This report is the first deliverable for Work Package 4.2 under Sub- Project 4 (SP4) of the Capacity4Rail project. The aim of this deliverable is to set out the basis for the selection of the most suitable components of the monitoring system, such as devices, methods and tools, to be integrated in upgraded and new infrastructure elements leading to the achievement of the general goals of the Capacity4Rail project, i.e. the design and development of an affordable, adaptable, automated, resilient and high capacity railway system. First of all, a set of functional and technical requirements at low level, mid level and high level has been defined. Once scored, the features of the monitoring components can be assessed together with their cost in an evaluation framework (spreadsheet) developed to this end, giving the best value to the solution that better meets the functional and technical requirements at minimum cost. This methodology will be helpful in the work to be done in Tasks 4.2.2 and 4.2.3, in charge of the selection of sensor, energy harvesting, communication and data integration technologies.