Patent Description:
It is common for debris and other objects to fall in railroad tracks. Such objects are obstructions that can affect the safe movement of trains, resulting in train derailment or damage to locomotives. The size of the object can greatly affect the magnitude of the disruption to a locomotive.

Traditional slide fences are installed at rockfall hazard locations to detect rockslides/falls that may impede travel along the track and cause damage to locomotives and/or injury to railroad employees. Several slide fence types and configurations can be deployed for detecting such potential hazards, but each suffers from certain pitfalls. For example, open-line wire slide fences are comprised of line wire strung end-to-end the length of the hazard area. A power source is connected to a pair of line wires and a series electrical circuit is created through each sequential line wire pair to energize a relay (closed loop principle). Falling rocks or objects break the line wire, opening the series circuit, de-energizing the relay, and indicates a hazard is detected.

Such conventional slide fences are electrically circuited based on the fail-safe (closed-loop) principle. However, slide fence hazard detection systems are prone to missed events. Sliding and falling rocks having the potential for hazardous train operations can pass between the line wires or fall pass slide fences and canopies/umbrellas undetected. For detected rockslides and falls, the conventional slide fence technology is unable to determine fallen rock size or location. Fallen rocks small in size or not impeding travel along the track that break a slide fence wire are determined as valid alarms, although they pose no danger to train operations. Additionally, the inability to determine if a detected rockslide or fall poses a valid hazard to train operation can result in false alarms causing needless train delay and reduced network velocity. False alarms not only cause needless train delay, but over time in active rock fall areas, can result in train crew complacency and can condition railway personnel to doubt the validity of slide fence alarms, thereby adding unnecessary risk to train operations.

Since some level of slide fence damage results in detecting fallen rocks, maintenance personnel must be dispatched to repair the slide fence, regardless of whether the fallen rocks are a hazard to train operations. This places maintenance personnel at increased risk while facilitating slide fence repairs during active rock-slide conditions and track traffic. Additionally, train delay is incurred pending slide fence repairs. In some cases, the rockslide can be significant enough to destroy several sections of slide fence. In these situations, it can take considerable time and manpower to rebuild a slide fence after the rocks and debris are removed. <NPL>) and <NPL>) both documents disclose a trial LIDAR fence on a particular location where fracturing shale rock in near vertical cliffs adjacent to a train track. The LIDAR fence provides a detection of obstacles on the track itself, and allows a decision of urgency required with which to send an engineer to a sometimes quite remote site. <CIT> discloses an apparatus for automatic providing a danger-signal via a mechanical movable barrier for railroads at any point along the track where trees, rocks, or land-slides might fall on the track. The signal can be displayed at any desired point of the track to indicate to the engineer that an obstruction has fallen on the track. <CIT> discloses techniques for detection of objects for railways. The presence of an object on a railroad track is detected by optically scanning a predetermined length of railroad track. The position of the object is determined and then a warning signal indicative of the presence and position of the sensed object can be generated.

The present disclosure achieves technical advantages as a Wireless Slide Fence utilizing signal reflection technology to detect rockslides and can determine the size and location of fallen rocks/objects impeding travel along the track (e.g., within <NUM> feet of the outside edge of a rail). The present disclosure solves the technological problem of determining rock size and location to validate rockslide/fall alarms to reduce false alarms. This Wireless Slide Fence can accommodate any volume of train density, gross tonnage, passenger train movement density, hazardous materials, railroad operating rules, and operating speeds. The Wireless Slide Fence can also be retrofitted to existing slide fence systems as a replacement at current slide fence locations or as a new installation at new slide fence locations.

The present disclosure improves the performance of the system itself by, generating validated alarms when fallen rocks/objects satisfy the size criteria and are located in an area hazardous to train operations. In one exemplary embodiment, a loitering time can be implemented to validate object detections to reduce false positives due to transient objects such as migrating animals. In another exemplary embodiment, video camera can be utilized to further validate an activation notification. In another exemplary embodiment, when a validated alarm is generated, the Wireless Slide Fence can provide an output to a train control system or a signal system to indicate a hazard is detected and transmit a slide fence activation notification to the train dispatcher. The Wireless Slide Fence notification can be removed when the object is removed from the tracks. Thus, risk to maintenance personnel is reduced as rockfall detection does not require destruction of equipment that is characteristic of the wired slide fence. Risk to personnel is mitigated during repair of any portions of the Wireless Slide Fence damaged by rockfall as repair activities are limited to replacing the affected Wireless Slide Fence Obstacle Detection (OD) unit and uploading the pertinent configuration onto the sensor.

