Rail Track Correction Using Modulated Infrared Light
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Solution Overview
Problem
Existing rail track correction systems are inefficient due to external influences such as ambient light affecting light-based reference systems and weather conditions impacting tensioned wires, leading to inaccuracies in geometric alignment and reduced efficiency in surfacing and lining operations.
Innovation Solution
A projector device with a Fresnel lens and infrared LEDs is positioned on a rail vehicle, emitting a modulated light beam that is received by corresponding devices on another vehicle, ensuring uniform light intensity and frequency, thereby improving geometric triangulation and correction calculations, while shadow boards assist in lifting and aligning the track.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light beams or lasers are used for reference systems, then geometric measurement capability is provided, but ambient light interferes with receiver detection accuracy
Solution Approach 1:
The patent applies periodic action by modulating the light source at a specific frequency (e.g., 1 kHz square wave modulation). This allows receivers to distinguish the reference light signal from ambient light through frequency filtering, thereby maintaining measurement precision while eliminating ambient light interference. The modulated light creates a time-varying signal that can be selectively detected against the background of unmodulated ambient light.
Solution Approach 2:
The patent utilizes color changes by employing infrared light (wavelengths outside human visible range) and potentially filtering specific wavelengths. Receivers are tuned to detect only specific infrared frequencies emitted by the modulated light source, effectively ignoring ambient visible light. This wavelength-specific detection approach resolves the contradiction by making the measurement system insensitive to ambient light conditions.
2Measurement precision
If tensioned wires are used for reference systems, then geometric reference is established, but wind and weather affect wire stability
Solution Approach 1:
The patent replaces the mechanical wire-based reference system with an optical system using light beams and receivers. This substitution eliminates the mechanical components (wires) that are susceptible to wind and weather effects. The optical system uses electromagnetic radiation that can be transmitted through air without being physically disturbed by environmental conditions, thereby maintaining measurement precision while removing weather-related instability.
3Measurement precision
If receiver pairs are spaced apart from the rail maintenance vehicle, then geometric triangulation is enabled, but light frequency detection becomes unreliable
Solution Approach 1:
The patent applies periodic action through frequency modulation of the light source (e.g., 1 kHz modulation). This allows receivers spaced apart from the maintenance vehicle to reliably detect the reference signal by filtering for the specific modulated frequency. The periodic modulation creates a distinctive temporal signature that can be detected reliably over distance, enabling both geometric triangulation and reliable frequency detection simultaneously.
Solution Approach 2:
The patent implements preliminary action by pre-modulating the light source with a known frequency pattern before transmission. This preliminary encoding of the signal allows receivers at any distance to reliably detect and decode the reference information by looking for the predetermined modulation frequency, thus ensuring detection reliability regardless of the spacing between receiver and vehicle.
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
This system enhances the accuracy and efficiency of rail track corrections by minimizing external interference and ensuring consistent light reception, allowing for precise geometric adjustments and improved track alignment.
Implementation Method 1
The projector may include a Fresnel lens and a plurality of light emitting diodes (LEDs) arranged to emit a light beam. In some embodiments, the LEDs are infrared LEDs and the Fresnel lens is replaced with a convex lens or other optical lens that cooperates with the LEDs to collimate the light source
Implementation Method 2
The light beam is then modulated in such a manner that the receivers can detect the light source. For example, the light emitted from the projector device may be modulated in a range of between about 50 Hz and 2200 Hz.
Data Source
AI summary
Systems and methods for use in carrying out rail track corrections. A projector device is positioned on a vehicle deployed ahead of a rail maintenance vehicle and includes a Fresnel lens and a plurality of light emitting diodes arranged to provide a light beam that provides a uniform “spot.” The projector device modulates the light beam in such a manner that a pair of receiver receivers disposed on the rail maintenance vehicle can detect the light source and the light intensity and frequency of wavelength of light received into each receiver of a receiver pair is substantially equal. Recorded values may be used to triangulate the geometry of the section of track being worked, while a computer compares the previous section of track already corrected to the current section and makes calculations for desired corrections to be made at work heads on the rail maintenance vehicle.