How Transfer Hubs Shape Agglomeration: Evidence from Commercial Districts, Mobile Activity, and Land Prices in Seoul

Urban railway networks play a central role in reshaping urban spatial structures, commercial activity, and population distribution. This study investigates how different transfer hub types in Seoul—a megacity with one of the world’s densest rail systems—affect nearby commercial clusters, active population agglomeration, and land values. We classify 298 stations into single-line (non-transfer) and multi-line transfer types and examine three aspects within a 500 m station catchment area: the density of surrounding commercial areas, active population agglomeration derived from mobile phone data, and land price changes using government-assessed land values from 2016 to 2024. To capture local variations, commercial areas were categorized as Developmental Commercial Areas, Commercial Alley Areas, and Traditional Markets. The results show that multi-line transfer hubs host denser commercial facilities and attract larger active populations than single-line stations. Active population varies significantly by station type, averaging approximately 1520 persons near single-line stations, 1969 near subway–subway transfer hubs, and 1637 near subway–rail transfer hubs. However, land price increases were more strongly influenced by the overlap and extent of station catchment areas than by transfer type alone. Robustness checks using alternative catchment specifications indicate that the main qualitative land-price patterns are stable with respect to the definition of the influence area. These findings contribute to understanding of how transfer hierarchy influences urban agglomeration and provide policy insights for typology-based transit-oriented development (TOD) planning in megacities.