Liège to Roermond train with Regional

NS International, a subsidiary of the Dutch state-owned railway Nederlandse Spoorwegen (NS), operates international intercity and high-speed connections to various European cities, including Brussels. The "IC Brussel" refers to their Intercity service connecting the Netherlands and Belgium. These trains offer a direct and comfortable way to travel between major cities like Amsterdam and Brussels. As of late 2024, NS International, in collaboration with the Belgian railway company SNCB, is introducing new Intercity New Generation (ICNG) trains on the Brussels-Amsterdam route. These new trains are faster, reaching speeds of up to 200 km/h, and offer amenities like onboard Wi-Fi and power sockets. They aim to significantly reduce travel times and increase the frequency of services between the two countries.

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.

The term "Regional" can refer to different train companies and services depending on the country. In Germany, "Regionalbahn" (RB) is a type of local passenger train that typically stops at all stations on a given line, connecting cities to their surrounding areas. Many RB trains are operated by DB Regio, a division of Deutsche Bahn, but other companies also run these services.