Testing slabs for pads under railway sleepers

Testing slabs for pads under railway sleepers


Among the pivotal science-research activities of the Institute of Railway Structures and Constructions at the Faculty of Civil Engineering, Brno University of Technology, is designing modern, effective railroad structures in connection with increasing train speeds on railroads. One of the important employee inventions which solves the above-mentioned issue and which originates from this institute is a testing slab for under-sleeper pads.

The inventors are: Doc. Otto Plášek, PhD., who works as the head of the Institute of Railway Structures and Constructions at the Faculty of Civil Engineering, Brno University of Technology, and Ing. Richard Svoboda, PhD., an employee of the same institute, who has also played a major part in ensuring that the under-sleeper pad is protected as a utility model.

The testing slab for testing under-sleeper pads was designed in response to practical requirements and is intended for testing under-sleeper pads used for protecting the track bed against dynamic strain. The under-sleeper bed constitutes a flexible layer which makes up an important part of the rail structure, where it co-functions in reducing the rigidity of the railway. The specific task of the testing slab is to determine the vertical rigidity of under-sleeper pads, which is one of the basic properties verified in under-sleeper pads.

At present, there are two standard procedures for verifying the vertical rigidity of under-sleeper pads. However, both ways of testing under-sleeper pads have their pitfalls, and measurements using these testing methods do not have sufficient predictive value. These reasons were the main driving force which led the inventors to design a new testing slab in order to ensure the repeatability of the test and improve its real-life predictive capacity. For this purpose, the optimal properties of the new testing slab were defined: simplicity, a geometrically defined shape, non-sensitivity to the position and orientation of a sample on the slab, pattern dimensions corresponding to the fraction of the testing body dimensions, the option to realize stress in the form of straining the under-sleeper material, and dimensions the would allow potential testing of the whole sleeper with a flexible loading area at least in the space under this loading area. 

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At present, as part of the TACR project “Sleepers with a flexible loading area”, Doc. Plášek  is cooperating with ŽPSV a.s., a prominent company with a tradition of over 50 years supplying concrete products for the building industry and which focuses on transport (railroad, road) and buildings. Researchers working on this project are cooperating with experts from across Europe to develop the slab as part of the UIC (Union internationale des chemins de fer) project “Under-sleeper pads in railways”. A modified design of the testing slab has already been incorporated in the plan of the European standard, which is now in the official review process. More than twenty pieces of the newly designed slab have been distributed to testing laboratories across Europe, and even before the new standard has been approved, the slab is starting to be considered as the standard for testing under-sleeper pads.

The research in which the registered subject of industrial property was developed was supported under the research project MS12701918 “Progressive Reliable and Durable Supporting Building Structures” (MSM 0021630519).


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