What should the driver of a tram equipped with sandboxes do in the absence of sand in the containers?

Sandboxes are a key safety feature on a tram, as sand increases the friction between the wheels and the rails, which aids braking and prevents skidding. Operating with empty tanks poses a serious hazard, therefore the tram driver is obliged to refill the sand at the earliest possible opportunity. This task is performed in designated locations, such as terminal loops or depots, using special, dry quartz sand.