It is an object of the disclosure to provide a wireless slide fence system configured to detect an object capable of obstructing train passage along a track. It is a further object of the disclosure to provide a wireless slide fence system configured to generate an indication of an obstacle when an object capable of obstructing train passage is identified. It is a further object of the disclosure to provide a computer-implemented method for generating an indication of an obstacle when an object capable of obstructing train passage is identified.

The present invention is defined by features of the independent claims. The dependent claims define preferred embodiments of the invention.

In one exemplary embodiment, a wireless slide fence system configured to detect an object capable of obstructing train passage along a track, includes: a plurality of obstacle detection units configured to transmit a signal proximate a railroad track and receive a reflection of the signal from an object proximate the railroad track, wherein one or more obstacle detection units detect an object in a detection zone and generate a detection alert, when the reflected signal is received; and a vital logic controller operably coupled to the obstacle detection units and configured to control the obstacle detection units, receive the alert, and transmit an indication of an obstacle to a signal system or train control system to reduce its speed or stop. The signal transmitted by the plurality of obstacle detection units can be an acoustic signal, an optical signal, a RADAR signal, or any other suitable signal. Each of the plurality of obstacle detection units can have a field of view different from the other obstacle detection units. Adjacent fields of view can at least partially overlap. Obstacle detection units can generate the detection alert only if the object is still detected after a predetermined loitering time. The object can be continuously detected during the predetermined loitering time to be determined a valid alert. The obstacle detection units can include shutters configured to open and close to protect the obstacle detection unit from damage. The vital logic controller can open and close the shutters.

In another exemplary embodiment, a wireless slide fence system can be configured to generate an indication of an obstacle when an object capable of obstructing train passage is identified, including: a vital logic controller including computer-executable instructions that when executed cause the controller to: receive an obstacle detection alert from an obstacle detection unit for an object in a detection zone proximate a railroad track; determine whether the object is in the detection zone after a predetermined loitering time; transmit an indication of an obstacle to a signal system or train control system via an encrypted network if the object is in the detection zone after the predetermined loitering time; close shutters disposed on the obstacle detection unit to protect a transceiver for a predetermined period; open the shutters for a predetermined scan period to scan the detection zone for the object; determine whether the object is in the detection zone after a predetermined scan period; clear the alarm state and the indication of the obstacle to the train. The railroad signaling system can be programmed to flash red to indicate to a train that it must proceed at restricted speed and stop short of any obstruction. The vital logic controller can transmit the indication directly to the train's onboard positive train control (PTC) system or a signal system. All object detection units can continuously report a clear state over a clear time period during the scan period. The clear time period can be at least a portion of the rscan period.

In another exemplary embodiment, a computer-implemented method for generating an indication of an obstacle when an object capable of obstructing train passage is identified, the computer-implemented method comprising: receiving an obstacle detection alert from an obstacle detection unit for an object in a detection zone proximate a railroad track; determining whether the object is in the detection zone after a predetermined loitering time; transmitting an indication of an obstacle to a train control system or a signaling system via an encrypted network if the object is in the detection zone after the predetermined loitering time; closing shutters disposed on the obstacle detection unit to protect a transceiver for a predetermined period; opening the shutters for a predetermined scan period to scan the detection zone for an object; determining whether the object is in the detection zone after a predetermined scan period; clearing the alarm state and the indication of the obstacle to the train control system via an encrypted network. The train signaling system can be programmed to flash red to indicate to a train that it must proceed at restricted speed and stop short of any obstruction. The vital logic controller can transmit the indication directly to the train's onboard positive train control (PTC) system or the signaling system. All object detection units can continuously report a clear state over a clear time period during the scan period. The clear time period can be at least a portion of the scan period.

The preferred version of the disclosure presented in the following written description and the various features and advantageous details thereof, are explained more fully with reference to the non-limiting examples included in the accompanying drawings and as detailed in the description, which follows. Descriptions of well-known components have been omitted so to not unnecessarily obscure the principle features described herein. The examples used in the following description are intended to facilitate an understanding of the ways in which the disclosure can be implemented and practiced. Accordingly, these examples should not be construed as limiting the scope of the claims.

<FIG> shows a schematic view of a Wireless Slide Fence system <NUM>, in accordance with one exemplary embodiment of the present disclosure. The Wireless Slide Fence <NUM> can include a Obstacle detection (OD) unit <NUM>, an alarm relay <NUM>, a trouble output relay <NUM>, a vital alarm relay <NUM>, a vital relay contact <NUM>, a Vital Logic Controller (VLC) <NUM>, and a signal system and/or train control system <NUM>.

