Analysis of the performance of under-sleeper pads in highspeed line transition zones

[EN] In many high-speed railway lines, the zones between embankments and structures may present some discontinuities, in terms of track geometry and track stiffness, which may create discomfort for passengers, induce deterioration of track and vehicle materials and even raise the risk of derailment to dangerous levels. In the attempt to attenuate the consequences of such problems, some solutions pointing at progressively changing the vertical stiffness in the railway track have been tested, such as transition zones or pads placed either between the rails and the sleepers or under the sleepers. The contribution of under-sleeper pads in transition regions and their effect on the railway infrastructure is specifically analysed in the present paper. The results obtained are of interest since they provide useful information for railway managers on infrastructure design and justify the need to implement such transition ones.Insa Franco, R.; Salvador Zuriaga, P.; Inarejos Mesa, J.; Medina González, L. (2014). Analysis of the performance of under-sleeper pads in highspeed line transition zones. Proceedings of the Institution of Civil Engineers - Transport. 167(2):63-77. doi:10.1680/tran.11.00033S6377167

Impermeable membranes for slab-track settlement mitigation

A series of numerical simulations is used to explore the effect of the geometrical disposition of impermeable membranes in the overall performance of slab-track railway earthworks, with particular reference to the generation of settlement during several years of exposure to the atmosphere and the admissibility of these post-construction deformations according to the available standards. A methodology suitable to account for the effects of rail traffic loading and environmental actions over its service life is presented. To emphasise the effect of the water-impermeable membranes on the atmospheric-induced embankment irreversible deformations, both semi-arid and wet climate conditions were investigated, making use of real climate data for a period of 10 years. The numerical results show that the calculated settlement can be beyond the admissible values and that the use of impermeable membranes is an available alternative for its mitigation.Peer ReviewedPostprint (author's final draft