Train Occupancy Range Determination for Backward Position Correction
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Solution Overview
Problem
The existing Communications-Based Train Control (CBTC) system faces issues with train position correction using correction coils, leading to incorrect determination of train occupancy in block sections, as the train position can shift backward or forward, causing misclassification of block occupancy, resulting in potential train stoppages.
Innovation Solution
An estimated train occupancy range determination device and method that detects backward corrections in train position and maintains the occupancy range based on the position before correction until the latest position reaches the pre-correction state, preventing shifts across block section boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If train position is corrected backward using correction coil, then measurement precision is improved, but occupancy determination reliability deteriorates due to block section boundary crossing
Solution Approach 1:
The system performs preliminary action by determining and storing the train occupancy range before position correction occurs. When backward correction is detected, the system maintains the pre-correction occupancy range determination, preventing the occupancy status from changing due to position correction. This ensures that the occupancy determination reflects the actual physical state of train occupancy rather than corrected position data.
2Measurement precision
If train position is corrected forward using correction coil, then measurement precision is improved, but occupancy determination reliability deteriorates due to block section boundary crossing
Solution Approach 1:
The system determines and stores the train occupancy range before position correction occurs. When forward correction is detected, the system maintains the pre-correction occupancy range determination, preventing the occupancy status from changing due to position correction. This ensures occupancy determination reflects the actual physical state rather than corrected position data.
3Measurement precision
If train position correction is applied, then measurement precision is improved, but device complexity increases due to additional correction coil communication and detection mechanisms
Solution Approach 1:
The system creates a copy of the occupancy range determination made before position correction. Instead of recalculating occupancy after correction, the system stores and reuses the pre-correction occupancy determination when correction is detected. This copying approach maintains measurement precision while avoiding the complexity of implementing and managing dynamic occupancy recalculation mechanisms.
Data Source
AI summary
An onboard system measures the train position by measuring the rotational speed of a tacho-generator, determines an estimated train occupancy range (in which the train may be present) using the train position, and transmits the estimated train occupancy range to a ground system. The onboard system corrects the train position based on the results of communication with a correction coil when the train has passed through the installation point of a correction coil. When the train position has been shifted backward as a result of correction that utilizes the correction coil, the onboard system determines and transmits the estimated train occupancy range based on the train position immediately before correction until the latest train position reaches the train position immediately before correction, and determines and transmits the estimated train occupancy range based on the latest train position after the latest train position has reached the train position immediately before correction.