The aforementioned system components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> can be communicably coupled to each other via a network, such as the Internet, intranet, system bus, or other suitable network, wired or wireless. The communication can be encrypted, unencrypted, over a VPN tunnel, or transmitted over other suitable communication means. The network can be WAN, LAN, PAN, or other suitable network. The network communication between the system components <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, can be encrypted using PGP, Blowfish, AES, 3DES, HTTPS, or other suitable encryption. The network communication can occur via application programming interface (API), ANSI-X12, Ethernet, Wi-Fi, Bluetooth, PCI-Express, USB, or other suitable communication protocol. Additionally, databases having obstacle detection or control data can be operably coupled to the system components VLC <NUM>.

The Obstacle detection unit <NUM> can be a sensor that can detect fallen rocks or other objects on or near a railway line. The Obstacle detection unit <NUM> can be an area sensor used to detect objects by emitting laser beams, optical signals, acoustic signals, or other suitable signals, and measure the time required for reflected beams to be received by a receiver. In one exemplary embodiment, the Obstacle detection unit <NUM> can have a detection area of approximately <NUM> feet over <NUM>-degree arc. In another exemplary embodiment, the Obstacle detection unit <NUM> can incorporate IEC <NUM>-<NUM> defined Class <NUM> laser beams (IEC), imposing a detection plane covering above the railroad tracks.

In another exemplary embodiment, each Obstacle detection unit <NUM> can include a transmitter and a receiver, a transceiver, or other suitable communication device. In another exemplary embodiment, the transmitter and receiver can be mounted together in a single sensor housing. In another embodiment, transmitter and receiver can be mounted in separate housings. In another exemplary embodiment, the Obstacle detection unit <NUM> can include separate acoustic transducers for each transmitter and receiver. In another exemplary embodiment, a single acoustic transducer can be used for both transmitting a signal and receiving its reflection. In another exemplary embodiment, Obstacle detection unit <NUM> can include a micropower impulse radar (MIR) device. In yet another exemplary embodiment, Obstacle detection unit <NUM> can include a microwave transceiver device. The Obstacle detection unit <NUM> can include a small integrated antenna and electronic interface board. In another exemplary embodiment, the Obstacle detection unit <NUM> can include a heating element to ensure the Obstacle detection unit <NUM> can function without impairment due to ice or fog.

The Obstacle detection unit <NUM> can detect an object by emitting signals (e.g. laser beams, acoustic signals, or other suitable signals) via the transmitter/transceiver at an object, and measuring the time required for the emitted signals to be reflected by the object and received by the receiver/transceiver. The Obstacle detection unit <NUM> can include a processor and/or controller for controlling the various components of the Obstacle detection unit <NUM>. In one exemplary embodiment, the Obstacle detection unit <NUM> can determine an object detection via the processor and transmit the detection to the VLC <NUM>. In another exemplary embodiment, the Obstacle detection unit <NUM> can transmit the received data to the VLC <NUM> and the VLC <NUM> can determine whether an object was detected by the Obstacle detection unit <NUM>.

Each Obstacle detection unit <NUM> housing can include a motorized shutter that can be activated under specific conditions to protect the Obstacle detection unit <NUM> from contamination or damage. In one exemplary embodiment, the VLC <NUM> is "vital" because it has a probability of failing in an unsafe state of <NUM>-<NUM> (one failure in one billion events). Alternatively, the VLC <NUM> can have any reliability/failure probability rating required for a particular application. For example, VLC <NUM> can transmit a signal to each Obstacle detection unit <NUM> to close the shutter when a train is within a particular area or detection zone. In one exemplary embodiment, an Obstacle detection unit <NUM> can detect the train and transmit a detection signal to VLC <NUM>, which in turn generates a shutter close signal to each Obstacle detection unit <NUM>. Each Obstacle detection unit <NUM> can be mounted on posts proximate the railroad tracks with sufficient distance to transmit a signal and receive its reflection with sufficient signal fidelity to detect the size and location of an object on or near the railroad tracks. The Obstacle detection unit <NUM> can have external elements to adjust the horizontal and vertical alignment of the Obstacle detection unit <NUM>. In one exemplary embodiment, the output of the Obstacle detection unit <NUM> transmitter can be reduced, and the sensitivity of the Obstacle detection unit <NUM> receiver can be increased by VLC <NUM>. In another exemplary embodiment, the VLC <NUM> can include additional control logic or an interface to external control logic. The normal state of the motorized shutter is in the open position to allow for active scanning of the detection area. The movement of the motorized shutter can be controlled by a linear actuator that can receive control signals from the Obstacle detection unit <NUM> processor or the VLC <NUM> to open or close the shutter.

