Yes it does, thanks a lot!
Apparently Denmark is an island between Germany and Sweden using 25 kV/50 Hz, the modern European railway standard.
The early adopters of electrical railways chose either DC or low-frequency AC because such motors can be controlled simply with series resistors. Before the days of solid state inverters controlling the speed of a 50 Hz AC motor was incredibly complex and required chunky machinery on each loco/EMU. The Hungarians went through all that trouble when they electrified their railways in the 1930s because it was still cheaper than dedicated railway power plants or huge rotary converter stations as we still have in Austria (Germany and Switzerland are moving over to solid state inverters). Seems like Denmark chose the Hungarian way.
Edit: low-frequency AC had one huge advantage, it could be transformed on board of the train. Motors at that time couldn't run on more than about 1000-1500 V so DC systems could only go up to 3 kV with series-wired motors but AC systems could easily have 15 kV overhead wire voltage and transform it down to something manageable. The high voltage greatly reduces current and voltage drop, that's why some countries have a mix of power systems, DC on older lines and AC on newer high-speed lines. Apparently the Dutch can't run electric freight trains because of the limits of their 1.5 kV DC overhead supply!
The Czech Republic is split, the North is DC and the South is 50 Hz AC.
