Characterization of Ballast Performance in Heavy Axle Loading (HAL) Shurpali, A.A., E. Van Dam, J.R. Edwards, D.A. Lange and C.P.L. Barkan. 2012. Characterization of Ballast Performance in Heavy Axle Loading (HAL). In: Proceedings of the American Railway Engineering and Maintenance-of-Way Association Annual Conference. Chicago, IL. Files We're sorry. At this time, we do not have a full text copy of this text available. Categories Infrastructure