A simulation model of (117.9+240.0+117.9) m extradosed cable-stayed bridge and ballastless track system with prestressed concrete for high-speed railway was established in consideration of rails, fasteners, track plates, base plates, sliding layers, mortar layers, bridges, friction plates, and end spurs. With the railway bridge and culvert specification TB 10002—2017, highway specification JTG 3362—2018, and European specification Eurocode 2 as reference standards, the mechanical characteristics in seamless lines on long-span extradosed cable-stayed bridges for the high-speed railway under shrinkage and creep effects of ballastless tracks were investigated firstly, and the influence of design parameters such as storage time of girders and relative humidity of concrete was analyzed. The results show that with the prolongation of service time, the stress of track structures increases gradually. When the shrinkage and creep effects of the bridge alone are considered, the maximum tensile stress of the rail is 4.9 MPa, which appears at the end of the girder at the right side, and the maximum compressive stress is 5.2 MPa, which appears near the consolidation mechanism.
When the shrinkage and creep effects of the ballastless track alone are considered, the maximum tensile stress of the rail is 0.9 MPa, and the maximum compressive stress is 1.1 MPa, both of which appear at the end of the girder at the right side. When the shrinkage and creep effects of the bridge and the track are considered at the same time, the maximum tensile stress of the rail is 7.7 MPa, appearing at the end of the girder at the right side, and the maximum compressive stress is 6.5 MPa, appearing near the consolidation mechanism. Prolonging the storage time of the girder and strengthening the concrete maintenance can reduce the influence of shrinkage and creep effects on the rail structure. The research results can provide an important reference for the design of long-span bridges and ballastless tracks.