Bearings give warnings before they get hot, but problems cannot be reliably detected from the wayside because of ambient audio noise and the 'air gap' problem. Brake-feedback is also desired by the railroad industry. This will provide real-time confirmation of the application and release of the brakes on each and every car. Also on-line information about slack adjusters will displace maintenance labor and improve safety. The magnitude of the installation effort asserts a singular logistical challenge.
Total interoperability is a long way off.
Some railroads have expressed reluctance to keep a 100-car train out of service longer than two weeks. That makes for an upper bound of 2.4 hours per car. What is beneficial for rolling is not so good for stopping. Heavily loaded trains, therefore, suffer excessively long stopping distances. Each freight car can be equipped with load cells that provide sensor data permitting the ECP Brake system to increase the local braking effort to match the load.