Dust cleaning in the Moscow Metro

Dust cleaning in the Moscow Metro
This is one of the methods how they clean the Moscow Metro. A pile of moist wood chippings is a perfect dust absorber. Besides, moist wood chippings won't raise into the air even with the wave from the coming train.
The man is pushing them forward along the platform with a special brush with a lower part protruding to both sides.
There are also electric machines with a revolving brush and a driver driving the machine.
But this old method is still in use, though we cannot see it often.