NeTEx is undoubtedly large and quite complex, and uses a sophisticated model that has been evolved over more than fifteen years to cover the requirements of many different types of system – this imposes a significant learning curve, especially if you are unfamiliar with Transmodel, or with software engineering notations such as UML. However, it is also highly modular, so only the required modules need to be considered and once the core principles have been assimilated, the use of a consistent terminology and a uniform set of design patterns facilitates learning of new areas of functionality. The provision of reusable components such as calendar conditions, stops, etc also reduces the effort needed to understand the system.