The Soviet DDSG motor tug Rainburg active on the Danube according to a CIA report dated 10 June 1955

An item dealing with the Danube shipping movements reported that on 29 March 1955 was sighted on the position DKM 1725 the first DDSG (Sowjetische Donau Dampf-Schiffahrts GesellschaftmbH) tug ms Rainburg while towing empty tankers downstream.

Source
The report was published on www.archive.org, document number CIA-RDP80-00810A007000090002-6