In a four track system, which track carries the step chain axle?

In a four track system, the uppermost track is specifically designed to accommodate the step chain axle. The step chain axles play a critical role in guiding the movement of the steps as the escalator operates. The uppermost track is elevated to ensure that the steps can ascend and descend smoothly without obstruction, thus facilitating the safe and efficient operation of the escalator. By positioning the step chain axle at the uppermost track, engineers ensure proper alignment and function, which is essential for the overall performance of the escalator system. This track design is integral in maintaining the correct spacing and motion of the steps as they transition between the horizontal and inclined sections of the escalator.