1 Plot. Railways of the GDR.NDP "IN THE INTERESTS OF THE ROAD". GDR. NDP in the city park, fountains. In a mobile laboratory, continuous monitoring of air purity is carried out. Experiments are being carried out to create a solid crust on the surface of transported bulk cargo. The excavator is loading coal. Coal is wetted with water. The freight train transports coal in covered wagons. Railroad workers cover open wagons with bulk cargo with tarpaulin. NDP.NDP "MAV" 2 plot. Railways of the Hungarian People's Republic. NDP "GUARANTEED BY ENGINE FUNCTIONALITY" Hungary. A passenger train moves on a railroad track. The pipe smokes. Railway workers are working to reduce the amount of harmful emissions into the atmosphere, diagnose the working order of the engine, fuel equipment of the locomotive, determine the chemical composition of exhaust gases, the concentration of soot in them with the help of special devices. Soviet Railways.NDN "WATER WILL REMAIN CLEAN" Freight train moves along the railroad track. Sleeper impregnation plant structures. On the way to the finished product warehouse, some of the antiseptic drips to the ground. Type of treatment facilities to prevent poisoning of soil and water bodies with toxic substances. Workers, laboratory assistants are working on water purification. NDP on the flocator, oil, resin and water are distributed in it. The driver controls the train.