Impact Analysis of Railway Projects in a Flexibility Perspective

<title>Abstract</title> In a multiple case study, using both quantitative and qualitative data, the traffic impact of four Norwegian railway investment projects was analysed, focusing on the development of punctuality, frequency, travel time, number of travellers and construction cost. Front‐end ex‐ante predictions are compared with observed ex‐post outcome. Key success criteria for realization of planned benefits in the studied railway investment projects have been a combination of infrastructure development and acceptance for timetable adjustments. Investments that are executed in a large‐scale continuous construction process appear to be more likely to achieve such acceptance compared with investments built and decided upon section by section. Of the studied projects, section‐by‐section commitment to investments provided a better cost control than what was the case for continuous construction projects. In addition, this study points to challenges in realizing travel time reductions in a system with a combination of single tracks and high capacity utilization of double tracks. It is advised to clarify in appraisal documentation that benefits related to railway infrastructure investments are depending on appropriate timetable adjustments. The results indicate that a flexibility option (to sequence a decision process) may actually reduce the benefit potential of an investment.