This document specifies an additional SIRI functional service to exchange information about Control Actions, between monitoring systems and servers containing real-time public transport vehicle or journey time data. These include the control centres of transport operators, as well as information systems that deliver passenger travel information services. As for Transmodel, public transport modes include new modes of transport (vehicle sharing, vehicle pooling, etc.). This document describes the SIRI Control Action service, one of a modular set of services for the exchange of Real-time information. The Control Action service (SIRI-CA) is concerned with the exchange of information about decision made concerning the real-time management of the operation of a transport system as performed by operators while operating the services.