Three-bay linear grillage – BL model of longitudinal wave transmission (source subsystem: L1): comparison of FEM (uniform material properties), FEM (random Young’s modulus) and ASEA. FEM (random Young’s modulus) with Euler-Bernoulli elements; FEM (uniform material properties) with Euler-Bernoulli elements; FEM (random Young’s modulus) with Timoshenko elements; FEM (uniform material properties) with Timoshenko elements; ASEA (Euler-Bernoulli group velocity); ASEA (Timoshenko group velocity). Results from FEM are shown with 95% confidence intervals.