Railway Vehicle Movement Profile Classification for Track Circuit Accuracy
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Solution Overview
Problem
Existing track circuit systems face errors in determining the location of railway vehicles due to acceleration or deceleration, which introduces bias in the relationship between transmitted current and vehicle position, affecting the accuracy of virtual signaling in advanced train control systems.
Innovation Solution
A method that involves obtaining a railway vehicle movement profile from measured transmitted currents, normalizing it, extracting features, determining distances relative to centroids of predefined movement profiles, and assigning the profile to the closest centroid type, using techniques like Dynamic Time Warping, exponential filtering, and k-means clustering to classify the movement type as accelerating, decelerating, or constant speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If track circuit data is used to locate the position of a train within a signaled block, then the position can be determined for virtual signaling, but errors are introduced when the railway vehicle accelerates or decelerates, reducing measurement precision
Solution Approach 1:
The system dynamically adapts its operation based on the detected movement profile type. When acceleration or deceleration is detected, the system adjusts its position determination strategy by using interpolated positions from constant-speed segments rather than directly using track circuit measurements during transient phases. This dynamic adaptation resolves the contradiction by maintaining reliability during varying speed conditions while preserving measurement precision during constant-speed operation.
Solution Approach 2:
The system changes the operational parameters of position determination based on the movement profile. During constant-speed phases, it uses direct track circuit measurements with standard interpolation. During acceleration or deceleration phases, it switches to using pre-calculated positions from constant-speed segments, effectively changing the determination parameter to avoid bias introduction and maintain both precision and reliability.
2Ease of operation
If the relationship between track circuit data and train position is determined using standard interpolation, then position can be calculated, but bias is introduced when the railway vehicle accelerates or decelerates significantly
Solution Approach 1:
The system dynamically selects the appropriate position calculation method based on the movement profile type. During constant-speed operation, simple linear interpolation is used for ease of operation. During acceleration or deceleration, the system dynamically switches to a more complex method that uses interpolated positions from constant-speed segments, thereby maintaining measurement precision without permanently complicating the operation.
Solution Approach 2:
The interpolation parameter changes based on movement conditions. The system uses different interpolation strategies: standard linear interpolation during constant-speed phases for simplicity, and adjusted interpolation using reference positions from constant-speed segments during acceleration or deceleration phases to maintain accuracy. This parameter adaptation resolves the contradiction between operational simplicity and measurement precision.
Data Source
AI summary
A computer-readable non-transitory storage medium including instructions, which when executed by a computer, cause the computer to carry out the followings: obtaining a railway vehicle movement profile, wherein the railway vehicle movement profile includes a sequence of measured transmitted currents of a transceiver of a track circuit with respect to time; normalizing the railway vehicle movement profile; extracting one or more features from the normalized railway vehicle movement profile; determining a distance of the extracted features with respect to each centroid of a railway vehicle movement profile type determined in a classification process; and assigning the railway vehicle movement profile to the railway vehicle movement profile type with a closest centroid.