Czechoslovak State Railways

Czechoslovak State Railways was the state-owned railway company of Czechoslovakia.
The company was founded in 1918 after the end of the First World War and dissolution of Austria-Hungary. It took over the rolling stock and infrastructure of the Imperial Royal Austrian State Railways.
In 1930 Czechoslovakia had of railways: the fifth-largest network in Europe. Of these 81% were state -owned, and the trend was to nationalize the remaining private railways. Most of the infrastructure was concentrated in the industrial regions of the Czech lands. 87% of the railroads were single-track. 135,000 people were employed on the railways: about 1% of the population.
When Nazi Germany dissolved Czechoslovakia in 1939, the Protectorate of Bohemia and Moravia formed the "Bohemian-Moravian Railway" company under the control of Deutsche Reichsbahn. In the Slovak State, the "Slovak Railways" company was formed.
In 1945, ČSD was re-established.
After the dissolution of Czechoslovakia at the end of 1992, the company was divided into the state-owned České dráhy and Železnice Slovenskej republiky. The fixed infrastructure was transferred to the successor countries according to location; the remainder was divided by 2:1 ratio.

Electrification

Electrification of the railways started gradually during the 1920s. In Prague the trains used a direct current system at 1.5 kV.
To power the line from Prague to Chop, a direct current system using 3 kV was built after 1945.
To the north of this line, trains use direct current with voltage 3 kV, to the south they use alternating current with voltage 25 kV at 50 Hz. These two systems continue today.