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Fast Track Integration for Wayside Condition Monitoring and Preventive Maintenance

The high financial and reputational costs of railway accidents and long delays have led railway infrastructure managers to adopt increasingly sophisticated preventive maintenance procedures. However, the ability of railway operators and maintenance engineers to prevent costly system failures and optimize resource allocation depends on myriad wayside condition statuses provided by separate monitoring systems. These data acquisition systems are often comprised of many sensors, transducers, and remote terminal units running on different platforms and closed communication protocols, which can make maintenance more challenging and costly.

To ensure journey reliability and reduce expenditures, infrastructure managers and system integrators for railways should use a single, integrated condition monitoring platform that provides railway operators with ready access to all relevant statuses for predictive maintenance and asset management.

  • Using one platform for all condition monitoring subsystems
  • Wayside condition monitoring example

Using One Platform for All Condition Monitoring Subsystems

Integrating a wayside condition monitoring system for railway preventive maintenance can be a herculean challenge. Although system integrators still need to combine myriad condition monitoring subsystems to help infrastructure managers reduce maintenance costs and ensure journey reliability, using one hardware and software platform can alleviate much of the headache. More specifically, reproducing a single platform with the following characteristics for each condition monitoring subsystem can make it easier to manage multiple asset types, deploy and maintain wayside monitoring equipment, and develop HMI software for SCADA and data analysis.

  • Modular hardware design enables system integrators to connect different interface inputs and outputs to a single remote terminal unit (RTU) for front-end data downsizing and easy deployment. Besides the convenience and efficiency of supporting multiple asset types with just one piece of equipment, some hardware vendors also provide a compact design to save even more space at wayside locations.
  • Hot-swappable I/O modules provide plug-and-play simplicity for easy maintenance. Particularly, the ability to replace component modules without shutting down the system saves time for maintenance engineers. Moreover, modules that do not need to be replaced or serviced can stay online during maintenance visits, improving overall system availability.
  • Open standards and programming languages, such as C/C++ and IEC 61131-3, allow system integrators to design their own programs and provide more add-on value. Although propriety software and protocols may be sufficient for specific components in isolation, these closed platforms ultimately make it more difficult for system integrators to develop new programs tailored to end-user needs and manipulate data to support increasingly sophisticated analysis software and risk-based inspection tools. In contrast, both C/C++ and IEC 61131-3 are open standards that are commonly used for RTUs and offer unrestricted access for system integrators to develop software for front-end data downsizing and back-end data analysis.

In summary, modular RTU controllers with hot-swappable I/O modules can connect different interface inputs and outputs to support multiple asset types, and some even come with API libraries and software tools—such as an open standard OPC server and database gateway—for easy integration with the back-end SCADA system or data analysis software. Although one size does not fit all, using a modular, hot-swappable hardware design with an open software platform as a template for each wayside monitoring subsystem can be a time-saving and cost-effective alternative to rigid proprietary systems.

Figure 1: Integrated Wayside Condition Monitoring Platform

Each remote monitoring subsystem (e.g., turnouts, track temperature, railroad crossings, etc.) can be integrated by connecting different interface sensors at each field site to a modular RTU controller (inside a DAB) that supports different I/O types and communication interfaces, and also provides easy data integration software based on open standards (e.g., OPC server and database gateway) to mitigate hardware and software interoperability issues.

Wayside Condition Monitoring Example

According to a recent high-level performance and cost study conducted by the International Union of Railways, turnout monitoring systems have the lowest reliability and availability—but the highest maintenance costs—among all the critical monitoring subsystems used in railway preventive maintenance.[5] Thus, the following discussion will use turnout condition monitoring to illustrate the potential benefits of deploying a single, integrated monitoring platform from a hardware vendor that provides easy data integration software tools.

One of the most vital components of all railway infrastructures, railroad turnouts are basically mechanical installations that guide moving trains from one track to another. Also called a railroad switch in North American terminology, a turnout is comprised of a set of points (two linked tapered rails, also called switch blades in North America) inside the diverging stock rails (i.e., the outer rails). The fact that turnouts have movable parts and a motor to move the points to the desired position while accommodating tight curves, lateral forces, and impact loads at transitions, necessitates a highly demanding maintenance schedule.

Figure 2: Integrated Turnout Condition Monitoring Topology

Railway operators rely on monitoring information from many different conditions and remote subsystems that can be integrated into a single Ethernet backbone or cellular network for centralized control.

When used in turnout condition monitoring applications, a modular RTU controller can connect an array of digital and analog sensors—such as motor current sensors, force sensors, and open/close sensors at a turnout—and record real-time measurements. Although precision instruments used to measure each parameter still need to come from highly specialized manufacturers, system integrators can mitigate interoperability issues by connecting all the sensors at each monitoring site to a single hardware and software platform. For example, Ethernet switches running on the same platform can be deployed to connect the RTU controllers to an Ethernet backbone for the entire railway, continuously transmitting critical asset information to a remote control center for centralized monitoring and analysis. For network redundancy or locations where laying physical wires is impractical, cellular controllers from the same vendor can also be deployed to transmit monitoring data wirelessly from the RTU controller to the operation control center.

Although currently available railway monitoring solutions cannot be used out of the box for advanced risk-based maintenance, system integrators can still save valuable deployment time, effort, and costs by taking advantage of hardware components (e.g., modular RTU controllers and Ethernet switches) and easy data integration tools (e.g., OPC servers and database gateways) from the same vendor. By converting raw data from myriad sensors into a more manageable form for SCADA and data analysis software, using a single, open platform can even provide a flexible foundation for integrating next-generation data analysis software in the future. Even though the aforementioned turnout example focused on just one wayside monitoring subsystem, the integrated approach advocated still applies to all the other subsystems that support the overarching railway wayside condition monitoring system. Thus, deploying an integrated monitoring platform, like the solution above, at each field site not only reduces excess equipment that need to be maintained, but also improves system-wide responsiveness through the elimination of unnecessary service visits and the provision of readily available asset information.

Conclusion

Recognizing the benefits of increasingly robust condition-based maintenance, infrastructure managers are willing to invest in remote monitoring and data acquisition technologies to provide maintenance engineers and railway operators with readily available asset information to predict and preempt future failures. At the same time, exorbitant track maintenance and renewal costs are also putting pressure on infrastructure managers to eliminate unnecessary expenditures, improve efficiency, and optimize resource allocation. Accordingly, system integrators employed or contracted by infrastructure managers and railway operators will need to keep these performance and budgetary concerns in mind when integrating condition monitoring systems for railway preventive maintenance.

Yet the system integrator’s task is far from easy. Traditional wayside condition monitoring systems for railway preventive maintenance often piece together hardware and software from different platforms that may succumb to interoperability issues and make maintenance more difficult. Moreover, system integrators need to figure out how to manage multiple asset types, deploy and maintain a highly complex and distributed system, and develop programs that deliver add-on value. Instead of using multiple hardware platforms and proprietary software solutions for different wayside monitoring subsystems, system integrators should use a single, open platform that supports multiple interfaces and provides easy data integration software. In particular, using a modular, hot-swappable hardware design with an open software platform as a template for individual wayside monitoring subsystems can save time and deployment costs compared to rigid proprietary systems. More importantly, such platforms will not only simplify the arduous task of integration, but also help infrastructure managers reduce maintenance costs without sacrificing track performance.

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