The European Union Agency for Railways (ERA) is the agency of the European Union (EU) that sets mandatory requirements for European railways and manufacturers in the form of Technical Specifications for Interoperability, which apply to the Trans-European Rail system. The ERA publishes a document summarising the status of the TSIs. The ERA sets common safety targets, common safety methods and common safety indicators, following Directive 2004/49/EC and amendments. The ERA also hosts a number of databases, among which a register of remaining, applicable national rules.