Rybinka is one more underground river of Moscow. It begins as a drainage system of the railway, then it comes into a ditch two meters wide (6.56 ft) and later into an arched section with height of about 1,6 meters (5.2 ft).
Here diggers need to have some chemical protection. The arch is about 300 meters long (984 ft).
Soon we come into the tube.
The bottom is rather slippery.