Independent safety assessor TÜV SÜD has certified Piper Networks with a ENELEC Safety Integrity Level 4 (SIL-4) Certification for its Ultra Wideband (UWB) train control system.
The certification is a milestone achievement for Piper and the transportation industry as it becomes the first ever UWB-based position and speed technology to achieve vitality, according to the company.
The system is now ready for integration with signaling and train control programs being implemented by transportation agencies and their engineering contractors in the U.S. and worldwide. Most recently, Piper’s UWB positioning system has been piloted on the New York Metropolitan Transportation Agency’s (MTA) subway system on the 7 Line in Flushing, New York.
How does the UWB train control system work?
Using a time-of-flight measurement of radio transmissions, Piper determines the precise location of moving trains and calculates their speed. In a vital system, safety is the paramount concern for train control requirements and Piper’s UWB system provides end-to-end verification and validation of all system components and processes.
Now that it is SIL-4 certified, the Piper system can be more seamlessly integrated with higher level systems to ensure that they are operating with the highest levels of confidence.
What is Safety Certification?
The standard used for this is CENELEC, a European standard that the U.S. also adopts. CENELEC is broken down into different levels of risk analyses, called SIL or Safety Integrity Levels. There are four levels with SIL-4 meeting the most stringent criteria and hence considered the most dependable.
Becoming SIL certified is challenging because it’s based on variables in processes and estimates of reliability. This makes it difficult for the international standards organization, the International Electrotechnical Commission, (IEC) to define.
“The reason Piper was able to become safety certified is because we use proven Ultra Wideband technology as the way of positioning trains consistently and in real-time,” said Robert Hanczor, CEO, Piper Networks. “Piper has undergone years of testing and successfully passed thorough audits by safety assessor TÜV SÜD, to become the world’s first and only CENELEC SIL-4 Safety Certified UWB positioning system for rail and transit.”
Piper says it has demonstrated how its UWB technology provides a vast array of technological and cost-saving advantages over traditional or legacy positioning systems. In addition to providing location services for Communication Based Train Control (CBTC) systems being deployed on large urban rail systems, Piper’s technology supports Automatic Train Protection (ATP) systems at varying levels of complexity.
Based on the transportation agency’s requirements, Piper’s UWB system can deliver vital functionality for vehicle limits compliance, collision avoidance, civil speed enforcement and red signal overrun protection to name a few. Piper has also demonstrated how its UWB product’s small footprint can be further leveraged to provide these agencies with protection systems for maintenance of way (MOW) vehicles and their workers.
In addition, the installation of certified UWB system allows for many operational and passenger benefits. Trains can move closer together, allowing riders to get to their destinations faster with less delays. Projects like resignaling can also be completed quicker because less equipment is needed on the wayside.
Progress towards safety certification
Piper’s R&D efforts were based on feedback from TÜV SÜD and the CBTC suppliers – most recently Mitsubishi and Hitachi. They explained that in order for Piper to remain the integrator, UWB needs to be vital, meaning SIL-4 certification for every component of the system. Their preference is to provide a port for Piper to supply positioning data according to the Interface Control Documents. From an interoperability standpoint, any non-vital approach will also require substantial modifications to the standards mandated by agencies.
Achieving Vitality with the UWB subsystem will enable Piper’s clients to leverage the UWB system as the backbone to enable further enhancements to CBTC which are in line with their goals of improving service to their ridership.
