The Metropolitan Transportation Authority (MTA) in New York was facing a very big challenge with its New York City Transit (NYCT) subway system of aging infrastructure, similar to other large cities around the world…
With one of the oldest metro systems in the world, New York’s signalling technology was in particular need of refurbishment; some of the wayside equipment currently in operation has been in use since the 1930s; the oldest subway cars currently in use are from the 1960s.
Brownfield resignalling projects are complex and take time, especially in New York where trains interoperate on multiple subway lines. Some estimates said it would take as much as 50 years to resignal the New York system, but not less than 10-15 years. This caused the MTA to start looking for technological advancements that could make resignalling more efficient.
Positioning is one of the key components of a new Communications Based Train Control (CBTC) system. Traditionally wheel mounted speed sensors and a transponder interrogator would be installed in the train undercarriage, with transponder tags installed in the track bed in order to initialize and maintain position. On 23 January, 2020, a new type of positioning system, utilizing cutting edge sensor technology and not requiring any equipment installation under the train or in the track bed, was fully integrated with CBTC and Automatic Train operation was successfully demonstrated in New York City at an industry-first event.
Background: The MTA’s genius transit challenge
In 2018, Thales was selected as one of the winners in the signalling category for the MTA’s Genius Transit Challenge, which aimed to find innovative solutions to the MTA’s modernization timeline challenges, enabling faster implementation. The main goals of Thales’ Train Autonomy Platform and proposed Next Generation Positioning (NGP) for signalling systems were quicker deployment and a more accurate train positioning. Rapid implementation, achieved through a reduction of wayside equipment and removal of undercarriage installation, would enable the MTA to modernize their aging subway infrastructure on an accelerated timeline. Increased train positioning accuracy, achieved through utilization of modern onboard sensors including Ultra Wide Band (UWB) radios, will contribute to fewer service delays for passengers.
Following this achievement, Thales worked with the MTA to install a system, which utilized modern onboard sensors, including radars, cameras and LIDARs, integrated with a UWB network, on a test train. In June 2018, the successful demonstration of the system’s functionality brought the dream of the Genius Transit Challenge to life. The current pilot program continued the work with the next step in the development and testing both of this new train control technology in New York City and with additional optical sensors capabilities that will further enhance safety and operability.
Benefits of next generation positioning
The NGP system has the following benefits over the currently used signalling technology:
• Rapid Deployment – The NGP system does not require any equipment to be installed in the undercarriage of the train, nor in the track bed, which would enable faster deployment.
• Start-up Position Initialization – On power up, the NGP system tells the onboard controller precisely where it is located. This enables a train to initialize and switch to Automatic Train Operation (ATO) faster than the current generation CBTC systems.
• High Accuracy & Availability – The new positioning system provides greater positional accuracy and can support much greater separation between wayside landmarks. This means that future CBTC systems based on this technology will support more precise station stopping accuracy and will be able to travel greater distance between wayside landmarks. If any element of the positioning system fails at one end of the train, the on-board controller can seamlessly switch over to inputs from the other end of the train. All of these features will contribute to faster system deployment and more reliable service with fewer delays for passengers.
Pilot in New York
On 23 January, 2020, Thales demonstrated their Next Generation Positioning (NGP) system that was part of a nine-month pilot project to develop new technologies that would deliver train control systems faster and more reliably. In March 2019, New York City Transit (NYCT) selected Thales to lead the Train Control System Pilot Program, in partnership with Piper, to determine the feasibility of Ultra-Wideband (UWB) enabled signalling technologies and deployment strategies that would reduce their subway modernization timeline.
The pilot program assessed the long-term reliability and safety of a UWB enabled signalling system by leveraging the Thales Next Generation Positioning (NGP) system integrated with Piper UWB radio technology for a full-scale evaluation of the benefits of next generation positioning technologies integrated with Communication Based Train Control (CBTC). With a smaller technology footprint, this new train control technology has the potential to be implemented faster on revenue and non-revenue trains.
There are five high-tech components/sensors that are integrated in Thales’ NGP system and were installed onboard trains as part of the Pilot Program (see also Diagram below). The five sensors are as follows:
• UWB: stands for Ultra-Wide Band. UWB is a type of radio communications that uses a very low amount of energy with short-range, high bandwidth waves using a wide range of the radio spectrum. Piper UWB radios were installed on the train and near the wayside (beside the tracks) for the NGP system. The NGP system uses the UWB to periodically receive location updates. No continuous UWB wayside coverage is required.
• IMU: stands for Inertial Measurement Unit. It detects changes in speed and direction with an extraordinary level of accuracy. The NGP system uses the IMU for: inertial navigation and orientation verification in areas where no UWB beacons are located.
• Radar: short for ‘radio detection and ranging’ Radar uses radio waves to measure the distance and speed of objects. Radar is used by the NGP system for: speed measurement and zero speed / stationary status. In a subsequent release of the Train Autonomy Platform, it will also be used for the object detection function.
• LiDAR: stands for “light detection and ranging.” LiDAR uses pulsed laser light to measure distance with high precision to any targets within range to create a dense 3D map of its surroundings. LiDAR was used to scan the train route and create a “ground truth” digital map that positioning system data can be compared with.
• Camera: using advanced image processing techniques, the camera can detect objects such as rails, wayside equipment, or trackside workers. These functions are still in the preliminary testing phase and were not used by the NGP processing for positioning.
The Ultra-Wideband (UWB)-based Train Control System Pilot Program has proven that Thales’ NGP (Next Generation Positioning) system is accurate and robust and can be integrated with an existing CBTC system. This project is a successful step in the path to a safety-certified NGP system. The NGP system’s high-tech features will contribute to faster system deployment and more reliable service with fewer delays for passengers.
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