One or more Obstacle detection units <NUM> can be operably coupled with the VLC <NUM> to form a slide fence network to detect hazards. The VLC <NUM> can provide an interface between the Obstacle detection units <NUM> and the Signal System/Train Control System <NUM>. Additionally, the VLC <NUM> can detect train movements, perform diagnostic checks, and determine when to generate an alarm. In one exemplary embodiment, with no alarm indications from all Obstacle detection units <NUM>, the VLC <NUM> can allow trains to proceed at a maximum authorized speed. When a train is present in the detection zone, the VLC <NUM> can drive actuators to close shutters and protect the sensors from contamination Every time the shutters are driven closed, the VLC <NUM> can perform a safety check to ensure the Obstacle detection units <NUM> are operational. If any safety checks fail, the VLC <NUM> can put the signal system in safe state.

In one exemplary embodiment, two or more Obstacle detection units <NUM> can continuously monitor any predetermined area of the railroad track, the monitored area of the railroad track can be designated a detection zone. In another exemplary embodiment, the Obstacle detection units <NUM> can be coupled in parallel so that detection by one Obstacle detection unit <NUM> is sufficient to generate an object detection indication. In another exemplary embodiment a camera can be disposed in the Obstacle detection unit <NUM> to provide visual confirmation of an object on or around the train tracks. Alternatively, the camera can be disposed proximate the Obstacle detection unit <NUM>, yet operably coupled to the VLC <NUM>. The use of a video camera to corroborate the indication of a detection of an object on or near the train tracks is optional.

In one exemplary embodiment, each Obstacle detection unit <NUM> can convey the presence of an object by activating an alarm relay <NUM> that can be tied externally to the coils of a vital alarm relay <NUM>. The contacts of a trouble output relay <NUM> can be wired in series with the alarm relay <NUM> and the vital alarm relay <NUM>. In one exemplary embodiment, the vital alarm relay108 can be the second relay of the same hardware as the alarm relay <NUM>. The trouble output relay <NUM> can de-energize when the Obstacle detection unit <NUM> determines that its scanning surface has been completely obfuscated (e.g. from a closed shutter or soiled scanning window) by identifying a high proportion of reflected signals (e.g., optical beams, acoustic signals, etc.) at its receiver. The vital relay contact <NUM> can control an input into the VLC <NUM>. In another exemplary embodiment, once the VLC <NUM> ceases to receive the input from the vital relay contact <NUM>, the detection information can be conveyed to the signal system/train control system <NUM>.

<FIG> shows a schematic view of a Wireless Slide Fence system installation <NUM>, in accordance with one exemplary embodiment of the present disclosure. Wireless Slide Fence system installation <NUM> can include train tracks <NUM>, Obstacle detection unit <NUM>, a detection zone <NUM>, an equipment shelter <NUM>, having a Vital Logic Controller (VLC) <NUM> and power source <NUM>, with access to a network <NUM>.

Obstacle detection units <NUM> can be mounted onto poles/posts disposed proximate to the tracks <NUM>. In one exemplary embodiment, the Obstacle detection unit <NUM> are disposed on the poles at a height allowing for a <NUM>-inch diameter object to be reliably detected. In another exemplary embodiment, a plurality of Obstacle detection units <NUM> can be spaced at a maximum of <NUM> feet from each other. Each Obstacle detection unit <NUM> can have a unique identifier to identify each Obstacle detection unit <NUM>. The location of each Obstacle detection unit <NUM> can be stored in the VLC <NUM> or other suitable device to assist in object location. In another exemplary embodiment, each Obstacle detection unit <NUM> can emit a laser beam, acoustic signal, optical signal, or other suitable signal to detect objects within a <NUM>-foot radius from the center of the mounting post.

The Obstacle detection unit <NUM> or the VLC <NUM> can detect the presence of an object on or near the tracks <NUM>. In one exemplary embodiment, the detection is based upon the size of the object. In another exemplary embodiment, the detection is based upon the location of the object. In yet another exemplary embodiment, the detection is based upon the size and location of the object. The size of an object on or near the tracks can trigger a detection. For example, considering a typical (<NUM>-<NUM> pound) rail height of slightly over <NUM> inches, the maximum allowed locomotive snow plow / pilot clearance of <NUM> inches above top of rail and typical locomotive under-body clearance of approximately <NUM> inches above top of rail, a boulder with a height of approximately <NUM> inches or less would likely pass under the train without resulting in a derailment. In one exemplary embodiment, the Obstacle detection unit <NUM> or the VLC <NUM> can calculate the height and width of an object on or near the tracks <NUM>, given the data received by the Obstacle detection unit <NUM>. In another exemplary embodiment, the volume of the object can be determined using the reflection of the received signals. In another exemplary embodiment, the volume of the object can be determined by mathematically approximating the object as an ellipsoid, using the height (major axis) and width (minor axis) of the object as received by the Obstacle detection unit <NUM>. The location of the object can be determined by the Obstacle detection units <NUM> that detect an object, using the predetermined location of each Obstacle detection unit <NUM>.

