A redundant railway unmanned crossing alarm system
By employing redundant design and signal processing technology, and combining passive and active magnets, the problem of missed detection in traditional railway unmanned crossing alarm systems under low speed and extreme conditions has been solved. This achieves highly accurate train detection, adapts to a wide range of train speeds, and prevents traffic accidents.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANXI TAIGANG STAINLESS STEEL CO LTD
- Filing Date
- 2025-06-18
- Publication Date
- 2026-06-23
AI Technical Summary
Traditional railway unmanned crossing alarm systems are prone to missing detections under low-speed operation, low-magnetic vehicle bodies, or extreme weather conditions, and cannot meet the missed alarm rate requirements of railway safety regulations.
The design employs redundancy, combining passive and active magnets. By adding an adapter board within the controller, it can connect to both passive and active magnets. The active magnet outputs a positive pulse voltage signal under low-speed or extreme conditions. Combined with a filter capacitor and a freewheeling diode to process the signal, it ensures accurate alarm triggering.
It achieves a reduction in the false alarm rate to below 0.005% within a vehicle speed range of 0.1-200km/h, improving the accuracy of the alarm system, adapting to various operating conditions, and preventing traffic accidents.
Smart Images
Figure CN224392624U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of railway safety monitoring technology, and in particular relates to a redundant railway unmanned crossing alarm system. Background Technology
[0002] Some railway crossings with low pedestrian traffic are unmanned. Alarm systems are used to alert pedestrians of an impending train, preventing accidents. Traditional unmanned railway crossing alarm systems rely on passive magnets, which generate an induced current by the train's wheel axle cutting through the magnetic field to trigger the alarm. However, in low-speed operation, with low-magnetic train bodies (such as light rail), or in extreme weather conditions (such as snow cover), passive magnet alarm systems are prone to missed detections. A single sensor cannot cover all possible scenarios, and in practical applications, the missed alarm rate is still higher than the standard stipulated by railway safety regulations (<0.01%). Utility Model Content
[0003] The purpose of this invention is to provide a redundant railway unmanned crossing alarm system to solve the problem that traditional alarm systems are prone to missed detection under low-speed operation, low-magnetic car bodies, or extreme weather conditions.
[0004] To achieve the above objectives, the present invention adopts the following technical solution:
[0005] A redundant alarm system for unmanned railway crossings includes passive magnets and active magnets. Active magnets are installed on both sides of the unmanned crossing, and passive magnets are installed outside the active magnets. Both active and passive magnets are connected to a controller, which is connected to an alarm sounder. The controller's main board includes two circuits: a passive magnet control circuit and an active magnet control circuit. The passive magnet control circuit includes a passive magnet input J1 and a current-limiting resistor R1. The passive magnet input J1 is connected to the current-limiting resistor R1, which is connected to an isolation optocoupler U1. The isolation optocoupler U1 is connected to the alarm sounder. An adapter board is added to the main board of the controller to match the interface; the active magnet control circuit is connected to the adapter board.
[0006] Preferably, the active magnet control circuit includes an active magnet input J1 and a freewheeling diode D1. The active magnet input J1 is connected to the adapter board. The active magnet input J1 is connected to a current-limiting resistor R1 and a filter capacitor C1 in parallel. The filter capacitor C1 is connected in parallel with the freewheeling diode D1. The freewheeling diode D1 is connected to the active magnet output J2. The active magnet output J2 is connected to an alarm sounder.
[0007] When a vehicle approaches, the electrical signal of the passive magnet fluctuates greatly. In order to ensure that the signal can be detected even at low speeds, the current limiting resistor R1 is often chosen to be relatively small. If an active magnet is directly connected, the isolation optocoupler will be burned out due to excessive current. Therefore, when connecting an active magnet, an adapter board must be added to the input end to match the interface.
[0008] Because active and passive magnets output different electrical signals, the interface between the control board and the magnets is not interchangeable; it can only connect to either active or passive magnets. To meet the needs of field use, an adapter board is required so that the control board can connect to both active and passive magnets. Passive magnets output a 0-14V AC signal; the faster the train travels, the stronger the signal. At low speeds, the signal is weak and cannot be detected. Active magnets output a 24V DC signal, and the signal strength is independent of train speed.
[0009] Working principle: When the train wheelsets approach at normal speed, the passive magnet generates an electrical signal that activates the input of the isolation optocoupler, causing the output of the isolation optocoupler to conduct, generating current to trigger the alarm sound to detect the approaching train.
[0010] When the train is moving slowly, or in low-magnetic-field conditions (such as light rail), or under extreme weather conditions (such as snow cover), the active magnet detects changes in the magnetic field and outputs a positive pulse voltage signal of 24V. This generates current to trigger an alarm sound, indicating an approaching vehicle. The active magnet outputs a DC signal, so the polarity must be carefully considered during wiring. When the train's wheels leave the sensing range of the active magnet, the output voltage signal drops to 0V. A filter capacitor C1 reduces interference from some high-frequency signals, and a freewheeling diode D1 accelerates the signal reduction after the wheel leaves. This sensing technology can accurately monitor vehicles within a distance of 0 to 20 millimeters and at speeds as low as 0.02 km / h. The output signal of the active magnet is unaffected by train speed, railway electrification fields, or lightning strikes. Therefore, the active magnet can provide more accurate physical positioning information for the wheels.
