Rail Pad With Localized Transverse Webs For Noise And Decoupling
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Solution Overview
Problem
Existing rail pads struggle to achieve effective elastic decoupling between rails and sleepers while minimizing rail noise, with very stiff layers reducing noise but compromising decoupling and very soft layers increasing noise and rail movement.
Innovation Solution
An intermediate layer with longitudinal and transverse webs, where the transverse webs are disproportionately reinforced at the ends to reduce rail vibrations, and the longitudinal webs allow for decoupling between the rail and sleeper, featuring a design with specific indentations and material variations for optimal damping and rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If very stiff intermediate layers are used, then rail noise is reduced, but elastic decoupling between rail and sleeper deteriorates
Solution Approach 1:
The intermediate layer features non-uniform cross-sectional shape with varying thickness: thicker at the ends (with transverse webs extending beyond rail width) and thinner in the middle. This local variation allows the end regions to provide stiffness for noise reduction while the central region maintains elasticity for decoupling, resolving the contradiction between noise control and elastic decoupling.
2Reliability
If very soft intermediate layers are used, then elastic decoupling is improved, but rail noise increases
Solution Approach 1:
The intermediate layer features non-uniform cross-sectional shape with varying thickness: thicker at the ends (with transverse webs extending beyond rail width) and thinner in the middle. This local variation allows the end regions to provide stiffness for noise reduction while the central region maintains elasticity for decoupling, resolving the contradiction between noise control and elastic decoupling.
3Ease of manufacture
If the intermediate layer is uniformly thick, then manufacturing is simplified, but rail vibrations in longitudinal direction are not effectively prevented
Solution Approach 1:
The intermediate layer features non-uniform cross-sectional shape with varying thickness: thicker at the ends (with transverse webs extending beyond rail width) and thinner in the middle. This local variation allows the end regions to provide stiffness for noise reduction while the central region maintains elasticity for decoupling, resolving the contradiction between noise control and elastic decoupling.
Solution Approach 2:
The patent introduces transverse webs that extend in the width direction beyond the rail width, creating a three-dimensional structure with varying thickness. This dimensional approach allows the end regions to provide additional stiffness against longitudinal vibrations while maintaining overall manufacturability through moldable geometry.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces rail noise while maintaining good elastic decoupling, with a static stiffness of ≤350 kN/mm and a dynamic-to-static stiffness ratio ≥1.5, enhancing the intermediate layer's support and damping characteristics.
Implementation Method 1
Elastic rail pads have the task of elastically decoupling the rail from the underlying (railway) sleeper. The forces absorbed by the rail are dissipated via the intermediate rail layer into the sleeper
Implementation Method 2
The intermediate layer is preferably made of an elastomeric or rubber-elastic material... the at least one longitudinal web being formed or defined or limited by longitudinal depressions... the at least one transverse web is formed or defined or delimited by one or more transverse depressions
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to an intermediate layer (10) for arranging between a rail cross-tie and a track, which intermediate layer has a longitudinal web (20) on the top side (11) thereof and/or on the bottom side (12) thereof, which longitudinal web extends in a longitudinal direction (L), wherein the longitudinal web (20) ends in or at at least one transverse web (40), the length of which transversely to the longitudinal direction (L) is greater than a width of the longitudinal web (20) in this direction, wherein the at least one longitudinal web (20) is formed by longitudinal recesses (62), and wherein the at least one transverse web (40) is formed by one or more transverse recesses (60).