Research on Refined Design of Single Cross-over in Urban Rail Transit
[Objective]The key to high quality development of urban rail transit lies in cost reduction,efficiency improve-ment,and sustainability,requiring the refined design and the reduction of design redundancy.Crossovers are one of the most common sidings in the design of metro stations,and research on the refined design of single crossover length can reduce the civil engineering quantity in the turnout area and save invest-ment.[Method]Aiming at minimizing the length of single crossover,a calculation model for the distance between track centers,the length of the single crossover,the circular curve radius inserted with the reverse curve and deflection angle is es-tablished to study the refined design of the single crossover length.[Result & Conclusion]The research results show that:Using No.9 turnout for calculation and considering the significance level of a 5%reduction in the turnout area length,when the track centerline distance for Type A vehicle is≥10.207 m(or when the track centerline distance for Type B vehicle is ≥9.440 m),it is recommended to adopt the single crossover with an inserted reverse curve.When the track cen-terline distance is ≥12.3 m for Type A vehicle(or when the track centerline distance is ≥ 10.9 m for Type B vehicle),the circular curve radius R of the reverse curve takes the lower lim-it value of 200 m,which can make the total length of the single crossover the shortest.When the track centerline distance is<12.3 m for Type A vehicle(or when the track centerline dis-tance is<10.9 m for Type B vehicle),R needs to be appro-priately increased in order to meet the minimum length require-ment for circular curve of the reverse curve.The optimal com-bination of R and the deflection angle φ of the circular curve can be obtained by back-calculating from the calculation model.