Abstract: A compacted cutting powertrain consisting of multiple motors,a torque coupled gear train and a planetary gear train was proposed to avoid the influence of longwall shearers’ ranging arm deformation. Dynamic behavior of the torque coupled gear train affects the load carrying capacity and service life of the powertrain. Causes of inconsistent fluctuant input speeds in the torque coupled gear train were analyzed. Effects of the inconsistent input speeds on the dynamic behavior of the gear train were studied through simulating. Manufacturing and assembly errors in the power- train and different responses from multiple motors can cause inconsistent fluctuant input speeds. Inconsistent fluctuant input speeds make the dynamic meshing forces in the torque coupled gear train to fluctuate. The phase of the dynamic meshing force of each transmission path is different from each other. The inconsistent input speeds also affect the pin- ion vibration acceleration in the torque coupled gear train. When the inconsistent degree of input speeds increases from 0 to 0. 005,the tangential and radial vibration accelerations increase by 11. 89 and 7. 07 m / s2 ,respectively. The in- consistent input speeds have a greater impact on the tangential vibration acceleration. Some dynamic behaviors of the torque coupled gear train were verified by an experiment. There exist inconsistent fluctuant input speeds in the gear train. Features of the input shaft vibration acceleration acquired by the experiment are similar with those acquired by simulation in the time and frequency domains.