The innovative Pipe Technologies division of the leading Danish civil engineering contractor Per Aarsleff A/S has successfully completed, on schedule and to budget, one of its most challenging pipe line restoration projects under extreme weather conditions in the centre of the Russian capital Moscow. Working in temperatures down to -20°C, Aarsleff Pipe Technologies cleaned and inspected the inside of a 300 m long section of a low pressure, wastewater inverted siphon under the River Moscow, prior to installing a new thin walled resin impregnated felt lining in the flooded 1.4 m diameter pipe, using its novel cured in place pipe (CIPP) restoration technique, without any disruption to road or river traffic. The special lining, resembling a flattened flexible tube, was tailor made from layers of felt and impregnated with a special resin. The outer layer was coated with a polypropylene skin. This was done because, during the novel installation process on site, the liner was turned inside out as it was inverted and pushed by water pressure into the existing flooded rigid siphon. The wall of the existing Savinskiy steel siphon, built in 1956, acted as shuttering and the polypropylene coating became the inside surface of the new lining. After installation water inside the siphon was heated to about 85°C to cure the resin, transforming the inverted flexible tube into a rigid, thin walled smooth bore lining, capable of lasting over 100 years.