Factors of air-rail intermodality

European transport policy promotes intermodality as a means of improving efficiency and sustainability. This study looks into passenger air-rail intermodality at airports which are directly integrated into long-distance rail networks and focuses on intermodal journeys in which the rail trip doesn’t serve the purpose of city-centre to nearby airport access, but rather makes up a substantial leg of the journey, potentially substituting short-haul air feeders and expanding airport catchment areas. Air-rail intermodality projects involve considerable capital and operating costs and require ambitious goals and strong cooperation among actors. Although best practice guidelines exist for intermodality in general, there doesn’t seem to be one best solution for air-rail intermodality success. By examining literature, European intermodal products and rail stations at airports, we propose five critical success factors: infrastructure integration, network context, overall travel time and transfer time, integrated ticketing and information. Governance factors were also found to be a key determinant of success for planning, implementing and operating these multi-operator projects which require high levels of coordination. Case studies examined best practice (Frankfurt airport) and compared a successful case with one which is not so successful (Paris-CDG versus Lyon Saint-Exupéry). Result transferability to Portugal was analyzed, focusing on Lisbon airport. As a result, we suggest three issues be taken into account when assessing the integration of Lisbon airport into the high-speed rail network – sufficient demand to justify adequate rail frequencies, sufficient provision of long-haul flights from Lisbon airport to capture demand and the existence of operator interest in offering intermodal products.