More difficulties are facing the growing number of railway projects in different parts of the world, as well as, other big capital investment projects. Organizations and researchers are searching for methods to improve the performance in terms of cost, time, and quality. One of the identified key areas of improvement is interface management. This work tries to establish a clear link between IM and project management, by exploring various common areas, such as the body of knowledge, and roles and responsibilities. Then it goes a step further by creating a complete Project Interfaces Management (PIM) Process, that includes six sub-processes based on the Plan-Do-Check-Act cycle. This work is built upon actual railway project documentation prepared by leading organizations in the industry, and inspired by the structure of the PMBOK® Guide published by the Project Management Institute in 2008. These two characteristics will enable this process first to communicate with project management processes and to be further applied in the wider range of construction projects. This work will add up to the IM body of knowledge and is meant to be considered as a guide to IM common practices.