Considering local sleepers supported invalidly, the dynamic analysis is presented for ballastless railway track system subjected to moving loads. The track is modeled as an infinitely Euler-Bernoulli beam with Kelvin viscoelastic foundation. The restrain conditions of system change suddenly at unsupported sleepers. Numerical simulating was carried out by the finite element discrete and Newmarks-method. Dynamic responses of system were analyzed in the case of single or multi-sleeper to be not working properly. Results show that the maximum value of displacement of track is going up 50% approximately due to an invalid sleeper occurring. The amplitude of vibration is two times increase when three sleepers to be hung up. Hence, there would be a bad effect on the vibration control of ballastless railway track system as some sleepers lose efficacy continuously.