The spacing along the length of track through the detection zone <NUM> ensures the zone <NUM> can be monitored by a minimum of two LIDAR OD units or redundancy. In one exemplary embodiment, during installation, each LIDAR OD Unit <NUM> can be used to delineate the detection zone <NUM> prescribed by the tracks <NUM>. In one exemplary embodiment, each LIDAR OD Unit <NUM> can have its own field of view. The LIDAR OD Unit <NUM> can be placed such that a first LIDAR OD Unit <NUM> can overlap a second LIDAR OD Unit <NUM> field of view, such that at least two LIDAR OD Units <NUM> are capable of detecting an object in the detection zone <NUM>, save the two LIDAR OD Units <NUM> on each end of the detection zone <NUM>. the two LIDAR OD Units <NUM> on each end of the detection zone <NUM> only have overlap for half of their fields of view. To preserve redundancy across the entire slide fence, the LIDAR OD units at either edge of the slide fence detection zone can only monitor the area overlapped with its adjacent sensor. Alternatively, no field of view overlap (redundancy) can be implemented with a cost of increased risk to operations and personnel. An audio frequency overlay (AFO) track circuit can be installed the length of detection zone <NUM>. Shunting the AFO track circuit can prepare the Wireless OD system for train passage.

The Obstacle detection units <NUM> can be operably coupled to the VLC <NUM> and the power source <NUM> disposed in the equipment shelter <NUM> by infrastructure such as, underground cables, above ground cables, or wireless network, among other suitable communication means. In one exemplary embodiment, the power source <NUM> can utilize the infrastructure to provide power to the Obstacle detection units <NUM> and associated equipment, such as shutters, actuators, heaters, transmitters, receivers, controllers, processors, or other suitable devices. In another exemplary embodiment, the VLC <NUM> can utilize the infrastructure to effect shutter control, transmitter control, receiver control, relay control, and system test control of the Obstacle detection units <NUM>. In another exemplary embodiment, diagnostics can be performed to verify the integrity of the Obstacle detection units <NUM> every time a train passes through the slide fence detection area. The system <NUM> can be designed to close the Obstacle detection unit's <NUM> protective shutters on the approach of a train. When the protective shutters close, the Obstacle detection units <NUM> can detect the closed shutters and deenergize the vital alarm relays <NUM>. If the redundant Obstacle detection unit <NUM> pairs deenergize their corresponding vital alarm relays <NUM> during train passage, the self-test can be considered successful (passed).

In one exemplary embodiment, if during train passage, one of the redundant Obstacle detection unit <NUM> pairs fails the self-test, a non-critical alert message is generated for maintenance. If the condition causing the non-critical alert message is not repaired within a predetermined period of time (e.g., five hours), the condition becomes an alarm. In another exemplary embodiment, if during train passage, both redundant Obstacle detection unit <NUM> pairs fail the self-test, an alarm is generated in the same manner as if an object is detected.

<FIG> illustrates a flow chart diagram <NUM> exemplifying control logic embodying features of a method for a slide fence system operation, in accordance with one exemplary embodiment of the present disclosure. The slide fence control logic <NUM> can be implemented as a VLC <NUM> appliance, an algorithm on a server, a machine learning module, or other suitable system. The VLC <NUM> can be a server having machine-readable instructions. The slide fence control logic <NUM> can be achieved with software, hardware, an application programming interface (API), a network connection, a network transfer protocol, HTML, DHTML, JavaScript, Dojo, Ruby, Rails, other suitable applications, or suitable combinations thereof.

The server can be implemented in hardware, software, or a suitable combination of hardware and software therefor, and may comprise one or more software systems operating on one or more servers, having one or more processors, with access to memory. Server(s) can include electronic storage, one or more processors, and/or other components. Server(s) can include communication lines, or ports to enable the exchange of information with a network and/or other computing platforms. Server(s) can also include a plurality of hardware, software, and/or firmware components operating together to provide the functionality attributed herein to server(s). For example, server(s) can be implemented by a cloud of computing platforms operating together as server(s). Additionally, the server can include memory.

