Principal Factors Contributing to Heavy Haul Freight Train Safety Improvements in North America: A Quantitative Analysis Wang, B.Z., C.P.L. Barkan and M.R. Saat. 2017. Principal Factors Contributing to Heavy Haul Freight Train Safety Improvements in North America: A Quantitative Analysis. In: Proceedings of the 11th International Heavy Haul Association Conference. Cape Town, South Africa. Files Principal Factors Contributing to Heavy Haul Freight Train Safety Improvements in North America: A Quantitative Analysis - Full Text (PDF) Categories Infrastructure