In this paper, we apply Data Envelopment Analysis (DEA) methodology to analyse the accessibility impact of the new high-speed train (HST) between Madrid and Barcelona. Accessibility is not usually defined; however, a great variety of indicators with different theoretical backgrounds and complexities has been proposed and implemented in empirical investigations. Here, we develop some synthetic indices to measure the accessibility impact of the new line using four complementary indicators: an index of location; economic potential; relative efficiency of the network; and daily accessibility. A geographic information system (GIS) was used to calculate these indices. The relative performance of each individual economic centre is discussed according to the results of these partial accessibility indicators, and DEA is used to obtain a better understanding of the overall performance of the new infrastructure. Thus, we propose two different synthetic indices to evaluate the accessibility overall performance. The results of the model will be used to extract some policy considerations with respect to the (polarising/balancing) effects of the line within the Spanish territory.