HSL 4 is used by Thalys, Eurostar e320, and Intercity Direct, as well as (on weekdays only) by local and peak hour trains terminating at Noorderkempen railway station.

High speed trains like Thalys, upon departing Brussels for Amsterdam, first use the existing, conventional track, electrified at 3 kV DC.

The line passes through Schoten, Brasschaat, Brecht, Wuustwezel, and Hoogstraten, before crossing the border into the Netherlands and connecting to the Dutch HSL-Zuid.

A tunnel has been constructed to permit the passage of trains under the city, additionally creating a subterranean junction between Antwerpen-Berchem and Antwerpen-Dam railway station [nl; fr; de], passing through Antwerpen-Centraal.

The above-ground tunnel Peerdsbos is comparable to an avalanche gallery except instead of snow it protects the trains from falling trees and the highway traffic on the E19.