While individual urban transport operators have in the past thirty years been at the forefront of introducing advanced systems such as ATS (automatic train supervision), ATP (automatic train protection), ATO (automatic train operation) and driverless or unmanned trains this has been carried out on a case-by-case basis, in accordance with the guidelines and specifications developed for each system. In large part this is due to the absence of pressing practical necessity for interoperability and intermodality of the type encountered in mainline rail systems, particularly when operating across national boundaries. The barriers to mass market in mass transport technologies are not primarily technical: overwhelmingly they are institutional, legal or rooted in corporate cultures. The task to overcome these obstacles is challenging and political. The starting point, however, is to develop an agreed set of requirements as a basis for a common management system.