A system includes one or more processors configured to obtain operating parameters of a subsystem of a vehicle that is configured to travel along a route during a trip. The one or more processors are configured to generate a digital twin of the subsystem based on the operating parameters, and to receive simulated performance data generated by execution of the digital twin with a designated model of the subsystem. The one or more processors are further configured to obtain field performance data of the subsystem monitored by sensors onboard the vehicle during the trip, and to determine a performance composite index of the subsystem of the vehicle based on a variance between the simulated performance data and the field performance data. The one or more processors are also configured to control the vehicle during the trip or a subsequent trip based on the performance composite index.