研究结论：为确保40t 轴重重载铁路安全，应采用大断面高强度钢轨。在梁轨快速相对位移不大于4 mm的控制条件下，40t 轴重重载铁路桥梁合理跨度不宜超过40 m，其桥墩纵向线刚度最小限值大于《高速铁路设计规范》取值，桥墩刚度宜根据计算控制合理的纵向线刚度，钢轨和桥墩共同分配承担制动力。

Research conclusions:To ensure the safety of the heavy － haul railway bearing 40 t axle load of vehicle，the large cross－section rail with high strength． should be used． When the rapid relative displacement of the beam and rail is not more than 4 mm，the span of the bridge for the heavy － haul railway bearing 40 t axle load of vehicle should not exceed 40 m，and at this time，the minimum limit value of the vertical line stiffness of the pier is more than the value in the " Design Specifications for High － speed Railway" ． Therefore，the vertical line stiffness should be controlled by the pier stiffness according to the calculation to make the braking force born by the rail and bridge pier．stiffness should