The 15 kV a.c., 16 2/3 Hz, overhead system is used widely in Germany, Denmark and Austria. It is not used in the UK.
In Germany the 16 2/3 Hz electricity supply comes from railway generating stations. Power is transmitted at 110 kV via overhead lines. The power is transformed from 110 kV to 15 kV at railway substations that feed the railway overhead system.
Re: Why is this setup used?#128707 10/19/0309:46 AM10/19/0309:46 AM
that was a quick answer. It is indeed the transmission for the train lines. Andy and Paul are right about the reason - the frequency is different from that of the ordinary power grid.
I think your source is wrong. Denmark uses 50Hz, 25kV for the trains whereas Sweden and Norway use 16 2/3Hz, 15kV. This has forced trains that run between the countries to be dual voltage / dual frequency.
[This message has been edited by C-H (edited 10-19-2003).]