Cleaning with the BR 47 35 esc is performed with the escalator or travelator running. The machine is positioned at the bottom of the escalator. Special nozzles spray the cleaning solution onto the scrubbing brushes, which then apply it to the treads. (Treads must move away from the machine.) Dirty cleaning solution is vacuumed away gain in the same operation. This is assisted by pick-up brushes which convey the solution to the suction nozzles. The shape of the brush head and the central brush motor allow the brushes to reach and clean the outermost grooves in the tread. A centring skid in the middle of the brush head keeps the machine in alignment during the cleaning process. The BR 47 35 esc is suitable for many different makes of escalators and travelators. Four different sets of combs are available to suit most makes. They engage in the tread grooves to provide a seal between the machine and the treads for efficient pickup.