Traditionally, applications of the railroad industry were based on analog information exchange using wired technologies. The evolution of wireless technologies that allow the exchange of any kind of information, has led to the emergence of a new scenario in which it is possible to exchange any kind of information between trains and Ground Control Centers. In addition, there has been a revolution in the railways that requires new applications and services that provide additional functionality to safety and schedules compliance. With all this, it is needed to establish a wireless communication mechanism that allows the exchange of information enabling the integration of existing applications and easy deployment of new applications. This paper presents the results of the work done during the last three years along railway companies to design a communications architecture that allows standardizing the exchange of information between terrestrial applications and train-side systems.