CRC Verification for Train Control Data Integrity

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Solution Overview

Problem

Conventional positive train control (PTC) systems face hazards due to data normalization and train association issues, leading to incorrect enforcement of safety-critical instructions, as the geographic Back Office Server (G BOS) may alter enforceable instruction data and fail to associate it with the correct trains during transmission.

Innovation Solution

An independent process, the Individual and Composite CRC Calculator (IC3), is implemented to verify the normalization and train association of enforceable instruction data by generating Individual and Composite CRCs, ensuring data integrity and correct transmission to the on-board system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the G BOS normalizes enforceable instruction data into a common format, then data compatibility is improved, but data integrity deteriorates due to potential alterations during normalization

Engineering Contradiction:

Improvedata compatibilityVSAvoiddata integrity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system performs preliminary actions by calculating and storing the original CRC value from CAD data before normalization occurs in the G BOS. This pre-calculated CRC serves as a reference point that allows verification of data integrity after normalization, ensuring that the normalization process does not inadvertently alter critical enforceable instruction data.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanisms by comparing the original CRC value (calculated from raw CAD data) with a newly calculated CRC value (derived from normalized G BOS data). This feedback loop enables the system to detect any unintended alterations during normalization and trigger appropriate error handling or corrective actions, thereby maintaining data integrity while preserving compatibility benefits.

Inventive Principle:

Principle #23Feedback

2Productivity

If the G BOS associates enforceable instructions with trains based on stored associations, then operational efficiency is improved, but association accuracy deteriorates due to potential incorrect matching

Engineering Contradiction:

Improveoperational efficiencyVSAvoidassociation accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system calculates and stores CRC values from original CAD data before the G BOS performs train association. This preliminary CRC calculation creates a verification benchmark that can be used afterward to confirm that the correct enforceable instructions were associated with the correct trains, thereby maintaining association accuracy while preserving operational efficiency.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system replaces reliance on potentially error-prone stored associations with a cryptographic verification mechanism based on CRC checks. Instead of trusting the G BOS's association logic alone, the system uses mathematical checksums to objectively verify whether the correct data was associated with the correct train, substituting mechanical association processes with more reliable computational verification.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If conventional PTC systems transmit enforceable instructions without independent verification, then system complexity is reduced, but safety deteriorates due to undetected data corruption

Engineering Contradiction:

Improvesystem complexityVSAvoidsafety

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system performs preliminary CRC calculations on original CAD data before transmission and normalization processes. This advance preparation creates verification references that enable later safety checks without requiring complex real-time verification systems, thus maintaining relatively simple system architecture while significantly improving safety through detectable data integrity verification.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The CRC verification mechanism acts as an intermediary layer between data transmission and enforcement. Rather than requiring complex integrated verification systems throughout the transmission chain, the CRC checksums serve as independent mediators that objectively verify data integrity at key points, simplifying the overall system while enhancing safety through this intermediate verification step.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11827259B2Method and system for transmitting enforceable instructions in vehicle control systems

Publication Date: 2023.11.28 WABTEC HLDG CORP

AI summary

A method and a system for transmitting enforceable instructions in a vehicle control (VC) system includes receiving, by a cyclic redundancy check (CRC) calculator, at least one enforceable instruction from vehicle systems. The CRC calculator calculates at least one enforceable instruction CRC based at least partly on the at least one enforceable instruction and transmits the at least one enforceable instruction CRC to a back office server of the VC system and/or an on-board system of a vehicle. Methods for cyclic redundancy check (CRC) hazard mitigation in a vehicle control (VC) system and verifying enforceable instruction data on-board a vehicle are also disclosed.