The HSL-Zuid (Dutch: Hogesnelheidslijn Zuid, lit. 'South High-Speed Line') is a 125-kilometre (78 mi) high-speed railway in the Netherlands running from the Amsterdam metropolitan area to the Belgian border, with connections to conventional railways to Breda and The Hague. Together with Belgium's HSL 4, it forms the Schiphol–Antwerp high-speed railway. The line allows speeds of up to 300 kilometres per hour (190 mph) and is used by both domestic and international services.
Initially planned to open in 2007, the HSL-Zuid entered public service on 7 September 2009. It is utilized by Intercity Direct and Eurostar trains, providing fast connections between cities such as Amsterdam, Rotterdam, Brussels, Paris, and London. Although designed for high-speed travel, short sections near Rotterdam and Antwerp require trains to reduce speed due to conventional infrastructure. The line uses the 25 kV 50 Hz AC electrification systems common to most northern European corridors along with European Train Control System signaling.