The next figure gives the inclusion in the Trans European Transportation Networks Programme (TETN). Rail links which are included in this programme are coloured. Previously existing links are displayed in red, planned or links under construction are displayed in yellow whereas all other links which do not belong to the programme are displayed in black. The programme contains rail links for the EU member States. Both existing and planned links are taken from the "Joint Decision of the European Parliament and of the Council" and from the "TEN implementation report". For all the 'planned' links included in this programme additional information on the nature of the projects or constructions are available (e.g. new constructed conventional lines, upgraded high speed lines).

Altogether the following categories can be differentiated: High speed lines, upgraded high speed lines and conventional lines. High speed lines represent recently built or planned tracks for high-speed operation. These links are designed for a maximum speed generally equal or greater than 250 km/h, i.e. for average speeds between 150 and 250 km/h (depending on the country and on the technical system). Links upgraded for high speed are equipped for speeds up to 200 km/h, i.e. for average speeds between 100 and 150 km/h. All other links of the TETN outline plan fall in the conventional category.

Additionally to the TETN programme, the so-called TINA networks for the Candidate Countries as defined by the TINA-Secretariat are also included in the rail network database. Moreover, also the so-called 'Helsinki Corridors' (formely known as 'Crete Corridors', according to a decision of the Council at the meeting in Crete in 1995) in the remaining east European countries are included.