 In electrified areas, a workaround is needed to allow the traction current, of the order of thousands of amps, to return to the substation.This may be achieved by having no insulated block joints in one of the rails, called the return rail.If both rails are needed to carry the heavy traction return current, then insulated blockjoints are provided in both rails, and impedance bonds are provided to carry the traction current around the insulated joints.