The EU is slowly realising its vision of a united, interoperable railway system represented through the Trans-European Transport Network (TEN-T). One initiative to further this objective has been the EU-funded project 'Electromagnetic compatibility between rolling stock and rail-infrastructure encouraging European interoperability' (Railcom). The project worked on harmonising interference limits for TEN-T train detection systems and regulating the railway electromagnetic environment for communication and monitoring. Railcom examined the link between operation and electromagnetic emissions to evaluate and predict interference with communication systems. Overcoming national barriers and laws, Railcom conducted intensive modelling and testing in order to elaborate harmonised calculation methods that yield a unified set of interference limits in train detection systems. Based on testing conducted in the Netherlands and Switzerland, including existing measurements from other EU countries, the project collated data about line voltage and current over many days. It used computer technology connected to an electromagnetic measurement system in order to map interference frequencies, resulting in a probability distribution of voltages and currents per frequency. From this, Railcom produced a toolbox of valid methods to characterise train detection systems over and under the train. It concluded that results are strongly influenced by antenna characteristics. This deduction and several others led the project team to elaborate a set of recommendations and standards that were disseminated to stakeholders through journals and conferences. Thanks to Railcom and other similar EU initiatives, railway interoperability is already a reality that is steadily spreading across the TEN-T in different European regions.