The design, application and quick changing technology of dies were mainly introduced for an automatic forging production line with a hot die forging press of 63 MN as the main forging equipment. The medium forgings in railway rolling stock were manufactured by hot die forging press of 63 MN, mechanical trimming press of 8 MN and hydraulic sizing press of 10 MN in production line. According to the characteristics of different forgings produced by production line, different die layouts were designed and the ejecting positions of the die set and press were determined. The die life could be prolonged by the die manufacturing method of taking the 5CrMnMo as the die substrate, welding forged cavity and edge of cutting die by H13 electrode. The die changing time could be reduced and an efficient operation of the production line could be ensured by employing the quick changing technology.