Abstract: A digital train brake testing and train preparation assistant uses a system, method, and computer program for determining a component parameter of a train. The system may include sensor nodes mounted to a respective part of the train, wherein the sensor nodes form a sensor network on a rail car, wherein railcars form a wireless mesh network, and wherein each of the sensor nodes is configured to collect data of the component of the respective part of the train and to publish the collected data into the wireless mesh network. The system may further include a server system configured to receive the published data of the wireless mesh network and to determine the component parameter of the train based on the received data. Furthermore, a user device for displaying a component parameter determined by a system, method, and computer program for determining a component parameter of a train is provided.