Distributed Fibre Optic Sensing for In-Train Forces
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Solution Overview
Problem
Rail networks face challenges in monitoring and managing in-train forces during heavy braking or acceleration, which can lead to significant forces propagating through train cars, causing degradation of rolling stock and potential catastrophic failures, due to delayed braking signals and excessive coupling stress.
Innovation Solution
The method involves using distributed fibre optic sensing, specifically fibre optic distributed acoustic sensing (DAS), to detect and analyze acoustic transients along rail tracks, identifying a characteristic signature of in-train forces as a sequence of acoustic signals propagating rearwards, allowing for real-time detection and estimation of force magnitude and propagation rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sensing technologies are used to monitor rail networks, then installation and maintenance are straightforward, but achieving desired spatial resolution and scope of coverage is difficult and costly
Solution Approach 1:
The patent applies multi-functionality by using a single DAS sensing fibre to simultaneously achieve multiple sensing channels over long distances (40 km or more), providing both high spatial resolution (10m contiguous channels) and extensive coverage, replacing multiple traditional sensing systems with one unified solution
Solution Approach 2:
The patent transitions from point-based traditional sensing to distributed continuous sensing along the fibre length, effectively adding a spatial dimension to the monitoring capability, allowing simultaneous measurement at numerous locations along the rail network
2Speed
If heavy braking or acceleration is applied to trains, then travel time is reduced, but significant forces propagate through train cars causing degradation and potential catastrophic failures
Solution Approach 1:
The system performs preliminary detection of in-train forces using DAS sensors deployed along the track, identifying characteristic acoustic signatures of coupling forces before catastrophic failure occurs, enabling preventive maintenance actions to be taken in advance
Solution Approach 2:
The patent implements feedback by continuously monitoring acoustic signals from train couplings using DAS, detecting characteristic signatures of excessive forces, and providing real-time information that can trigger alerts or corrective actions to prevent damage
3Ease of operation
If in-train forces are not monitored, then operational simplicity is maintained, but degradation of rolling stock and potential catastrophic failures occur
Solution Approach 1:
The DAS system provides self-service monitoring by automatically detecting and analyzing acoustic signatures of in-train forces along the entire monitored section, eliminating the need for manual inspection while continuously enhancing safety through automated force detection and characterization
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 real-time monitoring and alerting of significant in-train forces, facilitating corrective actions and reducing maintenance costs by providing accurate data on force severity and propagation, thus enhancing safety and reducing maintenance needs.
Implementation Method 1
Fibre optic distributed acoustic sensing (DAS) is a known type of sensing where an optical fibre is deployed as a sensing fibre and repeatedly interrogated with electromagnetic radiation to provide sensing of acoustic activity along its length
Implementation Method 2
By analysing the radiation backscattered from within the fibre, the fibre can effectively be divided into a plurality of discrete sensing portions
Implementation Method 3
Within each discrete sensing portion mechanical disturbances of the fibre, for instance, strains due to incident acoustic waves, cause a variation in the properties of the radiation which is backscattered from that portion
Data Source
AI summary
This application relates to methods and apparatus for monitoring data obtained as a train (202) travels on along a rail track (201) to detect the occurrence and/or severity of any significant in-train forces, such as may be caused by heavy braking or excessive acceleration. The method involves taking a first data set corresponding to measurement signals from a plurality of channels of at least one fibre optic distributed acoustic sensor (202) having a sensing fibre (101) deployed to monitor at least part of the rail track. The first data set corresponds to measurement signals acquired as the train passes along the rail track. The method involves analysing the measurement signals to detect a first characteristic signature (402) which consists of a sequence of acoustic transients that appear to propagate rearwards along the train.