Rail Flaw Detection Using Passive Magnetometry and X-Ray Imaging

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Solution Overview

Problem

Current rail inspection technologies are limited by their inability to frequently detect internal rail flaws, require environmentally harmful couplants, necessitate human intervention, and fail to inspect the entire rail, especially in freezing conditions and at the base of the rail.

Innovation Solution

A non-contact method combining passive magnetometry with x-radiation for frequent, remote, and automated rail inspections, using a passive magnetometer to detect magnetic field changes and an x-ray system for detailed imaging, eliminating the need for couplants and human operators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If contact-based ultrasonic inspection is used, then internal rail flaws can be detected, but inspection speed is limited to approximately 20 MPH and freezing temperatures cause couplant to freeze creating air gaps

Engineering Contradiction:

Improveinternal rail flaw detection accuracyVSAvoidinspection speed

Core Design Contradiction:

Measurement precisionVSSpeed

Solution Approach 1:

The patent replaces contact-based mechanical ultrasonic transducers with non-contact electromagnetic induction sensors. The electromagnetic sensors detect flaws through induction without requiring physical contact or couplant, thereby eliminating the speed limitation of 20 MPH and the freezing temperature constraint that causes couplant to freeze and create air gaps.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If contact-based ultrasonic inspection with couplant is used, then signal loss is minimized, but in freezing conditions the couplant freezes creating air gaps and impacting signal performance

Engineering Contradiction:

Improvesignal qualityVSAvoidoperational capability in freezing conditions

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent substitutes electromagnetic induction sensors for contact-based ultrasonic transducers that require couplant. The electromagnetic sensors operate without physical contact, eliminating the reliability issue of couplant freezing and maintaining signal quality across all temperature conditions including freezing environments.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If both automated and manual inspection technologies are combined, then detection probability of internal rail flaws increases, but inspection time increases due to need to stop and manually verify flaws

Engineering Contradiction:

Improveflaw detection accuracyVSAvoidinspection time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent employs multiple electromagnetic induction sensors that automatically detect and verify flaws without requiring manual intervention. The system self-verifies flaws through redundant sensor detection, eliminating the need to stop for manual verification and thereby reducing inspection time while maintaining high detection accuracy.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent enables continuous inspection at high speeds using non-contact electromagnetic sensors that do not require stopping for manual verification. The automated detection and verification process maintains continuous operation, eliminating time loss associated with manual flaw verification while preserving detection accuracy.

Inventive Principle:

Principle #20Continuity of useful action

4Measurement precision

If ultrasonic transducers are used with couplant, then internal rail flaws can be detected, but environmentally harmful anti-freeze solutions must be used in freezing conditions

Engineering Contradiction:

Improveflaw detection capabilityVSAvoidenvironmental harm from anti-freeze couplant

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces contact-based ultrasonic transducers requiring couplant with non-contact electromagnetic induction sensors. This substitution eliminates the need for environmentally harmful anti-freeze couplants while maintaining flaw detection capability across all temperature conditions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 faster, more frequent, and accurate rail inspections, reducing environmental impact and inspection time, while providing comprehensive coverage of the rail, including its base, and allowing for real-time monitoring of flaw growth.

Implementation Method 1

A passive magnetometer senses changes in the magnetic field

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 2

an x-ray system is used to image the rail

Methodology Applied

Scientific EffectX-ray detection: X-Ray

Data Source

PatentUS10989692B2Combined passive and active method and systems to detect and measure internal flaws within metal rails

Publication Date: 2021.04.27 RAILPOD INC

AI summary

This invention utilizes two sensing technologies in combination with or in isolation of an automated inspection vehicle to conduct inspections of internal rail flaws in steel railroad track. A vehicle equipped with X-radiation sensing is used as a secondary method to assess the deviations in magnetic fields that are sensed by a primary sensor consisting of a single or multiple magnetometers. The magnetometers sense changes in magnetic field that are correlated to the flaws inside the steel rail. The combination of technologies improves the probability to detect railroad flaws and offers the ability to accurately track and monitor flaws.