The invention relates to an assembly for loading and unloading a semi-trailer on a railway wagon, comprising a loading and unloading structure intended to receive the semi-trailer. The loading and unloading structure comprises a lower portion in the form of a support plate intended to carry the semi-trailer and an upper portion in the form of a handling frame intended to be handled and moved by a standard means for handling containers. To this end, the upper portion of the handling frame has a standard container interface intended to be handled and moved by a standard means for handling containers. The support plate and the handling frame are connected either by a fixed link or by a detachable link.