Abstract: A switching circuit for implementing coupling at a random end of a train includes a coupling change-over switch which includes a switching position, a normal position, and a disconnected position. The coupling change-over switch includes a group of terminals A, B, C, D, E, F, G, and H that are related to a train running direction signal. The terminals A and C are connected to each other, as well as the terminals E and G, the terminals B and H and the terminals D and F. The pair terminals A and C and the pair of terminals E and G act as terminals of forward and backward running signal train control lines respectively. The pair of terminals B and H and the pair of terminals D and F are connected to terminals of forward and backward running signal wires of a train electric coupler connector respectively.