In what situation is it recommended to use sandboxes fitted on a tram?

Sanders are devices on a tram which dispense sand onto the rails just in front of the vehicle's wheels. Their primary function is to increase the friction and adhesion of the wheels to the track. In the event of sudden emergency braking, especially on a slippery surface, the use of sand is crucial as it significantly shortens the braking distance and helps to prevent the wheels from locking.