To investigate the vibration analysis of elastically connected multiple beam system (ECMB) under the moving oscillator, finite sine-Fourier transform has been applied to the dynamic partial differential equations of ECMB with respect to space coordinates. en, the numerical integration has been used to solve the equations. Finally, the expression for vibration analysis of ECMB under the moving oscillator has been derived based on finite sine-Fourier inverse transform. Using the method developed in this study and ANSYS numerical method, the vibration analysis of a four-layer beam system under moving oscillator with different speeds has been calculated. e results show that the calculated results from the method developed in this study are in good agreement with the ANSYS numerical calculation results, and the differences between the two calculation results are all less than 2%, which verified the correctness of the method developed in this study. e method developed in this study has been applied to the beamrail system on a railway line in China. e effect of the train speed and interlayer stiffness on the vibration of beam-rail system has been investigated. e results show that the maximum dynamic deflection of the rail under the train load is always near the midspan, while the maximum dynamic deflections of the track plate, base plate, and bridge occur after the train travel through the midspan. e interlayer stiffness has a larger impact on the vibration of the rail and the track plate and little impact on the vibration of the base plate and the bridge.