The invention provides an electric source system of a track traffic locomotive. The electric source system comprises a direct current busbar for directly providing electricity for the locomotive, and a locomotive direct current load connected with the direct current busbar, wherein a bidirectional electric source release and absorption device is arranged between the direct current busbar and the locomotive direct current load. When the track traffic locomotive is started and braked, the electric source system has the effect of smoothing the voltages of an electrical network, and the influence of the track traffic locomotive on the electrical network is reduced; when the track traffic locomotive is braked, energy generated in the braking process of the track traffic locomotive can be recovered, so that the utilization efficiency of energy resources is improved, and the purposes of energy conservation and environmental protection are achieved; when the track traffic locomotive has electricity supply failure due to the locomotive or the electrical network, emergency towing can be started, so that the locomotive is towed to a safe position, the situation that the locomotive occupies lines is avoided, the operation efficiency is improved, and urgent failure handling capacity is improved. The scheme adopted by the electric source system is upgraded based on an original standby electric source, so that space usage is small, and the technology cost is reduced; according to the residual capacity of current batteries, an emergency towing scheme can be automatically made, and the control is more intelligentized.