Train Clearance Detection Using GPS Position Comparison
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Solution Overview
Problem
Railroad operations face challenges in determining when the rear of a first train has cleared a track intersection to ensure safe passage of a second train, particularly in the absence of personnel to visually confirm clearance, and existing methods are unreliable without accurate knowledge of train length.
Innovation Solution
A method using GPS systems and processors in the lead and rear vehicles of a train, connected via a communication channel, to determine the position of the last car relative to a marker, allowing for safe passage of the second train by comparing GPS data and generating a signal when the vehicles are within a predetermined distance of each other.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If personnel visually confirm clearance from the final car, then clearance determination is achieved, but personnel availability and safety are compromised
Solution Approach 1:
The train itself determines its own clearance status through GPS receivers on the lead and rear vehicles, eliminating the need for external personnel. The system automatically compares GPS coordinates to determine when the rear vehicle has cleared the intersection, making the train self-monitoring for clearance determination.
Solution Approach 2:
The patent replaces the mechanical/visual method of personnel observation with an electronic GPS-based detection system. GPS receivers and coordinate comparison automatically determine clearance status, substituting human visual confirmation with automated electronic measurement.
2Measurement precision
If odometer and known train length are used to determine last car position, then clearance can be calculated, but accuracy depends on accurate train length knowledge
Solution Approach 1:
The patent replaces the calculation-based method (odometer readings combined with known train length) with direct GPS coordinate measurement. By using GPS receivers on both the lead and rear vehicles, the system directly measures the actual position of the rear vehicle without relying on calculated train length, eliminating errors from inaccurate length data.
Solution Approach 2:
The GPS coordinate comparison acts as an intermediary that directly links the lead vehicle's position to the rear vehicle's position. Instead of using train length as an intermediary parameter that introduces error, the system uses GPS coordinates as the direct measurement intermediary, providing more accurate position determination.
3Adaptability or versatility
If GPS systems are installed in both lead and rear vehicles, then clearance determination is independent of train length knowledge, but device complexity increases
Solution Approach 1:
The GPS receivers in the lead and rear vehicles serve multiple functions: they track the train's movement for clearance determination, provide positioning data for safety monitoring, and enable the system to adapt to varying train compositions without requiring reconfiguration or accurate train length data. This multi-functionality justifies the added device complexity.
Data Source
AI summary
A method of determining when a first train has cleared an intersection a distance to permit travel of a second train through the intersection without risk of collision or contact includes: (a) sampling first GPS data corresponding to a location of a lead vehicle of the first train travelling on a first track when the lead vehicle passes proximate a marker; (b) sampling second GPS data corresponding to a location of a last vehicle of the first train moving on the first track; (c) comparing the second GPS data and the first GPS data: (d) repeating steps (b)-(c) until the location corresponding to the first GPS data and the location corresponding to the second GPS data are within a predetermined distance of each other, and (e) generating a signal when the locations are within the predetermined distance.