Fibre Optic Distributed Acoustic Sensing for Train Separation Detection
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Solution Overview
Problem
Existing train separation detection methods are inadequate, especially in the absence of fail-safe braking systems, as they fail to reliably detect decoupling events in long trains, posing a significant hazard due to undetected decoupled sections that can cause collisions or derailments.
Innovation Solution
The use of fibre optic distributed acoustic sensing (DAS) to monitor acoustic signals along a railway, identifying distinct parts of a train by analyzing acoustic responses from optical fibres deployed alongside the track, allowing for the detection of train separation by determining the distance between the front and rear of the train and identifying changes beyond a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If traditional train control systems relying on GPS locators and inertial guidance systems are used, then the front position of the train can be tracked, but the system cannot detect train separation events
Solution Approach 1:
The patent replaces traditional mechanical and electronic train monitoring systems (GPS locators, inertial guidance systems, transceivers) with an acoustic sensing system. Optical fibres are embedded in the train cars to detect acoustic signals generated by wheel-rail interactions, providing a fundamentally different approach to train monitoring that can detect separations without relying on complex positioning systems.
Solution Approach 2:
The patent introduces optical fibres as intermediary sensing elements embedded within the train structure. These fibres act as mediators that directly sense acoustic vibrations from wheel-rail interactions and transmit this information to the monitoring system, enabling detection of train separation events without requiring complex external positioning infrastructure.
2Reliability
If fail-safe braking systems are implemented, then automatic brake application occurs upon decoupling, but the system may not be available or defective in parts of the train
Solution Approach 1:
The patent divides the train into multiple acoustic sensing zones by embedding optical fibres in individual train cars. Each fibre segment independently monitors acoustic signals from its associated car's wheel-rail interactions, enabling localized detection of separation events. This segmentation allows the system to function even if only portions of the train are monitored.
Solution Approach 2:
The acoustic sensing system embedded in each train car provides self-service monitoring capability. Each car's optical fibre independently detects acoustic signals from its own wheel-rail interactions, allowing individual cars to contribute to the overall separation detection without requiring a centralized braking system or complex inter-car communication infrastructure.
3Measurement precision
If acoustic sensors are deployed along the railway to detect train separation, then separation events can be detected with high spatial resolution, but the system complexity and cost increase
Solution Approach 1:
The patent embeds optical fibres within the structure of the train cars themselves, nesting the sensing system inside the object being monitored. This eliminates the need for separate external acoustic sensor arrays along the railway, reducing overall system complexity while maintaining high spatial resolution detection capability through the distributed nature of the embedded fibres.
Solution Approach 2:
The embedded optical fibres serve multiple functions: they are both structural elements of the train car and acoustic sensing elements. This multi-functionality reduces the need for separate dedicated sensing infrastructure, thereby reducing overall system complexity while maintaining high measurement precision for train separation detection.
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
Enables reliable detection of train separation over long distances with high spatial resolution, providing early warning systems to prevent collisions and ensure safe operation, even in the absence of fail-safe braking systems, by continuously monitoring the distance between the front and rear of the train.
Implementation Method 1
fibre optic distributed acoustic sensing (DAS)... repeatedly interrogated with electromagnetic radiation to provide sensing of acoustic activity along its length... By analysing the radiation backscattered from within the fibre, the fibre can effectively be divided into a plurality of discrete sensing portions
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 which may be (but do not have to be) contiguous
Data Source
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Figure 4a~4d
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AI summary
This application describes method and apparatus for detecting train separation, where one or more railway cars/carriages (401)accidentally decouple from the rest of the train. The method involves performing distributed acoustic sensing on at least one optical fibre (104a, 104b) to provide a plurality of longitudinal acoustic sensor portions along the railway (201). The acoustic response is analysed to detect a signature indicative of a train separation. This may involve detecting acoustic events (302, 303) associated with different parts of the train and detecting when the separation between the two events exceeds a threshold amount. The method may identify the front of the train and the rear of the train and detect when the distance between the front and rear changes by more than a threshold amount and/or sounds associated with wheelsets passing track features (402) may be used to determine the intervals(T3, T4) between wheelsets of adjacent cars and determine when the interval exceeds a threshold amount. The threshold may be based on the interval (T2) between wheelsets of the same car passing the track feature.