Hindi and English are official only for Parliamentary proceedings and Judiciary/administrative interactions between the state and the center. For any other activity, all of the 22 languages recognized as official languages by the constitution ( and English ) are equal and the individual or the organization is free to choose which language to use. Usually languages officially recognized by individual states are given priority over others. It all depends on what IR decides to use. They can choose to have announcements in any of the constitutional official languages recognized by the states to which the terminals of the train belong.