The invention discloses a city
rail traffic traction system. The city
rail traffic traction system comprises a
control unit, an energy storing unit, a traction current converting unit and a
traction motor, wherein the traction current converting unit is connected between two
direct current buses of an external
power supply unit; the energy storing unit is connected with the
direct current buses of the external
power supply unit and the traction current converting unit; the energy storing unit is used for storing
electric energy provided by the external
power supply unit; the traction current converting unit is connected with the
control unit and the
traction motor; the
control unit is used for controlling the traction current converting unit to perform charging and energy storing and / or discharging and energy releasing on the energy storing unit, so that
direct current electric energy stored in the energy storing unit is converted to
alternate current electric energy which is outputted to the
traction motor to drive a
train to operate. According to the city
rail traffic traction system provided by the invention, when the
train approaches a
station and parks, the energy storing unit is charged; during the running of the
train, electric energy stored in the energy storing unit is used for the train, and an uninterrupted
contact line is not needed to be adopted for supplying
electricity to the train, so that the project cost is reduced, and potential safety hazards caused by the uninterrupted
contact line are also reduced.