HSL 1

{{Use dmy dates|date=January 2018}}

{{Infobox rail line

| box_width = auto

| name = HSL 1

| color =

| logo =

| logo_width =

| image = Thalys by Silly.jpg

| image_width = 321px

| caption = Thalys on HSL 1

| type = High-speed rail

| system = NMBS/SNCB

| status = Operational

| locale = Belgium

| start = LGV Nord at Fretin Junction

| end = {{stnlnk|Brussels-South}}

| stations = 1

| routes =

| daily_ridership =

| open = 1997

| close =

| owner = NMBS/SNCB

| operator = Eurostar
Thalys
TGV

| character =

| stock =

| linelength = {{convert|88|km|mi|abbr=on}}

| tracklength =

| tracks = Double track throughout + loops

| gauge = {{RailGauge|sg|allk=on}}

| load_gauge = UIC GC

| electrification = {{25 kV 50 Hz|conductor=overhead}}

| speed = {{convert|300|km/h|mph|0|abbr=on}}

| signalling = TVM-430

| elevation =

| map = {{HSL 1}}

| map_state =

}}

The HSL 1 ({{langx|nl|Hogesnelheidslijn 1}}, {{langx|en|High-Speed Line 1}}) is a high-speed rail line which connects Brussels, Belgium, with the LGV Nord at the Belgium–France border. It is {{cvt|88|km}} long with {{cvt|71|km}} of dedicated high-speed tracks and {{cvt|17|km}} of modernised lines. Service began on 14 December 1997.

The line has appreciably shortened journey times, the journey from Paris to Brussels now taking 1 hour 22 minutes. In combination with the LGV Nord, it has also impacted international journeys to other cities in France and to London, ensuring high-speed through-running by Eurostar, TGV, Thalys PBA and Thalys PBKA trainsets.

The total construction cost was €1.42 billion.{{Citation needed|date=February 2009}} The signalling system installed is the TVM-430 in-cab signalling system, the same as LGV Nord in France, and High Speed 1 in the UK.