Ballast (railroad track) 1 Ballast settlement 1 Compaction 1 Cyclic loads 1 Deterioration 1 Linear lattices Non linear 1 Non-linear lattice, support stiffness variation 1 Railroad tracks 1 Railroads 1 Stiffness 1 Stiffness variations 1 Track degradation 1 Track degradation, Ballast settlement, Transition, Non-linear lattice, Support stiffness variation 1 Track degradation, ballast settlement, transition, non-linear lattice, support stiffness variation 1 non-linear lattice, support stiffness variation 1