In many densely populated areas, capacity increases in the railway network are necessary. However, space for additional tracks is limited. Therefore, increasing capacity of the existing network is a major goal of railway companies and politics. The railway control, command, and signalling (CCS) technology has an important impact on capacity. One of the major functions of the CCS is the assignment of track infrastructure to trains in nodes (route assignment). To maintain safety, the interlocking system blocks the assigned infrastructure so that it cannot be used by other trains. In order to maximise capacity, the safety-related minimum duration as well as the minimum spatial extension of the assignment should be as small as possible. Today, the interlocking systems usually use predefined, fixed train routes. As a result, often more track infrastructure is assigned to a train than necessary for a longer duration than required. For a long time, the preconditions for dynamic route assignment such as a precise localisation and a continuous communication between trackside CCS and the trains were not given. Emerging CCS technologies change this circumstance, so it seems reasonable to examine how an interlocking system that supports dynamic route assignment could contribute to the goal of increasing capacity. For this purpose, the article identifies requirements for the operating principles of such an interlocking and illustrates the capacity benefits of the dynamic route assignment approach with the aid of specific operational scenarios.