## 2 Introduction
### Research Review  
To gain a comprehensive understanding of the advantages of BIM applications in railway construction projects, the authors conducted a literature review on the relevant research, with a particular focus on cost-effectiveness and studies involving practical case applications. Within our analysis of the Web of Science database (WoS) of the combination of \"building information modeling (BIM)\" (title) and \"construction industry\" (topic), there are 1076 article publications (Dec 29, 2023). The result distribution by country and region show there are 276 papers published in China (25.65%), 158 papers in England (14.68%), and 133 papers in the USA (12.36%); the publication of South Korea has 66 papers which make up 6.13% (Figure 1). We selected and analyzed some of the publications that related to BIM application in railway construction. On the other side, the publications of WoS by research area show that there are 714 (66.357%) papers in the engineering area were published, construction buildings have 393 papers set up by 35.524%, and business economics have 145 papers set up by 13.476% (Figure 2).  
Figure 1: Top 10 publications of WoS by Countries/Regions.  
In these related publications, [PERSON], [PERSON] et al. proved that BIM applications could reduce 50% of time costs and reduce costs by 52.36% [10]. [PERSON], [PERSON] et al. revealed the critical importance of accurate cost estimation and quantity surveying for effective budgeting and cost control in achieving cost benefits [11]. BIM application through collision detection allows for the early identification of design errors, ensuring timely issue resolution before construction. Due to technical staff checking for errors in advance, thereby reducing additional construction periods and saving costs in a railway subject. Thus, the integration of BIM into the rail industry is becoming a global trend [12]. Additionally, BIM contributes to construction planning and constructibility analysis, enabling efficient project scheduling and construction process planning [13]. With BIM, the on-site validation, guidance, and tracking of construction activities become more straightforward, leading to increased productivity and quality control [14,15]. [PERSON], [PERSON] et al. emphasized the cost savings and project outcome improvements that implementing BIM in railway construction projects in the design phase may bring [16]. Moreover, BIM has gained recognition in multiple railway construction projects. For instance, Taiwan High-Speed Rail Corporation, in which BIM technology was used in the construction of the Changhua Station [17] and the Honam High-Speed Railway Lot No. 4-2 in Korea [18] successfully applied BIM in railway infrastructure construction [19].  
These referenced studies delve into the application advantages of BIM in project construction, discussing how BIM supports the design, construction, and maintenance of railway construction projects, as well as how it yields economic benefits and cost savings. Integrating BIM into railway projects offers numerous advantages, including collaboration, time savings, cost optimization, conflict prevention in networks, facility management optimization, and enhanced engineering quality [12]. Leveraging BIM in railway construction projects empowers stakeholders to enhance decision-making processes, streamline project delivery, save costs, and enhance the overall efficiency of the industry [20].