Patina Creation Device for Third Rail Wear Reduction

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Solution Overview

Problem

The frequent replacement of TRC shoes due to initial severe wear before the formation of a patina layer on the third rail is costly and inefficient, as they are a critical and expensive component with long lead times, and existing solutions fail to effectively modify mechanical properties or dimensions to enhance their duration.

Innovation Solution

A patina creation device made of a softer carbon-copper alloy material, with increased surface area and contact pressure, is used to transfer material onto the third rail, facilitating faster patina formation and reducing TRC shoe wear by 50-70% by forming a lubricity film.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a TRC shoe is used for sliding contact with the third rail, then electrical current collection is achieved, but severe initial wear occurs before patina layer formation

Engineering Contradiction:
Improveelectrical current collectionVSAvoidTRC shoe lifespan
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent applies preliminary action by using a dedicated patina creation device that operates before the main TRC shoe to pre-form the protective patina layer on the third rail. This preliminary patina formation reduces subsequent wear of the TRC shoe, extending its service life while maintaining reliable electrical contact.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If the TRC shoe material is made softer to reduce wear, then contact with the rough initial third rail is improved, but the shoe wears even faster before patina formation

Engineering Contradiction:
Improvecontact with third railVSAvoidTRC shoe duration
Core Design Contradiction:
Ease of operationVSDuration of action of moving object

Solution Approach 1:

The patent applies parameter changes by modifying the material properties of the patina creation device shoe to be softer (60-80 HB hardness) than the standard TRC shoe (100-150 HB hardness). This softer material transfers more easily to form the patina layer, while the controlled softness prevents excessive wear once the patina is formed, thus extending TRC shoe duration.

Inventive Principle:
Principle #35Parameter changes

3Duration of action of moving object

If a patina creation device is added to accelerate patina formation, then TRC shoe wear is reduced, but device complexity increases

Engineering Contradiction:
ImproveTRC shoe lifespanVSAvoidcurrent collector system complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The patent applies segmentation by separating the current collection function from the patina creation function. The patina creation device operates as a separate, dedicated component with its own shoe and actuation mechanism, allowing it to be independently controlled and replaced without affecting the main TRC shoe assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts the patina creation function from the main current collector system. The patina creation device is a removable, standalone unit that can be deployed independently to form the patina layer, then removed or repositioned, leaving the main TRC shoe assembly unchanged and simpler.

Inventive Principle:
Principle #2Taking out (Extraction)

4Productivity

If the contact pressure is increased to enhance patina formation, then the lubricity film forms faster, but the mechanical properties of the TRC shoe are compromised

Engineering Contradiction:
Improvepatina formation speedVSAvoidTRC shoe mechanical properties
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The patent applies local quality by applying different contact pressures to different components: the patina creation device shoe is designed with higher contact pressure (10-20 N/mm) to accelerate patina formation, while the main TRC shoe maintains standard contact pressure (3-5 N/mm) to preserve its mechanical properties and electrical contact quality.

Inventive Principle:
Principle #3Local quality

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 patina creation device significantly reduces the wear of TRC shoes by accelerating the formation of a lubricity film on the third rail, thereby extending the lifespan of TRC shoes and lowering overall running costs.

Implementation Method 1

The patina creation device is arranged to be consumed by friction against the third rail, thus forming a coating layer on said third rail

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The TRC shoe during the runs slides on the third rail and this sliding contact generates wear on the TRC shoe

Methodology Applied
Scientific EffectWear: Wear

Data Source

PatentEP3798086B1Patina creation device
Publication Date: 2022.11.02 ALSTOM TRANSPORT TECH SAS
  • EP3798086B1 patent drawingFigure 1
  • EP3798086B1 patent drawingFigure 2
  • EP3798086B1 patent drawingFigure 3

AI summary

A patina creation device (50) arranged to be connected to a railway car (4), and to be put in contact with a third rail (6) running in parallel to a rail (2) of a railway line on which the railway car (4) is placed, said patina creation device (50) comprising a least one bar (50a) extending along a longitudinal axis of the third rail (6) and arranged to be consumed by friction against the third rail (6), thus forming a coating layer on said third rail (6).