High-speed rail and socioeconomic inequality: a systematic bibliometric analysis of research trends, methodologies and thematic structures

This paper investigates how high-speed rail (HSR) influences socioeconomic inequality by providing the first systematic bibliometric review of research trends, methodological approaches and thematic structures. It examines whether HSR fosters balanced regional development or reinforces spatial disparities. Using the Bibliometrix R package, 237 records were retrieved from the Web of Science (1985–2024). Citation indicators, keyword co-occurrence and collaboration networks were combined with natural language processing (NLP) to classify studies by territorial scale, methodology, economic variables and inequality outcomes. The paper offers the first structured overview of how the literature conceptualizes the link between HSR and inequality. It highlights persistent gaps – scarcity of city-level analyses, limited socioeconomic indicators and reliance on Chinese case studies – providing a foundation for more comparative and interdisciplinary research. This paper contributes by offering a structured overview of how the literature has conceptualized and measured the relationship between HSR and inequality. By identifying persistent research gaps – such as the scarcity of city-level analyses, limited use of socioeconomic indicators, and overreliance on Chinese case studies – it provides a foundation for more comparative and interdisciplinary approaches. The study informs policymakers and researchers on how to design future infrastructure projects that balance efficiency with equity.