With increase in the use of railway transport, ensuring robustness in railway timetables has never been this important. In a dense railway timetable even a small disturbance can propagate easily and aect trains' arrival and departure times. In a robust timetable small delays are absorbed and knock-on eects are prevented eectively.The aim of this thesis is to study how optimization tools can support the generation of robust railway trac timetables. We address two Train Timetabling Problems (TTP) and for both problems we apply Mixed Integer Linear Programming (MILP) to solve them from network management perspectives. The rst problem is how robustness in a given timetable can be assessed and ensured. To tackle this problem, a headway-based method is introduced. The proposed method is implemented in real timetables and evaluated from performance perspectives. Furthermore, the impact of the proposed method on capacity utilization, heterogeneity and the speed of trains, is monitored.Results show that the proposed method can improve robustness without imposing major changes in timetables. The second problem addressed in the thesis is how robustness can be assessed and maintained in a given timetable when allocating additional trac and maintenance slots. Dierent insertion strategies are studied and their consequences on capacity utilization and on the properties of the timetables are analyzed. Two dierent insertion strategies are considered: i) simultaneous and ii) stepwise insertion. The results show that inserting the additional trains simultaneously usually results in generating more optimal solutions. However, solving this type of problem is computationally challenging. We also observed that the existing robustness metrics cannot capture the essential properties of having more robust timetables. Therefore we proposed measuring Channel Width, Channel Width Forward, Channel Width Behind and Track Switching. This thesis contains three papers which are appended. The results of this thesis are of special interests for railway trac planners and it would support their working process. However, railway trac operators and passengers also benet from this study.iii