HVDC Ekibasus-Tambov was a never finished powerline from Ekibastus in Kazhakstan to Tambov in Russia, from which only the towers of the Volga Crossing exist at 51°50′59″N 47°01′09″E. However some traces of this line may still exist, so you can find at the powerline trace http://www.openstreetmap.org/browse/way/148897670 some basements of dismantled pylons, which I believe were once used for the towers of HVDC Ekibastus-Tambov.
It would be great, if one could find out the exact route, on which this powerline should have run and map it