1. Project Background & Need
South Korea’s mountainous terrain means its railway network often traverses hills and gorges. During the summer flood season, the country is susceptible to torrential rains from monsoons and typhoons, which can trigger sudden flash floods, debris flows, and slope landslides in mountainous areas, posing a severe threat to railway operational safety. Traditional tipping-bucket rain gauges require regular maintenance, are prone to clogging, and may suffer from mechanical lag and counting errors during extreme downpours, making them inadequate for the need for real-time, high-precision, low-maintenance rainfall monitoring.
To ensure operational safety, South Korea’s infrastructure management authorities urgently needed to deploy an advanced and reliable automatic rainfall monitoring network along critical mountainous railway sections. The required equipment had to withstand harsh environments, operate with minimal maintenance, and provide real-time, accurate data on rainfall intensity and accumulation to deliver timely alerts to the train dispatch system.
2. Solution: Optical Rain Gauge Monitoring System
The project selected the Optical Rain Gauge (or Optical Rain Sensor) as the core monitoring device to build a distributed rainfall monitoring and early warning system.
- Working Principle:
The optical rain gauge operates on the principle of infrared optical scattering. The sensor emits a beam of infrared light at a specific wavelength through a measurement area. When there is no rain, the light passes through directly. When raindrops fall through the measurement area, they scatter the infrared light. The intensity of the scattered light detected by the receiver is proportional to the size and number of raindrops (i.e., the rainfall intensity). By analyzing the signal variation with built-in algorithms, the sensor calculates the instantaneous rainfall intensity (mm/h) and accumulated rainfall (mm) in real-time. - System Deployment:
Optical rain gauges were installed at key points along railway lines in high-risk geological hazard zones (e.g., on slopes, near bridges, at tunnel entrances). The devices were mounted on posts, with the sensor lens angled towards the sky to ensure an optimal measurement area.
3. Application Implementation
- Real-time Data Collection: The optical rain gauges operate 24/7, taking multiple samples per second to detect the start, end, intensity, and trends of rainfall in real-time.
- Data Transmission: The collected rainfall data is transmitted in near real-time (at minute-level intervals) to a central data platform at the regional monitoring center via built-in 4G/5G wireless communication modules.
- Data Analysis & Early Warning:
- The central platform integrates data from all monitoring points and sets multi-level rainfall threshold alarms.
- When the rainfall intensity or accumulated rainfall at any point exceeds pre-set safety thresholds, the system automatically triggers an alarm.
- Alarm information (including specific location, real-time rainfall data, and exceedance level) is immediately pushed to the dispatcher’s interface at the Railway Traffic Control Center (CTC).
- Linked Control: Based on the warning level, dispatchers quickly initiate emergency protocols, such as issuing speed restrictions or emergency suspension orders for trains approaching the affected section, thereby preventing disasters and ensuring passenger safety.
4. Embodied Technical Advantages
- No Moving Parts, Maintenance-Free: The lack of mechanical components eliminates issues like clogging, necessary regular cleaning, and mechanical wear associated with traditional tipping-bucket gauges. This makes them ideal for long-term, unattended operation in remote and harsh mountainous environments.
- Fast Response & High Accuracy: The optical measurement method offers an extremely fast response time (up to seconds), accurately capturing instantaneous changes in rainfall intensity and providing critical time for warnings.
- Strong Resistance to Interference: An optimized optical design effectively minimizes interference from environmental factors like dust, fog, and insects, ensuring data reliability.
- Low Power Consumption & Easy Installation: The devices have low power requirements, often supported by solar panels, and are simple to install without significant civil engineering work.
5. Project Outcomes
The implementation of this system elevated South Korea’s railway disaster prevention capabilities from “passive response” to “active warning.” The precise, real-time data from the optical rain gauges enabled the dispatch department to:
- Make more scientific safety decisions, reducing economic losses associated with excessive preventive shutdowns.
- Significantly enhance railway transportation safety and punctuality.
- The accumulated long-term rainfall data also provides valuable support for geological risk assessment and infrastructure planning along railway corridors.
This case demonstrates the successful application of optical rain gauges in the field of critical infrastructure safety, providing an excellent model for solving rainfall monitoring challenges in complex environments.
Complete set of servers and software wireless module, supports RS485 GPRS /4g/WIFI/LORA/LORAWAN
For more rain gauge sensor information,
please contact Honde Technology Co., LTD.
Email: info@hondetech.com
Company website: www.hondetechco.com
Tel: +86-15210548582
Post time: Sep-11-2025