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How to Make Railroad Level Crossings Safer and Smarter

Modern level crossings (or railroad crossings in American terminology) have come a long way from the early days of human railway employees waving red flags and shining lanterns to clear railroad tracks of vehicles and pedestrian traffic for oncoming trains. As is still the case today, nineteenth century railways were deeply concerned with preventing accidents and protecting assets. Responding to these concerns, railroads began to implement manual, and eventually electrical, boom gates (crossing barriers) to block road traffic from the rail tracks. Although clear, simple signage may be sufficient for level crossings in sparsely inhabited regions, high traffic intersections today often feature active warning systems, which include electrical boom gates, flashing lights, and warning bells that are triggered when an approaching train trips a nearby track circuit.

Despite these modern safeguards, railroad crossings continue to pose a serious safety issue around the world. In fact, level crossing accidents claim the lives of roughly 300 Americans and 400 Europeans every year. Besides the tragic loss of human life, railroad crossing accidents cause expensive asset damage (e.g., train cars, rail tracks, level crossing equipment, etc.), time-consuming traffic jams, and inconvenient service suspensions. More so than other railway failures, such as those related to turnouts (railroad switches), railroad crossing accidents tend to be attributed to human error and violations of traffic regulations. Although human error may seem like an ineliminable obstacle, it is one cause of accidents that can be reduced by equipping people with the right information at the right time. As a result, many countries have been investigating "smarter" ways to improve existing railroad crossing warning systems by implementing advanced communication and control technologies to prevent accidents.

How to Build a Smarter Level Crossing

Transportation professionals need to have all relevant data to conduct thorough risk evaluations before proceeding with expensive and space-intensive grade separation projects. More specifically, an effective "smart" level crossing will need to be designed to provide data accuracy for accident prevention as well as data completeness for accident analysis in the event of a collision.

Data Accuracy for Accident Prevention

Active warning systems for level crossings have traditionally been train-oriented and geared more towards protecting railway assets than helping vehicles and pedestrians make better split-second decisions. Although protecting and monitoring the condition of railway assets remain crucial objectives in ensuring journey reliability and preventing derailments, smart level crossings go even further by providing more accurate, real-time information to pedestrians, vehicles, train drivers, and even a faraway OCC (operation control center). The following improvements are three important ways improved data accuracy can make level crossings smarter and prevent accidents.

Advanced Obstacle Detection

Exposed to the elements, the clearance zone of a level crossing is shared by trains, vehicles, pedestrians, and even wildlife and wind-blown debris. Although we always want to avoid collisions between a train and a stranded vehicle 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 level crossing systems are now adopting the latest in CCTV surveillance and image processing 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 wayside cabinet to process high quality images streamed from rugged IP video cameras—are used to help railway operators determine if a real obstacle exists by checking the detected object's entry and dwell time in the clearance zone.

Real-Time Equipment Status

Smart railroad crossings also need to keep track of vital parameters and constantly changing conditions for many different kinds of assets. Increasingly sophisticated data acquisition systems—comprised of the latest RTU (remote terminal unit) controllers—are now used to provide around-the-clock monitoring for wayside equipment, operating statistics, and environmental conditions. Tucked inside a space-saving wayside cabinet, compact RTU controllers can connect all the myriad I/O, Ethernet, and serial interface sensors at a level crossing to an integrated 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.

Variable Message Warning Signs

Besides providing real-time data to warn railway operators and train drivers about potential obstacles on the tracks and malfunctioning equipment, smart level crossings are also deploying LED variable message signs to display important information 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 should also provide real-time status updates about an approaching train to help drivers and pedestrians answer the following questions:

  • How much time before the train reaches the level 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 level crossings should also provide more historical information to railway operators, law enforcement agencies, and regional transportation authorities for accident analysis and future prevention. This means that vital data about the condition and operation of all the data acquisition and monitoring subsystems comprising the level crossing need to be recorded and logged even before an accident takes place so that investigators can go back and examine all the factors contributing to the crash.

Around-the-Clock Asset Monitoring

In order to determine whether an accident was caused by mechanical failure, smart level crossings deploy advanced data acquisition systems to continuously monitor the condition of vital assets and warning system components. In particular, investigators 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 cameras designed for harsh, outdoor environments are used in smart level crossings to provide 24/7 video surveillance for the clearance zone. In addition, high quality state-of-the-art network video recorders are also installed in the wayside cabinet to store video streamed from the cameras so that accident investigators can replay the events leading up to a collision and identify its cause.

Anatomy of a Smart Level Crossing

The following diagram illustrates how remote terminal units, rugged IP video cameras, and industrial network video recorders can be used create a smarter and safer level crossing that provides both real-time and historical data for accident prevention and root cause analysis.

Smarter Data Acquisition

In the smart level crossing system above, Moxa's ioPAC 8500 modular RTU controller is used to monitor the status of all the active warning devices, including the warning lights and bells, electrical boom gates, laser sensors, and nearby track circuits. Besides its compact size (which is ideal for wayside cabinets with limited space), the ioPAC 8500 RTU controller's modular design supports a versatile collection of I/O modules—including digital inputs, digital outputs, analog inputs, resistance temperature detectors, thermocouples, HSPA, and serial modules—to connect all the different interface precision instruments and sensors used to monitor the active warning system. Tailor-made for railway applications, the following features illustrate some of the unique benefits the ioPAC 8500 RTU controller offers level crossings.

Smarter Surveillance

Besides taking advantage of RTU controllers tailor-made for wayside applications, the smart level crossing above also uses Moxa's VPort 36-1MP rugged IP cameras to capture and encode real-time video of the clearance zone, which is then streamed to an MxNVR-IA8 industrial network video recorder inside the wayside cabinet. Although the principal image processing technology that makes the above solution so "smart" is Moxa's IVA software application, the CCTV cameras and network video recorders deployed also need to be ruggedly designed with industry certified reliability.


Although active warning systems featuring barrier gates, flashing lights, and warning bells are a fairly common site at high traffic level crossings around the world, these at-grade intersections continue to present real dangers to both rail and road traffic. At the same time, it may not always be practical or necessary to remove a railroad crossing through costly grade separation in order to improve safety for rail and road travelers. As illustrated in the smart level crossing example discussed above, the latest advancements in data acquisition and IP video surveillance can equip active warning systems with both real-time and historical information to make level crossings smarter and safer.

In other words, smarter data acquisition and IP video surveillance technologies are keys to building an effective intelligent level crossing. More specifically, advanced remote terminal units, such as the ioPAC 8500, can provide millisecond-level time stamps, kHz-level analog input sampling rates, and analog input prerecording to improve data accuracy and completeness, in addition to connecting all the active warning devices to an integrated wayside monitoring system. Furthermore, industrial-grade IP video cameras and network video recorders, such as the VPort 36-1MP and MxNVR-IA8, offer rugged design, industry certified reliability, and intelligent video analysis capabilities for smarter surveillance. By providing railway operators, automobile drivers, and pedestrians with the right information at the right time, needless train-and-car collisions can be avoided. Consequently, global efforts to reduce highly preventable accidents at railroad crossings are moving towards developing "smart" level crossings that provide both real-time and historical data about railway assets and wayside equipment for accident prevention and root cause analysis.

To learn more about how to make level crossings safer and smarter, download the complete white paper here.

For more information about RTU controllers, visit here.

For more information about rugged IP video surveillance solutions, visit here.

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