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Subway tunnel construction often crosses existing railways, and the soil loss caused by shield construction will inevitably lead to deformation of the surrounding strata and uneven settlement of the adjacent railway tracks, but there are few studies on the existing railway deformation caused by double shield construction in soil–rock composite strata. In this paper, based on the field monitoring data, the deformation analysis of the railway under-crossed by double shield tunnel in soil–rock​ composite stratum was carried out, and the influence law of hard-layer ratio, tunnel burial depth and railway roadbed reinforcement on the railway track deformation was revealed by numerical simulation. Results show that the track settlement mainly occurred in the middle and late stages of the shield crossing the railway. The track settlement showed an obvious trend of decreasing with the increase of hard-layer ratio or tunnel buried depth. The roadbed reinforcement can significantly reduce the settlement of the railway track, the smaller the hard-layer ratio, the better the roadbed reinforcement effect.