This paper proposes an innovative macroscopic timetabling model aiming to optimize railway infrastructure to accommodate the future increasing demand. The model applies the PESP formulation to railway operations and formulates it as a MILP model. The number of tracks on each portion of the infrastructure is flexible, and so are the conflicts between different trains. The model minimizes the overall construction and operation costs while ensuring a conflict-free timetable for the long-term demand. A case study on the Swedish Mälarbanan line demonstrates the model’s application and validates the microscopic feasibility of the produced timetables. Model shows promising results by suggesting low infrastructure upgrades while offering total travel times almost equivalent to the case where the entire line is upgraded.