The track is laid on the basis of an imaginary three-dimensional line, both horizontally and vertically. Track geometrics indicates the maximum allowed deflection of curves and the gradient of slopes on the route. These must meet certain requirements to guarantee safety and travelling comfort. If the angle is too sharp, a high speed train could leave the track, or passengers would be pressed into the carriage wall. This is prevented by making very slight curves.

On the HSL route, the high speed trains will be able to travel at 300kp/h in a number of places, such as between Hoofddorp and Rotterdam. Here, the curves must be extremely slight. The sharpest curve on the route is at Rijpwetering. Here, the curve has a so-called curve radius of 4250 metres. On this section of the track, the trains will move at appropriate speed.

The maximum slope of viaducts, fly-overs, the Hollandsch Diep bridge and the tunnel access ramps are 2,5 percent, in other words, 1 metre vertical to 40 metres horizontal.