Ballast projection is one of the central challenges in high-speed operations, particularly at speeds above 300 km/h. It occurs when air turbulences generated beneath the train stir up ballast stones and project them in an uncontrolled manner, posing a significant safety risk.

The aerodynamic sleeper developed by ADIF (and other leading stakeholders) aims to minimize this risk through an optimized flow concept while simultaneously improving ride quality and operational safety in high-speed traffic. The rounded mid-section shape of the sleepers ensures an even distribution of airflow beneath the train, significantly reducing ballast projection. This enables higher operating speeds with increased safety.

\nRAILONE's Spanish subsidiary TRAVIPOS received approval for manufacturing in close cooperation with ADIF. The modified design is registered in ADIF's validated products register, thereby enabling series production of the sleeper.