Transit Systems Tapping Ultra Wideband Technology to Improve Signaling

Many of today’s transportation systems are reaching a critical inflection point in their ability to expand to meet the demands of growing populations. Large urban centers such as New York City, London, and Singapore are experiencing unique challenges compared with smaller cities or those with more modern infrastructure. Considering the amount of daily traffic, the aging signaling equipment infrastructure, and the absolute breadth of the system, it’s critical that these cities explore the advantages of technologies that can help take giant leaps forward. 

For many transit agencies around the world, Ultra Wideband (UWB) radio frequency technology can be an important evolutionary shift towards improving signaling, train control systems, and bus operations. The move from track circuits and roadbed transponders to radio communication positioning creates an important stepping stone to the future of fully vehicle-centric systems. Companies investing in UWB technology face certain challenges such as interoperability with competing vendors and adapting to unique protocols adopted by various agencies. Additionally, UWB systems must be safety certified before they can be deployed in revenue service. Notwithstanding these hurdles, UWB provides benefits that encourage many transportation agencies to consider the technology as part of their system enhancements. 

How it Works 

UWB uses narrow radio frequency pulses to wirelessly communicate between the train and small devices installed on the wayside. Using a method known as Time-of-Flight to measure the time it takes for signals to be sent and received, the distance between the radios can be instantly captured. As the train moves along the track, its exact position is calculated 10-15 times each second by an onboard computer with exceptional accuracy and reliability. 

Ultra Wideband Application in Signaling 

UWB technology determines the location of transportation vehicles with unmatched positional certainty. The system is like a blanket of radio coverage over the subway lines - virtually surrounding the tracks with smart sensors that pinpoint train location down to a few inches. To date, UWB programs initiated within the transportation industry have focused on assessing the reliability, interoperability, and safety certifiability of technology. Because UWB equipment is installed on the wayside and in the interior control cabinets on the train (as opposed to the track bed and the undercarriage of the rolling stock), the positioning systems required to manage train headways can be deployed faster, at lower cost, and with minimal disruption. For transportation agencies or railroads who are installing Communications Based Train Control systems (CBTC), Positive Train Control (PTC) systems, or performing midlife enhancements to existing systems, UWB offers several valuable benefits including: 

1. Increasing System Throughput 

Ultra-precise positioning improves headways, allowing trains to run closer together and more frequently. The result is increased capacity that improves on-time performance and overall customer service. Similarly, as Bus Rapid Transits look to introduce Platooning features, UWB technology vitally tracks the position of the equipped busses and the distance between two or more equipped busses. 

2. Improving Maintenance, Increasing Performance, and Reducing Cost 

UWB equipment is installed along the wayside, not in the track bed, making installations safer, faster and easier to maintain with greater reliability for riders. By using wayside equipment, UWB technology can also be more affordable to install since it builds off the existing infrastructure instead of requiring new locations for installation, power, and connectivity. In cases where CBTC has been integrated with UWB, UWB technology has proven to accelerate the installation times and performance of CBTC systems. This integrated approach has the potential to reduce the delays often associated with retrofitting existing rail lines (brownfield installations) and can improve the overall reliability of the system. 

3. Providing a Vital Positioning Subsystem 

As many PTC systems around the United States are reliant on GPS and wheel tachometers for localization and odometry functions, many railroads are finding that wheel slips, underground operations, and navigating through dense city environments often proves too challenging for the systems of today to handle. Integrating UWB into existing PTC systems would allow the PTC systems of today to improve the railroads operational efficiency and improve upon the safety of its operations by decreasing instances of delocalization.  

The innovative new application of UWB technology has the potential to profoundly improve the life of commuters, especially as urban populations are expected to grow exponentially in the coming decades. Incorporating new technologies like UWB into existing and new signaling equipment, urban transit agencies will be able to meet the challenges of rail systems’ expansion directly - improving the customer experience while helping reduce overall cost.

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Robert Hanczor is the CEO of Piper Networks, an innovative IT solutions provider and systems integrator specializing in the transportation industry. Piper has just successfully completed its third implementation with UWB on the NYCT Subway System.