## 3 Research Methodology  
According to [27], there are three conditions that determine the research strategy: the form of the research question (RQ), control over the events being researched, and focus on contemporary events (Contemporary/historical events). A research strategy was established for each research question in this study. For the RQ1 research process, the methodology is based on a literature review, archival analysis, and historical data from case studies. Subsequently, expert validation is performed by qualitative analysis utilizing the Delphi method and focus-group discussions (FGDs). This research method is to identify the indicators associated with the reasons for delays in the completion of the Railway Station Phase II Construction Projects. Meanwhile, to answer RQ2, a literature review, archival analysis, and historical data examination were conducted. Additionally, qualitative analysis encompassing the pre-risk mitigation phase was performed throughout the focus group-discussion phase. Finally, to answer RQ3, PERT techniques and Monte Carlo Simulation with @Risk Software from Lumivero for quantitative analysis were established to create a simulation for scheduling the implementation of Phase II of the Railway Station Development Project, encompassing both post-risk mitigation phases.  
The Critical Path Method (CPM) quantitative analysis regarding essential scheduling activities for RQ2 and RQ3 was conducted utilizing archive data from a case study involving MS Project V2016 software. The calculated values from RQ2 and RQ3 will be treated as inputs to estimate the total duration, which is calculated using MS Project by entering the calculated PERT values, theoretical values, and simulated values. Those three types of values are compared, and deviations with the initial baseline based on the contract are also calculated. The calculation is performed based on 22 of the initial 51 risk factors for railway project delays, derived from various literature surveys and research findings from the previous research results [7]. The qualitative analysis is employed to validate the data of 51 variables related to railway project delay risk, where 22 risks were validated, while the rest were eliminated due to insignificance of the delay, as per the findings of that study. Furthermore, confidence levels (\(\alpha\)) of 80%, 90%, and 95% are suggested according to various previous studies, delineating the confidence level (\(\alpha\)) value and the number of iterations from various literature reviews on railway project delays [6; 13; 28; 29]. This study differentiated the confidence level (\(\alpha\)) according to theoretical and simulated values. This study also suggested 10000 iterations in order to have much better results.  
The criteria for survey respondent profiles are essential for guaranteeing the reliability and validity of survey outcomes. These criteria include several elements, such as demographic attributes, recruitment techniques, and response behaviors, which collectively influence the quality of the obtained data. The respondent experts consist of five individuals who are both physically and mentally healthy; possess at least a bachelor's degree in civil engineering; and have academic or practical experience in railways and the construction of buildings, bridges, or railway operations facilities, with a minimum of ten years of relevant work experience. Five respondents were selected: four of them are from contractors, and one of them is an academic, with experience ranging from 18 to 37 years.