Page 48 - Occupational Health & Safety, March 2017

TRANSPORTATION SAFETY
journey reliability and preventing derail- ments, smart railroad crossings go even further by providing more accurate, real- time information to pedestrians, vehicles, train drivers, and even a faraway operation control center (OCC).
The following improvements are three important ways improved data accuracy can make railroad crossings smarter and prevent accidents.
1. Advanced Obstacle Detection. Exposed to the elements, the clearance zone of a crossing is shared by trains, vehicles, pedes- trians, and even wildlife and wind-blown debris. Although we always want to avoid collisions between a train and a stranded ve- hicle or pedestrian, it may not be necessary to stop a speeding locomotive each time an agile deer leaps across the tracks. As a result, smart crossing systems are now adopting the latest in CCTV surveillance and image pro- cessing technology to visually inspect boom gate conditions, identify trapped objects, and monitor the movements of the object in real time. In particular, industrial-grade network video recorders—installed inside a way- side cabinet to process high-quality images streamed from rugged IP video cameras— are used to help railway operators determine whether a real obstacle exists by checking the detected object’s entry and dwell time in the clearance zone.
2. Real-Time Equipment Status. Smart railroad crossings also need to keep track of vital parameters and constantly chang- ing conditions for many different kinds of assets. Increasingly sophisticated data ac- quisition systems—comprised of the latest RTU (remote terminal unit) controllers— are now used to provide around-the-clock monitoring for wayside equipment, oper- ating statistics, and environmental condi- tions. Tucked inside a space-saving wayside cabinet, compact RTU controllers can con- nect all of the myriad I/O, Ethernet, and se- rial interface sensors at a crossing to an in- tegrated wayside monitoring system. More specifically, by sending error messages about potentially malfunctioning barriers, motors, lights, and alarms from a far-flung railroad crossing to the OCC, advanced RTU controllers enable railway operators to instruct a speeding train to slow down or stop well before it reaches an intersection.
3. Variable Message Warning Signs. Besides providing real-time data to warn railway operators and train drivers about potential obstacles on the tracks and mal-
functioning equipment, smart railroad crossings are also deploying LED variable message signs to display important infor- mation about approaching trains so vehicle drivers and pedestrians can make better decisions on the spot. For example, if an impatient driver knows that a speeding train will arrive at the intersection in less than 3 seconds, he or she may think twice before trying to “run” the crossing. As a result, “smart” warning signs also should provide real-time status updates about an approaching train to help drivers and pe- destrians answer the following questions:
■ How much time before the train reaches the crossing?
■ Which direction is the train coming from?
■ What is the speed of the train? ■ How far away is the train?
Data Completeness
for Accident Analysis
In the unfortunate event of an accident, smart railroad crossings also should pro- vide more historical information to railway operators, law enforcement agencies, and regional transportation authorities for ac- cident analysis and future prevention. This means that vital data about the condition and operation of all the data acquisition and monitoring subsystems comprising the crossing need to be recorded and logged even before an accident takes place so that investigators can go back and examine all factors contributing to the crash.
Around-the-Clock Asset Monitoring
In order to determine whether an accident was caused by mechanical failure, smart railroad crossings deploy advanced data ac- quisition systems to continuously monitor the condition of vital assets and warning system components. In particular, investi- gators will need this information to answer the following questions and determine the cause of the accident.
■ How long did it take for the boom gate to drop after the strike-in time?
■ Were the warning lights and alarms working properly?
■ How fast was the train going?
■ Did environmental conditions (e.g., operating temperature, wind speed, wind direction) play a role in the accident?
Non-Stop Network Video Recording
Besides high-quality image processing for
obstacle detection, advanced CCTV cam- eras designed for harsh, outdoor environ- ments are used in smart railroad crossings to provide 24/7 video surveillance for the clearance zone. In addition, high-quality state-of-the-art network video recorders are installed in the wayside cabinet to store vid- eo streamed from the cameras so that acci- dent investigators can replay the events lead- ing up to a collision and identify its cause.
Anatomy of a Smart Crossing
Although many high-traffic railroad cross- ings in developed countries are already equipped with active warning systems such as electrical boom gates, flashing lights, and warning bells, smart railroad crossings bring together the latest communication and sur- veillance technologies for data acquisition and image processing to make these intersec- tions even safer. This section will discuss spe- cific ways remote terminal units, rugged IP video cameras, and industrial network video recorders can be used to create a smarter and safer crossing that provides both real-time and historical data for accident prevention and root cause analysis.
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Smarter Data Acquisition
In the smart crossing system above, a mod- ular RTU controller is used to monitor the status of all active warning devices, includ- ing the warning lights and bells, electrical boom gates, laser sensors, and nearby track circuits. The RTU controller’s modular de- sign supports a versatile collection of I/O modules—including digital inputs, digital outputs, analog inputs, resistance tempera- ture detectors, thermocouples, HSPA, and serial modules—to connect all of the dif- ferent interface precision instruments and sensors used to monitor the active warning system. Here are other features to look for in an RTU for this type of application:
1. Millisecond-Timestamps for More Ac- curate Data Analysis. First, an approaching train usually trips the track circuit about
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