This study uses a three-dimensional, compressible, turbulence model to investigate the pressure waves generated by two trains passing each other in a tunnel. The turbulent flow around the train bodies is computed by the RNG k-e turbulence model; a sliding mesh method is utilized to treat the moving boundary problem. The numerical results are verified through the results of laboratory experiment and field observation. Then, a series of numerical simulations are carried out to examine the influences of the tunnel length, the blockage ratio, the train speed and the intersecting location on the interactions of aerodynamic waves generated by the trains. The simulation results reveal that the pressure and drag coefficients of the trains reach a maximum when the two trains intersect at the mid-point of the tunnel and the values of pressure and drag coefficients increase as the train speed and the blockage ratio increase due to the train/tunnel interaction. However, the side force coefficient is dominated by the train/train interaction and its maximum value occurs when the two trains are aligned side by side.