Energy saving in electrical railway traction systems has gained more and more relevance in the last years. As a matter of fact, the need for increasing speed in order to provide better quality services, implies an increase in energy consumption, and in operational costs. To keep the latter at the lowest level possible, it is possible to adapt the train's operating conditions according to appropriate rules based on measurements of characteristic train's and system's quantities. In this way, it is possible to have thorough information about train's course, and then take decisions in order to improve service and reduce consumptions at the same time. In the following is presented an on-board monitoring system that measures electrical quantities of the train and sends acquired data to a control station through network connection. The application of such system to the optimization of the train course protocol is also presented.