Railway Derailment Risk Detection Using Multi-Directional Rail Strain Gauges

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Solution Overview

Problem

Existing methods for detecting rail vehicle derailment risks are limited in their ability to accurately record and evaluate all deformations on the rail, leading to unreliable detection of derailment factors due to the special arrangement of measuring elements and their limited number of positions.

Innovation Solution

The solution involves strain gauges attached to the outer edge of the rail head and foot, with bar-shaped force introduction and dissipation parts connected to the rail foot and sleeper, featuring measuring indentations for horizontal and vertical force detection, and an electronic signal evaluation device forming a continuous information array to assess instability tendencies and track displacement forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If measuring elements are arranged on the underside of the rail head and on the upper side of the rails, then elastic deformations can be detected, but the reliability of derailment factor detection is limited due to inability to detect all deformations

Engineering Contradiction:
Improvereliability of derailment factor detectionVSAvoidcompleteness of deformation detection
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The rail is divided into multiple measurement zones with different types of measuring elements: strain gauges on the rail head for vertical forces, strain gauges on the rail web for longitudinal and transverse forces, and strain gauges on the rail foot for horizontal displacements. This segmentation allows comprehensive detection of all deformation types occurring on the rail.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extends measurement from traditional vertical-only strain gauges to multiple dimensions by adding strain gauges that detect longitudinal, transverse, and horizontal deformations. The bar-shaped force introduction and dissipation parts with measuring indentations add a horizontal displacement measurement dimension, enabling three-dimensional deformation detection.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If a limited number of measuring elements are used on the rail, then device complexity is reduced, but the ability to record all deformations and detect derailment factors reliably is insufficient

Engineering Contradiction:
Improvedetection of derailment factorsVSAvoidnumber and arrangement of measuring elements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bar-shaped force introduction part serves multiple functions: it introduces forces to the rail foot, provides a structure for measuring indentations to detect horizontal displacements, and enables detection of both vertical and horizontal components of wheel-rail forces. This multi-functionality reduces the need for separate measurement devices.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The deformation body with measuring indentations acts as an intermediary between the bar-shaped force introduction part and the rail foot. It transforms complex multi-axial forces into measurable deformation patterns that can be detected by strain gauges, simplifying the overall measurement system while maintaining comprehensive detection capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If strain gauges are attached at multiple angles to the neutral axis on the rail web, then longitudinal and transverse forces can be recorded, but the arrangement complexity increases

Engineering Contradiction:
Improvedetection of longitudinal and transverse forcesVSAvoidarrangement of strain gauges
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention uses asymmetric placement of strain gauges at specific angles (0°, +45°, -45°) to the neutral axis on the rail web, rather than symmetric placement. This asymmetric arrangement optimizes the detection of longitudinal and transverse forces by aligning measurement axes with the principal stress directions, reducing the number of gauges needed while maintaining measurement precision.

Inventive Principle:
Principle #4Asymmetry

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

This approach enables reliable and precise detection of derailment risk factors by breaking down rail movements into relevant components near the wheel contact point, providing objective and timely safety assessments with redundant measurement systems and high-frequency simulation support.

Implementation Method 1

measuring elements on the outer edge of the rail head and on both outer edges of the rail foot are designed as strain gauges which record horizontal displacements

Methodology Applied
Scientific EffectStrain gauge measurement: Deformation

Implementation Method 2

strain gauges are attached to the rail web in the neutral line at a 0 degree angle to the neutral line to record longitudinal stresses

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

at least one pair of measuring indentations is provided on at least one deformation body between the force introduction and force output parts

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP1904356B1Method and device for determining the risk of derailment of railway vehicles
Publication Date: 2012.11.21 HOTTINGER BRUEEL & KJAER GMBH
  • EP1904356B1 patent drawingFigure 1a
  • EP1904356B1 patent drawingFigure 1b
  • EP1904356B1 patent drawingFigure 2

AI summary

The invention relates to a method for determining the risk of derailment of railway vehicles, using a measuring section that consists of a row of measuring elements which are attached to the rails (S) and sense force effects and send corresponding electrical signals to an electronic signal evaluation device, signals being derived from measuring elements that are attached to the outer edge of the rail head (SKR) and to both edges of the rail flange (SFR), said signals indicating the movement of the rails in the horizontal direction, measuring elements on both sides of the web (STL) of the rail sensing the longitudinal stress on the rail and a measuring element (SFM) which supports the rail flange sensing horizontal and vertical forces which are applied to the rail and travel in a horizontal direction according to the point of contact of the wheel, a continuous array of information then being generated in the evaluation device from the transmitted signals which shows the instabilities and rail displacement forces.