Memory can comprise electronic storage that can include non-transitory storage media that electronically stores information. The electronic storage media of electronic storage may include one or both of system storage that is provided integrally (i.e., substantially non-removable) with server(s) and/or removable storage that is removably connectable to server(s) via, for example, a port (e.g., a USB port, a firewire port, etc.) or a drive (e.g., a disk drive, etc.). Electronic storage may include one or more of optically readable storage media (e.g., optical disks, etc.), magnetically readable storage media (e.g., magnetic tape, magnetic hard drive, floppy drive, etc.), electrical charge-based storage media (e.g., EEPROM, RAM, etc.), solid-state storage media (e.g., flash drive, etc.), and/or other electronically readable storage media. Electronic storage may include one or more virtual storage resources (e.g., cloud storage, a virtual private network, and/or other virtual storage resources). Electronic storage may store machine-readable instructions, software algorithms, information determined by processor(s), information received from server(s), information received from computing platform(s), and/or other information that enables server(s) to function as described herein. The electronic storage can also be accessible via a network connection.

Processor(s) may be configured to provide information processing capabilities in server(s). As such, processor(s) may include one or more of a digital processor, an analog processor, a digital circuit designed to process information, an analog circuit designed to process information, a state machine, and/or other mechanisms for electronically processing information, such as FPGAs or ASICs. The processor(s) may be a single entity or include a plurality of processing units. These processing units may be physically located within the same device, or processor(s) may represent processing functionality of a plurality of devices operating in coordination or software functionality.

The processor(s) can be configured to execute machine-readable instruction or learning modules by software, hardware, firmware, some combination of software, hardware, and/or firmware, and/or other mechanisms for configuring processing capabilities on processor(s). As used herein, the term "machine-readable instruction" may refer to any component or set of components that perform the functionality attributed to the machine-readable instruction component. This can include one or more physical processors during execution of processor readable instructions, the processor readable instructions, circuitry, hardware, storage media, or any other components.

The server can be configured with machine-readable instructions having one or more functional modules. The machine-readable instructions can be implemented on one or more servers, having one or more processors, with access to memory. The machine-readable instructions can be executed on a single networked node, or a machine cluster, which can include a distributed architecture of a plurality of networked nodes. The machine-readable instructions can include control logic for implementing various functionality, as described in more detail below. The VLC <NUM> can include machine-readable instructions implementing the control logic embodying features of a method for slide fence system operation.

The slide fence control logic <NUM> can leverage the ability of a computer platform to spawn multiple processes and threads by processing data simultaneously. The speed and efficiency of the slide fence control logic <NUM> can be greatly improved by instantiating more than one process to operate various slide fence system functionality. However, one skilled in the art of programming will appreciate that use of a single processing thread may also be utilized and is within the scope of the present disclosure.

The slide fence control logic <NUM> process flow of the present embodiment begins at step <NUM>, where the control logic can detect an object. In another exemplary embodiment the object is detected by the Obstacle detection unit <NUM> and transmits an indication of a detection, a notification of the detection (alert), or other suitable signal related to the object to the VLC <NUM>. One or more detections/indications can be received for the same object from one or more Obstacle detection units <NUM>. In another exemplary embodiment, the control logic <NUM> can detect the object in the manner disclosed above.

In another exemplary embodiment, a train approaching the detection zone <NUM> can shunt the audio frequency overlay (AFO) track circuit. In another exemplary embodiment, the de-energized overlay track circuit can activate the Obstacle detection unit <NUM> shutter control circuit or trigger the control logic <NUM> to close the protective shutters. The protective shutters can remain closed during train passage to protect the Obstacle detection unit <NUM>. When the train departs the detection zone <NUM>, the AFO track circuit can energize, thus triggering the control logic <NUM> to deactivate the LIDAR OD shutter control, opening the protector shutters.

When a qualifying object is detected, the sensing LIDAR OD Units' <NUM> alarm relays <NUM> can de-energize, indicating an alarm (detection) to the control logic <NUM>. The control logic <NUM> can, in turn, communicate the alarm to the signal system or train control system <NUM> via a network <NUM>. In another exemplary embodiment, a slide fence activation indication (alert) can also be transmitted by the control logic <NUM> to a remote location, such as a dispatcher, via the network <NUM>. In yet another exemplary embodiment, the VLC <NUM> can require a steady electrical input from all the Obstacle detection units <NUM> to keep the system at a non-alarming (permissive) state. In one exemplary embodiment, the control logic <NUM> can be programmed to interpret one LIDAR OD Unit's <NUM> de-energized state, regardless of other Obstacle detection unit <NUM> coverage area overlap, as a positive identification of an obstacle on the tracks.

