Programmable Track Circuit Cards for Railroad Signal Isolation
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Solution Overview
Problem
Existing track circuit systems require multiple versions of transmitter and receiver circuit cards to operate on different frequencies and codes, leading to inventory management challenges and potential misinterpretation of spurious signals in dense track areas.
Innovation Solution
User-programmable transmitter and receiver circuit cards capable of generating and detecting 16 frequencies and 256 codes, allowing for dynamic code selection and use of a single card type, along with a decoding algorithm for FSK communications to prevent misinterpretation of signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple versions of transmitter and receiver circuit cards are used to operate on different frequencies and codes, then the track circuit can operate in close proximity without signal interference, but the inventory management becomes complex and costly
Solution Approach 1:
The patent applies universality by designing a single circuit card that can perform multiple functions through programmability. The circuit card can be programmed to operate at different frequencies and codes, eliminating the need for multiple hardware versions. This allows one card type to replace what previously required 16 different transmitter cards and 16 different receiver cards, directly reducing inventory complexity while maintaining signal discrimination capability across different track blocks
Solution Approach 2:
The patent utilizes parameter changes by allowing the circuit card to dynamically adjust its operating parameters (frequency and code) through programming rather than requiring physical hardware changes. This enables the same hardware platform to adapt to different operational requirements by changing software parameters, thereby resolving the contradiction between maintaining multiple frequency/code capabilities and reducing inventory variety
2Reliability
If multiple versions of transmitter and receiver circuit cards are used for different frequencies, then signal interference between adjacent blocks is prevented, but the cost of stocking and replacing cards increases
Solution Approach 1:
The patent implements universality by creating a single circuit card design that can perform the functions of multiple specialized cards. Through programmable frequency and code selection, one universal card type can replace the previous requirement for 16 different transmitter cards and 16 different receiver cards, directly reducing the quantity of different card types needed while maintaining the ability to isolate signals between adjacent blocks
Solution Approach 2:
The patent employs parameter changes to enable a single card to assume different operational identities. By programmably changing the frequency and code parameters, the card can be configured for different track blocks, eliminating the need to maintain inventory of multiple specialized card versions while preserving signal isolation capabilities
3Productivity
If spurious signals from adjacent blocks are not filtered out, then the receiver can detect all signals, but misinterpretation of signals occurs in dense track areas
Solution Approach 1:
The patent introduces an intermediary filtering mechanism in the form of programmable code identification. The receiver card can be programmed to recognize only specific codes associated with its designated track block, acting as an intermediary filter that allows legitimate signals from the correct block to pass while blocking spurious signals from adjacent blocks. This resolves the contradiction by enabling selective detection based on code matching
4Reliability
If physical communications lines are used for data transmission, then reliable communication is achieved, but the infrastructure cost and complexity increase
Solution Approach 1:
The patent applies mechanics substitution by replacing the mechanical/physical communications infrastructure (wires, cables, racks) with an electromagnetic field-based system. Data is transmitted through the track rails using electromagnetic signals modulated with unique codes, eliminating the need for separate physical communication lines while maintaining reliable data transmission capability between track blocks
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
Reduces inventory needs by allowing a single card type for each, enables information transmission along tracks, and prevents misinterpretation of signals, facilitating longer-distance data transmission and reducing the need for physical communications lines.
Implementation Method 1
the transmitter configured to transmit an AC signal through the track rails
Implementation Method 2
the receiver connected to the rails at the other end of the block and configured to detect the signal
Implementation Method 3
When a train is present in a block of track monitored by a track circuit, the train shunts, or shorts, the two rails
Implementation Method 4
The carrier signal is modulated by the code using a FSK technique
Data Source
AI summary
An overlay track circuit is used to transmit information through a block of railroad tracks. In one embodiment, one of a plurality of codes assigned to a receiver/transmitter pair are used to represent each information segment (which may be one or more bits) of an information signal. In another embodiment, bits of the information signal are transmitted between periodic repetitions of a code associated with the transmitter/receiver pair. The modulation may be performed using a frequency shift key technique. Track circuits may be connected to relay information between adjacent blocks of track.