels along a route during a trip. The current trip plan designates operational settings of the vehicle system. The system and method also revise the current trip plan into a revised trip plan responsive to current, actual operation of the vehicle system differing from the current trip plan by at least a designated threshold amount. The revised trip plan designates operational settings of the vehicle system and includes an initial designated operational setting that matches the current, actual operation of the vehicle system.