Performance of T-shape and Y-shape inclined noise barriers in railway noise mitigation is studied in this paper. Control of the noise attenuation and sound-map behind two conventional barriers is performed by optimal adjusting their inclination angle. Logarithmic averaging of the noise attenuation in different heights is adopted to be the objective function. A numerical model is constructed and the Steepest Descent Method (SDM) is adopted as the optimization algorithm. Validly of the modeling and solution procedure is verified by use of experimental results. Field measurements are performed and the frequency responses of different trains are loaded into the model. Optimal inclination angel is subsequently obtained for each configuration. It is found that the inclination angle can play a significant role in noise mitigation level remarkably in high elevation back regions.