Tonka (fuel) necessary for the mixture to work as desired, rather than fail catastrophically, is a function both of the ingredients' purity, and of their temperature during use. Tonka (fuel) Tonka (also TONKA-250 and R-Stoff) is the name given to a German-designed rocket propellant first used in the Wasserfall missile; it has also more recently been used by North Korea but found its greatest applications (under the name TG-02) in the Soviet Union, for example, in the propulsion projects of the A.M. Isayev Chemical Engineering Design Bureau. Its name is a reference to the tonka bean; as it was invented during the
Renfe Feve by FEVE before it disappeared were located along or near Spain's Atlantic Ocean and Bay of Biscay coastline, which stretches from Galicia in the northwest, through Asturias and Cantabria to the Basque Country (with a branch extending into Castile and León). Together they formed a large and strategically important system, which was why – unlike the other, more isolated regional railways – they have been retained under the integrated management of FEVE. FEVE operated of track, of which were electrified. An exclusive tourist service operated by FEVE is a long line, the "Transcantábrico", which runs along the entire length of