Abstract: How to predict the vibration/comfortableness characteristics of an express train(motor coach train) in China in its design was investigated. With the software ANSYS used to develop a finite element model for a motor coach, the frequency domain method is introduced to deal with the power spectrum density in MATLAB. Then, taking the horizontal irregularity of railroad as an example, a transient analysis is made to simulate the response from the running motor coach train with the acceleration responses collected at some nodes on a coach floor to calculate the degree of comfortableness and the coach's jolt-proof index. This method makes it possible to evaluate effectively the vibration characteristics and passengers' sitting comfortableness of a motor coach hence the whole train under different running conditions in the conceptual design.