With new rail lines, residents can enjoy higher accessibility and more activity opportunities. However, better access to public transport can potentially increase land prices in catchment areas. In this research, we aim to investigate whether this capitalisation effect goes beyond the conventional catchment area and how such an effect varies across different regions. In a departure from previous studies, we employed a gravity-based accessibility measure to capture the regional impact of rail lines using a cross-sectional analysis of 2001 and 2011 residential apartment data in Hong Kong and a difference-in-difference approach to estimate repeated sales transacted in both years. We used a three-level hierarchical estimation method that allowed the price effect to vary by submarket. The results indicated that the network accessibility of rail lines had a statistically significant capitalisation effect on property prices that varied across different submarkets. Although the three major new rail lines had a greater impact on the built environment in suburban areas, the elasticities in property price with regard to accessibility were still larger in urban areas in both 2001 and 2011. We also establish that the improvements in rail accessibility had a substantially greater effect on the changes in property price between 2001 and 2011 in several new town submarkets along the new lines. From a regional perspective, we conclude that the price effect of new transport infrastructure goes beyond the local catchment areas and call for urban policies that address housing affordability issues across different submarkets in the region and a re-examination of land value capture policies.