The invention provides a traction system of a railway car having a traction converter capable of continuing independent running operation when one of the power conversion means fails, thereby minimizing the disturbance of train operation diagram. A traction system of a railway receiving input of AC power generated via an AC generator 2 via a selector 9 to a first power conversion means 3, converting the DC power via a second power conversion means 4 to AC power, and driving an AC traction motor 5 via the selector 9, wherein a storage system 8 is connected to a DC link between the first power conversion means 3 and the second power conversion means 4, and when either one of the power conversion means fails, connects the AC generator 2 to the healthy-operating power conversion means being operated to perform AC/DC conversion to charge the storage system 8, and when the storage system 8 is at a sufficiently charged state, operates the healthy-operating power conversion means to perform DC/AC conversion so as to drive the AC traction motor 5 via the stored energy of the storage system to thereby accelerate the railway car.