Abstract: To reveal the current status and future development trend of research in the field of carbon emissions from railway tunnel engineering, a systematic review of the current research, hot topics, and future developments in the field of railway carbon emissions is conducted based on the theoretical approach of bibliometrics and knowledge mapping. Based on the literature on railway carbon emissions in the Web of Science database from 2008 to 2022, the statistical analysis of the number of articles, frequency of citations, and Web of Science category distribution of railway carbon emissions research literature is conducted using CiteSpace and VOSviewer econometric analysis software. The data are analyzed visually in four aspects, including institutional cooperation network, cooccurrence of subject terms, cocitation of literature, and detection of emergent words. The results show the following: (1) The number of publications of railway carbon emissionrelated literature fluctuated during the period 20082022, with an overall trend of slow and then sharp growth. The number of citations of literature showed a significant growth trend. The research focused mainly on the calculation of carbon emissions during the tunnel construction period, and the uncertainty of carbon emission accounting during the tunnel operation and maintenance phase was large. (2) In the research of lowcarbon materials and lowcarbon construction measures, there were more research on the analysis of tunnel construction carbon reduction, and less research on the analysis of specific targeted emission reduction effects. (3) In terms of the evaluation of carbon emissions, the lifecycle evaluation method and the comprehensive evaluation method were the main ones, but there was no standardized standard for the evaluation indexes. Through the analysis of the frontiers, it can be seen that there is a huge research potential in the future in the establishment of carbon emission calculation standards for railway tunnels, improving the data of carbon emission factors, evaluating and predicting carbon emissions, optimizing the construction scheme and mechanical equipment, and so on

Key words: railway tunnel project, knowledge mapping, carbon emissions, bibliometrics, visualization analysis