Similarly, the solution to the rail displacement forthe alignment irregularity (Figure 1(b)) and half sinusoidal deformation (Figure 1(c)) can be obtained.For the rail displacement caused by arbitrary bridgedeformation such as the foundation settlement (Figure1(e)) and several angular rotations (Figure 1(d)), theanalytical solution is too complicated. In these cases,the rail displacement can be found by minimizing theenergy in the track system