While in China they are already thinking about trains that reach 4,000 km/hIn Spain we are looking for an AVE that reaches 350 km/h that could be reached without problems if it were not for one detail: the tracks. And for something much more specific: the sleepers. The solution is a new design called “aerotraviesa” that will increase the speed of the BIRD.
The problem is that theory is one thing, and practice another.
a physical problem. Spain plays in the high speed major league and, in it, Renfe opera four types of trains. The Alvia and Avant reach 250 km/h. The Avlo and the AVE reach 300 km/h. However, the machines are prepared to reach higher speeds, the aforementioned 350 km/h. The problem is in physics. When a train exceeds a certain speed, 300 km/h, a phenomenon called ‘ballast flight’ occurs.
This implies that the underside of the train generates turbulence that creates areas of low pressure on the track. This causes the passage of the train to vibrate the stones, the ballast, lifting them and causing them to collide against the underside of the train or settle on the tracks and sleepers themselves. Furthermore, at more than 300 km/h, the possible bumps on the journey increase.
Air traverses. That’s where a new sleeper design comes into play that the company itself Adif presented a few years ago. Instead of a flat crossbar, a traditional rectangle, the central part of it has a more rounded design.
Adif affirms This modifies the velocity field on the ballast in the area between the sleepers, minimizing the presence of ballast particles, and the key points are:
- Reduces 21% of the aerodynamic load in the space immediately above the ballast bed.
- The design allows increasing the distance between the ballast level and the upper face of the sleeper.
- It has no higher manufacturing or handling costs (they are still molds).
- And most importantly: the aerodynamic load generated by a train at 330 km/h on a track with current sleepers is equivalent to that generated by the same train at 370 km/h, but with aero sleepers.
AV350 Plan. In short, the aerocrossers improve the aerodynamic performance of the infrastructure and there is another important fact: their use allows an increase of 12% in the operating speed of the train. And it is not just theory, since Spain wants to start installing overhead traverses to improve the speed of the AVE. A few weeks ago, Óscar Puente, Minister of Transport and Sustainable Mobility, advertisement that the Madrid-Barcelona line will be the first to have these overhead traverses.
The result? Reach the maximum speed of the original design of the infrastructure, which is 350 km/h. Currently, the AVE reaches those 300 km/h due to the physical limitations mentioned above. This will allow us to go from the two hours and 37 minutes of the AVE that currently takes the least time to less than two hours.
Puente highlighted that the design of the aerocrosses is pioneer in the world. The Polytechnic University of Madrid, Adif and SENER constituted a consortium to develop this technology and obtained the patent in March 2014, achieving international protection in Europe, Saudi Arabia and the United States. There are countries that have faced the ballast problem in other ways, Germany covering the ballast with concrete, for example.
Arching an eyebrow. Increasing the speed of the train by changing the sleepers sounds great. The problem is that there are some aspects to consider. On the one hand, the cost-benefit debate not only because of what the investment will mean in changing all the sleepers, but also because of the maintenance of certain train materials that will suffer more than now.
Driving at 350 km/h exponentially increases the wear of both the wheels and the catenary, regardless of whether the ballast causes no damage to the train, or causes less. On the other hand, not only the sleepers come into play, but also the own land. A bump at 300 km/h can be annoying, at 350 km/h it can be something more.
Or two. And, beyond whether it is worth the investment to gain half an hour or what will happen with those possible technical problems, the big question is what happens with the rest of Spain. It is estimated that the Madrid-Barcelona section in which these air crossings begin to be applied will take about two years to complete. At a rate of 800 sleepers changed per day and 1,666 sleepers per kilometer, the work is of great magnitude.
And it is clear that it is a congested route and that it is seeing a boom in the number of travelers, but while that line is reinforced, the connection with other parts of the peninsula remains neglectedlike the train to Soria, Teruel or the perennial case of Extremadura.
Images | Xataka, Adif
GIPHY App Key not set. Please check settings