Wider Effects are impacts that the realisation of new infrastructures have on the development of the economic and social framework. In Italy, the evaluation of railway investments is governed by the guidelines entitled "Linee guida per la valutazione degli investimenti in opere pubbliche", published by the Ministry of Infrastructure and Transport (2017). In this context, the main methodology used to measure the soundness of an investment is cost-benefit analysis, which focuses on the transport benefits generated by the project, such as travel time, fuel and operating cost savings, environmental benefits, and so on. The guidelines consider wider effects that go beyond the impacts analysed by the CBA, which, although not recognised as key elements in the investment decision-making process, are nevertheless seen as essential community benefits. These latter effects can be estimated through the interaction between the transportation infrastructure and the territory. In particular, the guidelines define the indirect wider impacts of transport investment as those arising from other macroeconomic sectors and different markets that might result from a new transport supply (e.g. impacts on employment, international trade, demographic developments, and so on). It is well known that these impacts are extremely important, and can significantly influence the social return on an investment, especially in times of crisis. In order to estimate the indirect macroeconomic effects, it is possible to construct a model based on relationships between sectors, at the national (or regional) scale. This model measures the economic impacts (i.e. on labour market supply and demand, imports and exports, trade, productivity, etc.), based on the effects (both short/medium term, related to increased expenditure during the construction phase, and long term, linked to a change in accessibility and transport costs) resulting from the use of the new transport infrastructure. According to the literature in the field, the term "Wider effects" refers to benefits associated with changes in the economic and residential field, tourist flows, accessibility of the territory and economic activities, upgrading of the real estate, land regeneration, and territorial competitiveness, which generally occur after a renovation or the construction of new transport infrastructures. The importance of the latter effects is even more remarkable when the territories considered are under development or have low accessibility, as in these cases the wider effects could significantly affect the social and economic landscape. In this paper will present the case study of the Palermo-Catania high-speed rail link. This investment aims to upgrade the Palermo-Catania railway connection by improving the Fiumetorto-Bicocca section to expand the existing single-rail capacity and to increase the speed limit to 200 km/h. As part of the evaluation of the Palermo-Catania high speed link, several wider aspects were considered to enrich the benefits assessed by the cost-benefit analysis. The following aspects were also computed by referring to the same perimeter considered in the CBA. Short-term effects, during the construction phase:. Value Added and employment. Long-term effects, during the operation phase:. Accessibility. Contribution to inequality reduction (Gini Index). Agglomerative effect
