Abstract: At present, oil loading and unloading in railway tank wagon is mainly from top, this way is prone to airlock?and static electricity with low unloading efficiency and high loss. The technology of bottom loading and unloading?for automobile tanker which is already mature, especially the advent of new residue-free valve, offers new thinking to?the renovation of railway light oil tank wagon. Based on the working principle of the new residue-free valve, the paper?demonstrates the feasibility to bottom loading and unloading railway tanker. At the same time, the mature safety measures?and administrative regulations of bottom unloading can provide a support to the smooth implementation of bottom loading and unloading railway tanker. The application of this technology can solve the problems in air-lock and static electricity, reduce loss, save cost, resulting in some economic and social benefits.