These TSIs define the essential requirements of the above-mentioned European directives for specific cases and define a set of technical requirements that apply to new subsystems put into service.
When the first TSIs were published, they still had separate legal bases: one for the interoperability of the high-speed rail system (European Community Directive 96/48/EC) and one for the interoperability of the conventional rail system (European Community Directive 2001/16/EC).
Once completed, they are submitted to the European Union Member States Committee for its opinion before being decided by the Commission.
They are then translated into the official Languages of the European Union before being notified to the Member States.
TSIs adopted as regulations by the commission are directly applicable by all.