Monitoring Track Transition Zones in Railways

This manuscript presents the first measurement program and data collection on the Dinatrans track transition solution after it was installed in a track section in the north of Spain (Galicia). The Dinatrans solution was created to address the limitations of several track transition solutions. This novel solution consists of two inner and outer rails from slab track to ballast track, pads with different stiffness over sleepers of variable lengths installed from ballast track to slab track, and a simple substructure formed by non-structural concrete poured over the natural ground. The main objective of this research was to assess the suitability and the initial performance of the Dinatrans track transition solution. The measured variables for these initial real-world tests were vertical accelerations on sleepers, shear stress on rails, vertical displacements on rails and vertical displacements on sleepers. All measurements of these variables were obtained in an in-situ program by installing vertical accelerometers and LVDTs on the track structure and extensometer gauges on the rails and sleepers. The methodology and the procedures followed are described. The Dinatrans initial solution was compared with the Standard solution used in Spain using these initial measurements. This field analysis provides an initial understanding of the performance of the new track transition. Further measurements will be required to check the track transition performance over the long term; however, no maintenance works have been necessary since construction (2016).

Vibration-reduction optimization of the point-supporting floating-slab track based on local resonance mechanism

With the continuous increase of subway operating mileage, the problem of subway vibration has become more and more significant. Nowadays, the point-supported floating-slab track is recognized as the best method to control track vibration, which is mainly designed based on the mass-spring-damping theory. How to further improve the vibration control ability of the point-supported floating-slab track? In this paper, a new type of rubber point-supported floating slab track is designed based on the local resonance theory. Through calculation and dynamic test, it is obtained as follows: (1) The band gap of the point support structure by local resonance type depends on the two vertical vibration modes. (2) As the elastic modulus of the cladding layer increases, the bandwidth of the band gap of the corresponding structure increases significantly. (3) The increase of the vibrator density can increase the bandwidth, while reducing the start and stop frequencies, which is beneficial to attenuate the resonance of the floating-slab track. (4) The cushion material parameters of point support structure by local resonance type 2 will not affect the band gap. The increase in sleeve density will reduce the band gap, which is not conducive to vibration reduction. Local resonance type floating-slab track will be the development direction of track vibration-reduction measures in the future.

Design theories and maintenance technologies of slab tracks for high-speed railways in China: a review

The durability and reliability of slab track structures are essential for the long-term safety and stable operation of high-speed railways. In order to provide a solid theoretical basis and technical reference for the advancement of high-speed railway quality, this paper comprehensively discusses design theories of slab track structures, service performance evolution and maintenance technologies, and reviews the innovation happening in the industry. On top of that, the damage evolution, fatigue features and durability of slab tracks, which are highly relevant to serviceability, are summarized, and the future research trend of slab track service behaviours is pointed out. In addition, this paper summarizes the rules of establishing standards for damage maintenance, typical solutions for repairing damage and methods of evaluating the maintenance outcomes that combine field tests and numerical simulations. It also envisions a future direction where advanced testing technologies would assist the evaluation of maintenance effects.