The transverse stiffness limitation index ? the permissible ultimate width / span ratio b / l of the continuous steel truss girder of railway bridge is analyzed in accordance with the analytic theories of random vibration of train ? bridge time - variation system and the required derailment coefficients and comfort of drivers and passengers in train running through the bridge . the limitation index in question may be referred to in the design of the continuous steel truss girders of railway bridges 基于列车-桥梁时变系统随机振动分析理论，按照桥上列车脱轨安全系数和司机、旅客舒适度的要求，对铁路连续钢桁梁桥横向刚度限值-桥梁容许极限宽跨比b / l进行了分析，对铁路连续钢桁梁桥的设计具有一定的参考作用。
