 Once the fill-dump process and passenger boarding were complete the brakes were gradually released and since both cars were attached by a single cable passing over a pulley arrangement at Glion, the heavier car descended the slope carrying up the lighter car.The process was then repeated so the car uphill was always filled and the one downhill always empty and thus pulled uphill when brakes were released.An added picturesque note was that the two car operators were communicating for synchronisation with whistles instead of an intercom or similar device.