Asbestos on railway ballast: analyses, monitoring and management

The material for rail ballast is normally obtained from the crushing of rocks with high mechanical strength, such as basalt, trachyte, gneiss and "green rocks", as ophiolites (serpentinites, amphibolites, gabbros, prasinites, etc.). Green rocks often contain discrete quantities of heavy metals and asbestos-like minerals, as chrysotile and amphibole asbestos. In Italy, the chrysotile asbestos mine in Balangero (Turin) has produced railroad ballast, over 5 million of tons, which was used for the railways of Piedmont, Liguria, Lombardy and, partially, Tuscany and, partially, Emilia Romagna, from 1930s up to 1990. In addition to Balangero, several other serpentinite quarries provided the railways ballast from the 1940s to 2000. As a result, many railway lines are now contaminated with significant quantities of asbestos. Since 2005 it was started a very complex and ambitious monitoring project alongside the Rete Ferroviaria Italiana - Italian Railway Network S.p.A. in order to detect the exact contours of the problem and to find the most appropriate methods to solve it.