Track curvature

In order to run at very high speeds, HSR trains need to be far more powerful than conventional trains. They can accelerate at a much quicker pace reaching 100kphin less than 500m or 300kph from a standing start in just over 7km.

They are also capable of climbing steeper gradients, which allows them to ‘hug’ the landscape - avoiding the need for so many viaducts and high embankments and minimising noise and environmental impacts.

However, in order to maintain their top speeds, the lines that they travel on must be built with the fewest possible curves – and where curves are unavoidable, they must use larger turning circles to change direction. As you would expect, braking distances must also be longer to allow the trains to slow down safely.

Table 2 shows how high speed rail specifications compare with those of conventional rail travelling at a top speed of 200kph.

Table 2

	Classic	HS Rail
Top speed (kph)	200	400
Installed power (MW)	4	20
Maximum gradient incline (%)	1	3
Minimum radius of curvature (m)	1800	7200
Average braking distance (m)	2000	*5500

*Based upon an estimated speed of 350kph on a level gradient.