Railway infrastructure requires the execution of various nonroutine interventions over time, such as major track renewals, infrastructure upgrades, and technological improvements, to ensure continued safety and meet evolving transportation demands. The full planning process for these interventions spans multiple departments and planning phases, yet no single unit or individual typically holds a complete ownership or visibility over the full process. This fragmented understanding hampers efforts to improve planning efficiency and effectiveness, as innovation efforts targeting isolated planning phases or tasks often overlook their temporal and functional interdependencies. Tasks may rely on inputs from upstream tasks, must deliver outputs to downstream tasks, and are often initiated years in advance of intervention execution. This work provides a detailed description and discussion of the nonroutine intervention planning process within a Swiss railway organization. Using Business Process Model and Notation (BPMN) 2.0, the process is modeled across several key phases, including (1) network development; (2) development intervention planning; (3) maintenance intervention planning; (4) network coordination; (5) production planning; (6) project planning; and (7) capacity planning. The findings highlight the challenges in improving the planning process in railway organizations and point out several ways that research could be focused to improve the process that are best identified when understanding the full process. The areas of research identified are efforts to improve (1) integrated planning and process alignment; (2) process transparency and ownership; (3) interdisciplinary coordination and communication; and (4) decision support through operations research, machine learning, and digital tools such as building information modeling and geographic information systems. Beyond these identified areas of research, the described planning process is unique in its level of detail and, to the best of our knowledge, the first of its kind in the published literature, and it offers a foundational reference for academic research and practical improvement initiatives in similar contexts.
Chuo et al. (Sat,) studied this question.