Sittard to Liège train with Regional-Express

Intercity is a widely recognized brand for express train services that connect cities over longer distances, often with limited stops and comfortable carriages for long-distance travel. The term \Intercity\" originated in the United Kingdom in 1966 with British Rail's electrification of the West Coast Main Line, becoming a brand for their main-line passenger routes. Today, Intercity services vary across Europe, with some countries like Switzerland offering modern, high-standard trains, while in others, they may be older compared to newer high-speed options. Many European countries use \"InterCity\" as an official brand name for regular, long-distance train services meeting specific speed and comfort criteria. For example, PKP Intercity is a major Polish rail operator connecting cities and tourist resorts within Poland and across Europe. Trenitalia's Intercity trains in Italy offer an affordable and widespread means of rail transport, connecting various cities and towns. These trains typically offer Standard and First Class services, with amenities like power sockets and sometimes catering."

Regional-Express (RE, or REX in Austria) is a type of regional train service found in Germany, Luxembourg, and Austria. It functions as a semi-fast train, making fewer stops than a Regionalbahn or S-Bahn but more than an Intercity or Intercity Express. RE services typically reach top speeds of 160 km/h, with some reaching 200 km/h on high-speed lines. While initially operated by DB Regio, many lines are now run by various private operators. These trains often use double-deck cars with electric or diesel locomotives.