Research purposes ： In order to clarify the influence of longitudinal mechanical behavior between the bridge and the ballastless track on the warpig of reinforced concrete slabs in the subgrade - bridge transition section， a mechanical model including CWR and slab on bridge is set up, so as to study the effects of the restriction of bridges and track structure，the rail additional expansion and contraction force，and the temperature gradient of the slab on the slab warping.
Research conclusions: (1) When considering the restriction effect of bridge and rail，the upwarpig increased by 28% reaching to 2. 5mm compared with no consideration of the bridge and track structure. When considering the rail longitudinal force，the upwarpig of the slab decreased by 44% reaching to 1 4mm，and the stronger rail longitudinal force results in more reduction of the slab warping. (2 ) When considering the positive temperature gradient effect, the
warpig increased by about 43% reaching to 2. 1 mm. The negative temperature gradient effect made the warpig decrease by 14%. ( 3 ) The more increase of the bridge temperature led to the smaller upwarpig， but the impact decreased gradually when the bridge temperature reached high enough. (4) The warpig o the slab greatly increased by  1.2 times reaching to 7. 8 mm when laying the rail expansion joint ( REJ) in the beam gap of large - span bridge compared with lay small resistance fasteners in main bridge. (5 ) The research conclusions have certain guiding significance for the optimization of the design theory and engineering practice in the subgrade - bridge transition section.