System and method for controlling at least one of tractive or braking efforts of a vehicle system

System including an effort-monitoring system is configured to control tractive efforts (TEs) individually produced by propulsion-generating vehicles in a vehicle system. The effort-monitoring system is configured to control each of the propulsion-generating vehicles to provide a respective prescribed TE. The vehicle system operates at a system TE when each of the propulsion-generating vehicles is providing the respective prescribed TE. The prescribed TEs are determined by at least one of an operating plan of the vehicle system or a regulation that limits TE or ground speed of the vehicle system. In response to determining that a first propulsion-generating vehicle is providing a reduced TE that is less than the prescribed TE of the first propulsion-generating vehicle, the effort-monitoring system is configured to control a second propulsion-generating vehicle to exceed the prescribed TE of the second propulsion-generating vehicle so that the vehicle system is operating at or below the system TE.