The HSL 4 (, , ) is a Belgian high-speed rail line part of the 87 kilometres (54 miles) axis which connects Antwerp to the Dutch border. It is 40 kilometres long (24 miles); 36 kilometres (22 miles) of it being dedicated high speed tracks. It was scheduled for completion by 2005 and opened in 2009. Together with the HSL 1 to the French border and HSL-Zuid to Amsterdam, the line has shortened journeys between Brussels, Paris and the Netherlands. HSL 4 is used by Thalys, Eurostar e320, and Intercity Direct. It was formerly used by fast internal InterCity trains (Class 13 locomotives with I11 vehicles) and by Fyra, both of which were replaced by the Intercity Direct services. Route The high-speed HSL 4 begins just north of Antwerp (near Luchtbal), and runs 36 km where it meets the Dutch border. From Brussels to Antwerp Though HSL4 begins in Antwerp, it is part of a Paris-Brussels-Amsterdam corridor. High speed trains like Thalys, upon departing Brussels for Amsterdam, first use the existing, conventional track, electrified at 3 kV DC. From Brussels South station, trains travel northwards through the Brussels-Central and Brussels-North stations. At Schaarbeek the line splits in two; the eastern branch continues to Liège and the German border, the northern branch towards Antwerp and the Dutch border. Between Brussels and Antwerp (47 kilometres), trains travel at 160 kilometres per hour on line 25N and then the upgraded existing line 25 (with the exception of a few segments where a speed limit of 100–120 km/h is imposed). From Antwerp north In Antwerp, a tunnel has been constructed underneath the city to permit high-speed trains to run directly through Antwerpen-Centraal to the new high-speed line north, an extension of line 25 until Antwerpen-Luchtbal railway station, after which line 4 (HSL 4) starts. Trains enter the 1.5-kilometre long, two-tube tunnel past Berchem at 90 kilometres per hour. They exit the tunnel at 40 km/hour, it seems due to stability and infiltration concerns. The line surfaces at Antwerpen-Dam as line 25, and after crossing the Albert Canal, crosses the existing Antwerp-Essen line at 120 km/h. At the E19/A12 motorway junction, trains leave the regular line to run on new dedicated high-speed tracks to the Dutch border (40 kilometres away) at up to 300 kilometres per hour. The route parallels the E19 motorway until the border, which has required the building of several bridges. The