In another exemplary embodiment, each LIDAR OD Unit <NUM> can be configured to identify any obstruction having a width greater than <NUM>" in its direct line of sight (<NUM>° from datum) to be an obstacle on the tracks. This ensures that a closed shutter will always generate an alarm from the LIDAR OD Unit <NUM>. Objects of proper size identified within the detection zone <NUM> can cause the Obstacle detection units <NUM> to alarm the control logic <NUM>. In another exemplary embodiment, dirt or debris that accumulates on the LIDAR OD Unit <NUM> can generate an alarm if a sufficient quantity aggregates to prevent the LIDAR OD Unit <NUM> from properly scanning its detection area. The control logic <NUM> then proceeds to step <NUM>.

At step <NUM>, the slide fence control logic <NUM> can implement a loitering time. To prevent false alarms, the slide fence control logic <NUM> can includes a loitering time feature, where an object must be detected continuously for <NUM> seconds before the object is determined a valid alarm. By implementing a loiter time, the control logic provides a window of time to prevent false hazard detections due to conditions such as an animal walking across the tracks. In one exemplary embodiment, the feature must be validating using video from a video camera. The loiter feature prevents momentary detected obstructions (e.g., birds, animals, windblown debris, etc.) from alarming the system. In another exemplary embodiment, a loitering time of <NUM> seconds or less is assumed to not add additional risk to the safety case. For example, trains can require <NUM> seconds of preview time to respond and act upon a signal indication. So, there exists a risk, with or without a loitering time, where a rock may fall and impede train traffic leading to a hazardous event. In another exemplary embodiment, in addition to preventing false alarms for operational efficiency, loitering time can be utilized as a mitigation against train crew loss of confidence in the system that can develop if false alarms are repeatedly proliferated by the system. Upon detecting an object of size, the Obstacle detection unit <NUM> can indicate an alarming condition to the VLC <NUM> by generating a message, notification or other suitable signal that is sent to VLC <NUM>. Receiving this indication from any single LIDAR OD unit can trigger the VLC <NUM> to begin a timer countdown (e.g., <NUM> seconds). Once timer countdown has expired, the VLC can communicate an alarm status to the signal system or train control system and transmit the slide fence indication to the dispatcher via the network <NUM>. The control logic <NUM> then proceeds to step <NUM>.

At step <NUM>, the slide fence control logic <NUM> determines whether an object is still in place. In one exemplary embodiment, after reopening, the Obstacle detection units <NUM> have a predetermined scan period to re-scan the area and determine a clear status. In another exemplary embodiment, for the detection zone <NUM> to be considered clear, all Obstacle detection units <NUM> must continuously report a clear state over a clear time period (e.g., at least <NUM> seconds) during the scan period (e.g., <NUM> seconds). If the object is removed and the scan period (e.g., <NUM> seconds) declares a clear status, the alarms are reset, and the control logic <NUM> proceeds to step <NUM>. If the object is not removed, the system remains in alarm and the control logic <NUM> proceeds to step <NUM>.

At step <NUM> the slide fence control logic <NUM> can activate a slide fence indication. In one exemplary embodiment, the control logic <NUM> can communicate the indication of an object to the signal system or train control system <NUM> via the network <NUM>. In one exemplary embodiment, the train control system can include a train signaling system, such that the train signaling system can be programmed to flash red to indicate to a locomotive that it must proceed at restricted speed and stop short of any obstruction. In another exemplary embodiment, the control logic can transmit the indication directly to the locomotive's onboard positive train control (PTC) system. In another exemplary embodiment, a slide fence activation indication (alert) can also be transmitted by the slide fence control logic <NUM> to a remote location, such as a dispatcher, via the network <NUM>. The control logic <NUM> then proceeds to step <NUM>.

At step <NUM> the slide fence control logic <NUM> can close to protect the Obstacle detection units <NUM>. The control logic <NUM> then proceeds to step <NUM>.

At step <NUM> the slide fence control logic <NUM> keeps the shutters closed for a protective shutter activation period, such as <NUM> seconds, or any suitable time period. The control logic <NUM> then proceeds to step <NUM>.

At step <NUM> the slide fence control logic <NUM> can reopen the shutters for a rescan cycle (e.g., <NUM> seconds). In one exemplary embodiment, after reopening, the Obstacle detection units <NUM> have a predetermined scan period to re-scan the area and determine a clear state. In another exemplary embodiment, for the detection zone <NUM> to be considered clear, all Obstacle detection units <NUM> must report a clear state for a clear time period (e.g., at least <NUM> seconds) continuously during the scan period (e.g., <NUM> seconds). The control logic <NUM> then proceeds to step <NUM>.

