Most railways constructed today in Brazil and across the world are built on a ballast layer, which is usually comprised of granular materials of rocky origin. Ballast is a very important element in the absorption of vertical stresses caused by train traffic and it has, among other roles, the function of ensuring the vertical and longitudinal alignment of the track and drainage of water. Being the top layer of the track foundation, ballast is constantly subject to mechanical deterioration, weathering and to action of other external agents. Problems stemming from ballast degradation impact both cargo and passenger traffic, resulting in costly track maintenance routines and causing operational inconveniences, in addition to facilitating the occurrence of accidents. In that context, the objective of this study is to assess the characteristics of different rocky materials used as railway ballast in the main cargo exportation and passenger corridors in Brazil, particularly regarding their resistance to wear. Results from several studies conducted in different parts of the country were assembled and compared. Simultaneously, tests were carried out on a sample of ballast material collected at an important rail corridor near Campinas, south-east Brazil, and its Los Angeles abrasion, shape evaluation, specific density, and water absorption indexes were obtained. Results retrieved from previous studies and from the original tests were all compared to international standards enforced in Australia, USA and Brazil, countries where heavy-haul cargo is most relevant. It was possible to notice that, in spite of Brazil having and using rocky aggregates from very diverse geological origins, being the continent-sized country that it is, they meet most international standards and recommendations regarding resistance to wear, according to the indexes analysed in this research. It could also be observed that the studied diabase is adequate for use as ballast material.

railway ballast, ballasted track, ballast abrasion, ballast properties