The union was founded on 2 February 1987, with the merger of the
National Railway Locomotive Engineers' Union (Doro) and the
Japan Railway Workers' Union (Tetsuro). The merger was in response to the privatisation of
Japanese National Railways, of which both unions were broadly supportive. It affiliated to the
Japanese Trade Union Confederation. In 1992, many former Tetsuro members split away, in protest at the union considering the possibility of strikes, and formed the rival
Japan Railway Trade Unions Confederation. In 1996, the union had 70,710 members, but by 2020, this had fallen to only 22,561. In 2010, a complaint was lodged in the Diet that JR-Soren was being financially controlled by the
Japan Revolutionary Communist League (Revolutionary Marxist Faction). JR-Soren denied the charges. The charge was repeated by
Kansei Nakano and confirmed by several weekly magazines. ==Composition==