This article aims to investigate the vibrational energy properties of the twin-block ballastless track with anti-vibration structure (TBTAS) by mobility power flow method. Power flow of the components in TBTAS and bridge are deduced and power flow transfer rate is proposed to present the vibrational energy transmission property of the TBTAS-bridge system. Power flow of rail, twin-block slab and bridge in frequency domain is calculated based on a train-trackbridge interaction model. The effect of the stiffness of the elastic pad on power flow is discussed. The results show that the power flow of the rail exhibits a broad peak in the frequency range of 100–400 Hz which corresponds to the broad peak of the rail mobility and exhibits another peak around 1,000 Hz which is the pinned-pinned vibration frequency of the rail. By using elastic pad, the power flow of the bridge reduces by a maximum of 43 dB in the frequency range of 1–1,000 Hz. The power flow transfer rate shows that the vibrational energy concentrates in the slab. The vibrational energy of slab and bridge reaches the balance when the stiffness of the elastic pad is 40 MPa/m.

In order to investigate the vibration characteristics of a composite sleeper-ballasted track and provide a basis for further popularization, a vehicle–track dynamic coupling model is established and the viscoelastic properties of the composite sleeper are considered. The power flow method is employed to reveal the power flow distribution characteristics of the composite sleeper. The results show that the viscoelastic properties of the composite sleeper have little influence on the rail power and have a greater influence on the power flow of the sleeper and ballast bed in some frequency ranges. The viscoelastic properties of the composite sleeper can effectively improve the calculation accuracy of the track structure’s power flow. Compared with the type-III pre-stressed concrete sleepers widely used in China, composite sleepers consume more energy in the vibration process due to their own physical characteristics, which reduces the power flow transmitted downward and relieves vibration on the ballast bed, especially in the ranges of 80–125 Hz and 250–400 Hz. The temperature change mainly affects the power flow of the composite sleeper in the frequency range above 50 Hz. As the temperature increases, the modulus of the composite sleeper decreases and the vibration reduction effect of the ballast bed is improved.

As a symmetrical structure in track system, the dynamic properties of recycled composite sleepers are important factors affecting the vibration characteristics of track structure. To study the viscoelastic dynamic properties of the composite sleeper, dynamic mechanical analysis (DMA) tests of a composite sleeper at −5 to 30 °C and 1–60 Hz were first carried out, and then the time-temperature superposition (TTS) and the Williams–Landel–Ferry (WLF) formula were used to predict the dynamic properties of a composite sleeper at a wider frequency range. Finally, the generalized Maxwell model was adopted to characterize the dynamic properties of the composite sleeper, which provides parameters and theoretical models for dynamic analysis. The research results show that the composite sleeper has obvious viscoelasticity. Its modulus is large at low temperature or high frequency. On the contrary, the modulus is small at high temperature or low frequency. Under the test conditions, its complex modulus ranges from 1500 to 2700 MPa. The loss factor is in the range of 0.08–0.13. Using the generalized Maxwell model (n = 4), which can better reflect the dynamic properties of the composite sleeper.