This report gives advice on how to choose the most suitable method for bridge and track replacement activities on operational railway networks. It will assist IMs in the evaluation of, and selection from, the wide range of possible replacement methods presented in the previous deliverables from WP3: ML D3.1 (2013) Benchmark; ML D3.2 (2014) Bridges and ML D3.3 (2014) Track.An important consideration in replacing elderly infrastructure within the railway environment is track access since this is the major source of income for railway administrations and can be an important factor in national economics. Consequently it is important to reduce any downtime period by planning and optimizing the construction processes, even though this may lead to somewhat increased investment in terms of labour, temporary solutions and machinery. Here a systematic approach, which should always be connected to life cycle assessment, is extremely important. Hence, the focus of this report is on cost effective and environmentally sound methods that are easy to implement with a low impact on rail traffic through short network down time that will help the IM to decide on the most favourable measures based on technical, social, environmental or cost demands.First the planning process is treated in chapter 4 and Appendix A. Then guidelines are given on bridge replacement in chapter 5 and some examples of standard bridges are presented in Appendix B. Track, Switches and Crossings are presented in Chapter 6. The report also presents a proposal for a rough estimation of track possession costs and related parameters which can be used where no formal method of calculation is used in Appendix C.