Mayank Dhingra
The National Automotive Test Track Facility, or NATRAX, opened its 11.3 km-long high-speed track (HST) on June 29, which is one of the most advanced test tracks in the world.
- 2 km long straight line with zero longitudinal gradient
- 1,000m bank helps maintain speeds exceeding 250kph
- Tarmac’s hybrid material allows high-speed testing
The site is located in the outskirts of Indore in Pithampur, Madhya Pradesh, India. It aims to support the Indian automotive industry and allow it to perform various tests (such as acceleration, high-speed stability, turning balance, durability) to test and develop new cars and even real ones. The world’s fuel efficiency test.
However, the most impressive thing is the way the track is built, focusing on the smallest details of design and construction to achieve a truly high level of infrastructure skills. IDIADA, a Spanish design and testing agency, is behind the preliminary design and master planning of HST.
After setting India’s first 0-300kph lap time on this world-class facility, we have a deep understanding of the technical details behind this architectural marvel:
Apron
HST mixes different materials, including bitumen and polymer modified bitumen, to provide a silky smooth surface for high-speed vehicle testing. The material combination in sharp contrast to the concrete structure was achieved in an iterative manner by considering the high ambient temperature and longevity of Madhya Pradesh.
The theoretical life of this track can be as long as 25 years, but if a very high usage rate is observed, it will be re-paved every 10 years.
Zero gradient
This 2 km long arrow straight section is absolutely level with the ground, the longitudinal slope is zero, and the surface regularity and uniformity reach the tolerance level of plus/minus 3mm.
Such strict specifications require a lot of engineering brainstorming. When the height difference between one end of the track and the other end is 20 meters, the architect had to dig a depth of up to 13 meters on one side of the curve and build the other end. A 7-meter high embankment to meet the zero slope goal.
1,000m radius, shallows
Another unique feature of HST is the parabola with a radius of 1,000 meters, designed to allow drivers to maintain speeds of up to 250 km/h or more. Unlike most proving grounds in the world, this part of the NATRAX circuit has an extremely shallow slope, allowing drivers to drive with confidence without losing control in the middle of a curve.
Transition curve
Connecting the 2km-long straight road with the parabola or semicircular curve is a transition zone or transition curve, which gradually connects the two so that the driver can continue to maintain high speed and seamlessly transition without any bumps or mid-angles. Bumpy.
The project that has been deployed is the sinusoidal transition method, which gradually changes in all three dimensions to provide a more seamless roll angle change, thereby minimizing the lateral and vertical shocks felt inside the vehicle during the transition.
The 11.3 km long track provides space for a longer transition zone, allowing the use of a sinusoidal transition curve instead of the traditional cyclotron curve method, which is less seamless and is mainly used for shorter test tracks.
Efficient drainage
Water is the natural enemy of asphalt, especially on the 13-meter-deep section of the track, the possibility of water accumulation under heavy rain is very high. However, in order to effectively solve this problem, the high-speed rail has adopted special design measures, a total of four lanes are drained, two lanes are on the ground, and two lanes are on both sides of the sidewalk and the service road.
In addition, in the 13-meter cut section, the drainage depth can be up to 3 meters to collect more water. RITES, a national public sector company, has designed drainage and cross-drainage for the facility.
