Source:[2][3][4] The line was constructed and operated under the original name Elektryczne Koleje Dojazdowe (Electric Commuter Rail) by a privately owned electrical power industry consortium Siła i Światło (Power and Light) established with the participation of British capital shortly after Poland regained independence after World War I in 1918.

The consortium sought to build an electric railway in order to accelerate economic development and increase the demand for its services.

To achieve this goal it created in 1922 the company Elektryczne Koleje Dojazdowe S.A., owned in 40% by Siła i Światło, 25% by one of the financing banks and the remaining 35% held by small shareholders.

In 1927 a 32.4 kilometres long standard gauge line electrified at 650 V DC with overhead wire was opened, linking Grodzisk Mazowiecki with the center of Warsaw.

Its core business had not yet reached profitability, however the company made money reselling real estate which gained in value significantly due to the railroad.

In 1972 the almost half-a-century-old English Electric railcars were replaced by new PKP class EN94 EMUs produced by Pafawag in Wrocław designed especially for the line.

In 2001 with the restructuring of the Polish State Railways a separate company called PKP Warszawska Kolej Dojazdowa Sp.

In 2004 Warszawska Kolej Dojazdowa received a single prototype of a new EMU designated PKP class EN95 built by PESA in Bydgoszcz which remains in service today, however no further units of this type have been ordered.

In 2020 Warszawska Kolej Dojazdowa started preparations to double-track the 7.5-km long Podkowa Leśna Główna – Grodzisk Mazowiecki Radońska section.