This was part of the design behind the N700 bullet trains of Japan. They have motors in all trains in order to distribute weight and thus braking and accelerati

This was part of the design behind the N700 bullet trains of Japan. They have motors in all trains in order to distribute weight and thus braking and acceleration ability evenly across the whole train. It reduces wear on all wheels and components but as you mentioned adds complexity in the overall aparatus. They brake at stations using mechanical brakes though if I am not mistaken, the sound is pretty hard to ignore!