Wind Monitoring System
A MISSION ORIENTED SOLUTION FOR SAFE RAILWAY TRAVEL


LAR (Lantau Airport Railway)
The Lantau Airport Railway (LAR) operated by the Mass Transit Railway Corporation (MTRC) provides high speed transportation between the Hong Kong International airport (Chek Lap Kok) and various locations in the city. 
 

3D model stimulating derailment under strong wind  
Background
The MTRC has long achieved high performance in safety and quality service for its urban lines. However, the LAR is different from the urban lines in various aspects:- It operates at a much higher speed (~135km/hour)- The risk of train derailment and overturning is greater than on the urban lines because the rail is exposed and the terrain on Lantau Island creates complex weather patterns.

In order to assess the risk of operating a high speed train in an exposed area like the Lantau Island, the MTRC has appointed the British Rail Research Group to conduct a study about this situation. Findings had indicated that side winds on railway vehicles produce forces and moments which can overturn or cause derailment of the train from the track. 

Overview
   

The Wind Monitoring System (WMS) is a strong wind warning system for the LAR. This is a real-time distributed system with meterological sensors installed at strategic locations along the track to collect real-time meteorological profile data for the decision support system. The profile data are processed by the system, which performs multivariate analysis to assess the impact of the wind characteristics. The results are then consolidated into very precise information by classifying the impact into various warning levels:

This warning system facilitates real-time decision support for the operation staff in the control room of the MTRC to decide if to continue, scale down or terminate operations during strong wind and or typhoon episodes.
Technology
 
Wind anemometers are used to determine wind speed and wind directions along the LAR

The natural topography and the terrain on Lantau Island cause strong wind along the railway track to be amplified by wind gaps. The wind may reach intensities that may hamper the normal operation of the airport train service. Meteorological sensors are installed at strategic locations for on-site measurements and small-scale numerical flow field modeling.

The system is designed for maximum reliability and minimum down-time. It is a robust system with redundant hardware and control processes that automatically handle defective sensors and/or data communication without interrupting the real-time data collection. Under very extremeconditions when sensors are not in operation, the system has the intelligence to estimate the wind condition by regression using historical data and data from the nearby sites.

Field Program
Sensor Installation

A field program was essential for obtaining wind profilesfrom strategic locations along the LAR. We installed a number of anemometers to collect wind data that were transmitted to the data center in HKUST for processing, analysis and archiving.

Availability

The WMS achieves an availability of better than 99.99% where availability is defined as the Device being operational with all components fully serviceable to their designed specification.