The deliverable presents the initial set of requirements and the specification of the modules to be developed within the RIDE2RAIL project. In addition, it analyses the software developed in previous Shift2Rail projects to determine whether the functions developed in RIDE2RAIL can be integrated into existing artifacts. To determine the requirements and the specification of the RIDE2RAIL modules, the deliverable identifies the external actors with which the RIDE2RAIL modules will interact; then, it presents a set of use cases that provide an initial understanding of the functions to be realized in the project; from the use cases, a set of requirements are derived, then an initial model of the components to be developed in the project and their interfaces are provided in the form of a UML model. The set of functions to be developed in the RIDE2RAIL projects can be grouped in two categories: - those related to the interaction of the users (which can be passengers or drivers of shared rides) with the system, which should be provided through a suitable user application; - and those related to the management of shared rides, which should be provided by a Travel Service Provider. The deliverable analyses the feasibility of the integration of the RIDE2RAIL modules into existing frameworks. To this end, it analyses the outcomes of three projects: (i) the Travel Companion developed within the ATTRACkTIVE Shift2Rail project, which can be the basis for the application offering the functions targeted to users; (ii) the CIGO! platform of the My-TRAC Shift2Rail project, which could be used to realize functions for the monitoring of shared rides; and (iii) the software components developed within the SocialCar H2020 project, which could be the basis for the implementation of the RIDE2RAIL Travel Service Provider.