Treatment and recovery of contaminated railway ballast

In the last decade several cases of railway ballast contamination by heavy metals from lubricants, track corrosion and wear, and welding residues were observed. In this paper experiments of metals extraction from stones commonly found in Italian railway ballasts are presented. The stones were sampled from an operating railway, or procured from suppliers and artificially contaminated. Metals extraction was performed by washing with aqueous solutions of EDTA, and the effectiveness of the remediation process was evaluated through leaching tests. Finally, a process for the implementation of this technique on the maintenance train used to replace the ballasts is proposed.