Magnetic drain plug in rail transit gearbox and machining method of magnetic drain plug

The invention relates to a magnetic drain plug in a rail transit gearbox and a machining method of the magnetic drain plug. The magnetic drain plug comprises a drain plug body and a permanent magnet; the drain plug body comprises an outer thread plug cock of a cylindrical sinking hole, a permanent magnet fixing area, a riveting area and a containing area are arranged in the outer thread plug cock of the cylindrical sinking hole, and the permanent magnet is fixed to the permanent magnet fixing area on the bottom of the sinking hole through the riveting area. According to the magnetic drain plug, the permanent magnet is fixed into the sinking hole of the magnetic drain plug through the riveting side, fixing is reliable, the structure is compact, maintaining is avoided, the containing area is arranged on the drain plug body, absorbed magnetic impurities can be stored, and are prevented from repeatedly entering lubricating oil and affecting the lubricating oil property, a plurality of sets of anti-loosening iron