[0011] The beneficial effects achieved by this utility model are as follows:
[0012] (1) The control board of the controller can be connected to both active magnet input and passive magnet input through the connection board. The electrical signal output by the active magnet is a 24V DC signal. The strength of the electrical signal is independent of the vehicle speed. The electrical signal will not be poor due to the vehicle speed being too low, thus preventing missed detection.
[0013] (2) In the active magnet control circuit, the filter capacitor C1 reduces some high-frequency signal interference, and the freewheeling diode D1 accelerates the reduction of electrical signal after the wheel leaves, preventing false alarms and improving the accuracy of the alarm system.
[0014] (3) By using both active and passive magnets to detect trains, the alarm system will not miss any trains, whether the train is running at high speed, low speed, or with a low magnetic body (such as light rail) or under extreme weather conditions (such as snow cover). The range of train speeds it can adapt to is expanded, thus preventing traffic accidents. Attached Figure Description
[0015] Figure 1 This is a schematic diagram of the structure in an embodiment of the present utility model;
[0016] Figure 2 This is a circuit diagram of the passive magnet control circuit in an embodiment of this utility model;
[0017] Figure 3 This is a circuit diagram of the active magnet control circuit in an embodiment of this utility model.
[0018] Explanation of the attached diagram labels: 1. Passive magnet; 2. Active magnet; 3. Unmanned passageway; 4. Controller; 5. Alarm sounder. Detailed Implementation
[0019] The technical solution of this utility model will be described in detail below with reference to the accompanying drawings and embodiments.
[0020] like Figure 1-3 As shown, a redundant railway unmanned crossing alarm system includes a passive magnet 1 and an active magnet 2. Active magnets 2 are installed on both sides of the unmanned crossing 3, and passive magnets 1 are installed on the outer sides of the active magnets 2. Both active magnets 2 and passive magnets 1 are connected to a controller 4, which is connected to an alarm sounder 5. The main control board inside the controller 4 includes two circuits: a passive magnet control circuit and an active magnet control circuit. The passive magnet control circuit includes a passive magnet input J1 and a current-limiting resistor R1. The passive magnet input J1 is connected to the current-limiting resistor R1, which is connected to an isolation optocoupler U1. The isolation optocoupler U1 is connected to the alarm sounder 5. An adapter board on the main control board inside the controller 4 is used for interface matching; the adapter board is connected to the active magnet control circuit. The active magnet control circuit includes an active magnet input J1 and a freewheeling diode D1. The active magnet input J1 is connected to a current-limiting resistor R1 and a parallel filter capacitor C1. The filter capacitor C1 is connected in parallel with the freewheeling diode D1. The freewheeling diode D1 is connected to the active magnet output J2, and the active magnet output J2 is connected to the alarm sounder 5. Through an adapter board, the control main board can be connected to both active and passive magnet inputs. At normal train speeds, the passive magnet is used, and the alarm is triggered by the induced current generated by the train wheel axle cutting the magnetic field. At low train speeds, in low-magnetic vehicle bodies (such as light rail), or in extreme weather conditions (such as snow cover), the active magnet is used to output a positive pulse voltage signal to trigger the alarm, providing dual early warning to prevent missed detection and avoid traffic accidents.
[0021] Through experimental simulation tests, the false alarm rate was reduced to below 0.005%, and the applicable vehicle speed range was expanded to 0.1-200km / h.
Claims
1. A redundant railway unmanned level crossing warning system, characterized in that, The system includes both passive and active magnets. Active magnets are installed on both sides of the unmanned pedestrian crossing, and passive magnets are installed on the outside of the active magnets. Both active and passive magnets are connected to a controller, which is connected to an alarm sounder. The main control board of the controller includes two circuits: a passive magnet control circuit and an active magnet control circuit. The passive magnet control circuit includes a passive magnet input J1 and a current-limiting resistor R1. The passive magnet input J1 is connected to the current-limiting resistor R1, which is connected to an isolation optocoupler U1. The isolation optocoupler U1 is connected to the alarm sounder. An adapter board is added to the main control board of the controller to match the interface. The active magnet control circuit is connected to the adapter board.
2. A redundant railway unmanned level crossing warning system according to claim 1, characterized in that, The active magnet control circuit includes an active magnet input J1 and a freewheeling diode D1. The active magnet input J1 is connected to the adapter board. The active magnet input J1 is connected to a current-limiting resistor R1 and a filter capacitor C1 in parallel. The filter capacitor C1 is connected in parallel with the freewheeling diode D1. The freewheeling diode D1 is connected to the active magnet output J2. The active magnet output J2 is connected to an alarm sounder.