The HSL 2 is a Belgian high-speed rail line between Leuven and Ans and is 66.2 km (41 mi) long, all of it on dedicated high-speed tracks, which began service on 15 December 2002. As part of the Belgian railway network, it is owned, technically operated and maintained by Infrabel.

Thalys was a brand name used for high-speed train services between Paris Gare du Nord via Brussels-South to either Amsterdam Centraal or to German cities in the Rhein-Ruhr, including Aachen, Cologne, Düsseldorf, Duisburg, Essen and Dortmund. Since 29 September 2023, the services operate under the Eurostar name; sometimes referred to as Eurostar Red, based on the colour of the trains.