At step <NUM>, the slide fence control logic <NUM> determines whether the object is still in place. In one exemplary embodiment, after reopening, the Obstacle detection units <NUM> have a predetermined scan period to re-scan the area and determine a clear state. In another exemplary embodiment, for the detection zone <NUM> to be considered clear, all Obstacle detection units <NUM> must continuously report a clear state over a clear time period (e.g., at least <NUM> seconds) during the scan period (e.g., <NUM> seconds). If the object is removed and the scan period (e.g., <NUM> seconds) declares a clear state, the control logic <NUM> can reset the alarms, and the control logic <NUM> proceeds to step <NUM>. If the object is not removed, the system remains in alarm and the control logic <NUM> proceeds to step <NUM>.

At step <NUM>, the slide fence control logic <NUM> can be restored to normal operations and clear the alarm state. The control logic <NUM> then terminates or awaits a new object detection signal and can repeat the aforementioned steps.

<FIG> show a perspective view of a Wireless Slide Fence system installation <NUM>, in accordance with one exemplary embodiment of the present disclosure. Wireless Slide Fence system installation <NUM> can include train tracks <NUM>, a plurality of Obstacle detection units <NUM>, a detection zone <NUM>, an equipment shelter <NUM>, having a logic controller and power source, with access to a network. The Obstacle detection units <NUM> can be configured to scan individual zones or fields of view <NUM>, <NUM>, <NUM>, <NUM>. These individual fields of view <NUM>, <NUM>, <NUM>, <NUM> can make up the detection area <NUM>. In one exemplary embodiment, the detection area can be defined by the area at or around the track that can be monitored by at least two overlapping zones. The Obstacle detection units102 can actively scan perpendicular to the tracks <NUM> for any objects/hazards. In one exemplary embodiment, the Obstacle detection units <NUM> can scan the detection zone <NUM> for any objects between the rails and within <NUM> feet of either side of the rails, and <NUM> inches above the track. In another exemplary embodiment, the Obstacle detection units <NUM> can scan the detection zone <NUM> for any objects in any area around the train tracks within the operational limits of the Obstacle detection units <NUM>. In another exemplary embodiment, the scan dimensions are sized to the dimensions of the minimum object size that can cause a hazard or obstruct train travel along the track. If the width of the object in the horizontal plane is <NUM> inches or larger, that minimum dimension can trigger an alarm. Alternatively, the width of the object in the horizontal plane can be configured to be any width relevant to a particular application. <FIG> shows system installation <NUM> monitoring tracks <NUM> with no hazard. <FIG> shows system installation <NUM> monitoring tracks <NUM> with an object/hazard <NUM>. When an object <NUM> is in the detection area <NUM>, the obstacle detection sensor <NUM> can determine the size of the obstruction and provide an alarm output to the VLC <NUM> if the object <NUM> is determined to be a hazard based on the object characteristics, including the object's height, width, length, movement, or other suitable characteristics.

The Wireless Slide Fence system can reduce both the safety risk and operating cost of deploying maintenance personnel to facilitate side fence repairs. Advantageously, the Wireless Slide Fence does not alarm on small rocks or rocks landing clear of the track (i.e. objects posing no potential hazard or obstruction to train passage), which reduces train delays and optimizes train operations through the detection zone.

The present disclosure achieves at least the following advantages:.

Claim 1:
A wireless slide fence system (<NUM>,<NUM>) configured to detect an object capable of obstructing train passage along a track, comprising:
a plurality of wireless obstacle detection units (<NUM>),
wherein each unit is configured to scan a corresponding zone by wirelessly transmitting a signal proximate a railroad track (<NUM>) and receiving a reflection of the signal from an object proximate the railroad track (<NUM>),
wherein one or more of the plurality of obstacle detection units (<NUM>) are further configured to detect an object in the zone (<NUM>) and generate a detection alert, when the reflected signal is received; and
a vital logic controller (<NUM>) operably coupled to the obstacle detection units (<NUM>) and configured to control the obstacle detection units (<NUM>), receive the detection alert, and transmit an indication of an obstacle to a train control system (<NUM>) to reduce the speed of or stop a train (<NUM>);
wherein the obstacle detection units (<NUM>) include shutters configured to open and close to protect the obstacle detection unit (<NUM>) from damage,
wherein the shutters are configured to close after an object has been detected for a protective shutter activation period, and to reopen for a predetermined scan period to rescan the zone (<NUM>) for the object;
wherein the vital logic controller (<NUM>) is configured to clear the detection alert and the indication of the obstacle to the train control system (<NUM>) via an encrypted network (<NUM>) if during the rescan, all detection units of the plurality of detection units (<NUM>) continuously report that the object is removed from the zone over a clear time period during the predetermined scan period.