When was the spirit of iron ox the concentrated expression of railway workers' spirit?

Iron ox spirit is the concentrated expression of railway workers' spirit in the liberation period. According to the relevant public information, 1949, 1949, on February 5th, in recognition of the outstanding contribution made by No.96 locomotive, Harbin Railway Bureau officially named No.96 locomotive Tieniu, which means an old cow who swaggered, worked hard and worked hard.