ATP/ATC subsystem testing and validation using a HIL test rig

Abstract

Automatic Train Protection (ATP) systems ensure that trains comply with speed restrictions and prevents them passing red signals. They are designed in order to automatically act to slow or stop the train where trains exceed speed limits or pass signals at danger. Their safety and reliability is then crucial for the safety and efficiency of the whole railway system. A correct estimation of distance to target and actual velocity is fundamental to evaluate residual braking resources, in terms of available deceleration, in order to reach the targets at the required speeds. The so-called odometry algorithm is the ATP subsystem devoted to train speed and travelled distance evaluation: it is composed by a series of sensors and a software procedure that acquires and manages the information from the sensors. Odometry estimation accuracy has a great influence on the whole ATP system behavior and then has to be carefully designed and verified. The validation of such devices could be performed with test runs, but this procedure has some disadvantages, for example, it is expensive and presents management difficulties (since these test activities have to be integrated with the normal rail traffic), testing conditions are not completely controllable etc. In order to overcome all these problems, Trenitalia S.p.A. and the Energetics Department of Florence University has designed and realized a HIL (Hardware In the Loop) test rig for the type approval of odometry devices. In this work the main features of the odometry device developed for the Italian ATP system (named SCMT) will be shown, the criteria used to design the tests will be resumed, then the architecture of the test rig will be presented. The final part of the work will summarize the results obtained from the testing activities and an estimation of the odometry subsystem performance (in terms of speed and travelled distance accuracy).