Its speed is considerably faster than regional trains at the same level, as it does not stop at all stations served by the regional trains. Nonetheless, it is slightly slower than InterRegio trains. Swiss Federal Railways describes the trains as ones that serve "rapidly into the regions".
Until the late 2004 timetable overhaul, the RegioExpress was limited in circulation. One of the main lines which ran as a RegioExpress line (abbreviation: RX) was the Rheintal Express, from St. Gallen through Sargans to Chur (the other was the CityVogel from Zurich to Konstanz). As of the late 2004 timetable overhaul, the RegioExpress was introduced as faster Regio (formerly regional) trains, and the term was thrown into expanded usage. The abbreviation was changed to RE instead of the previous RX.