Traction current lines are always equipped with an earth conductor. In some cases, two earth conductors are used: for example in, Germany, in cases where the traction current line is carried on pylons together with three phase AC, like the line to the nuclear power station at Neckarwestheim. Similarly, in Austria there are some traction current lines equipped with two earth ropes. Alternatives to traction current lines In Sweden, Norway and some areas of the former GDR three phase AC from the public grid is converted into single phase AC with a frequency of 16.7 Hz in substations close to the railways. In these regions there are no traction current lines. Also in countries in which the electric trains run with direct current or with single phase AC with the frequency of the general power grid, the required conversion of the current is performed in the substations, so that in these countries no traction current lines are needed. See also Third rail Traction current converter plant Traction powerstation Electric power distribution Electric rail transport