 Trains draw current from two sets of 750-volt direct current guide bar/third rails on either side of each motor car.Nine-car trains draw large currents of up to 6,000 amperes, requiring that all models of rolling stock have calibrated traction motor control systems to prevent power surges, arcing and breaker tripping.Both models have electrical braking (using motors) to assist primary friction braking, reducing the need to replace the brake pads.