Built on the HSL 3 line of the Belgian TGV service for Brussels-Liège-Cologne, the tunnel was completed in 2004.

[3] The tunnel links the Liège conurbation with the Herve plateau at a depth of 120 metres (390 ft).

The bored section is 5,940 metres (6,500 yd), extended by covered sections of respectively 177 and 388 m. Dozens of geological layers of differing hardness had to be tunnelled through, lime layers needing to be blasted through with dynamite.

The tunnel reaches a depth of 127 m in some areas; it has an average ramp height of 1.7%, with a maximum of 2% at the entrance in Soumagne.

The free space profile in the tunnel is approximately 69 m2 (740 sq ft), which restricts speeds to 200 km/h (120 mph).