Modernising legacy signalling systems with CBTC technology
Future-proofing communication-based train control architectures
Migrating to new signalling systems without disrupting service
Improving operational performance with automation
Rail Signalling Systems Conference, Trueventus
November 10, 2021
legacy signaling systems with CBTC technology CBTC and interoperability Train-to-wayside communications Train localization technologies CBTC system architectures Train detection and train integrity CBTC migration strategies Automation and conversion to driverless operations Systems engineering approach to signal modernizations 2
3 Computer-aided dispatch / automatic vehicle location system low speed, drive on sight operations difficult to automate, sharing the right of way with road vehicles and pedestrians CAD/AVL Communication-based train control high-frequency operations: designed for up to 60 trains / hour automation to enable high- frequency operation, including unattended train operation precision stopping at platform screen gates CBTC European Rail Traffic Management System ETCS Level 2 + ATO lower frequency suitable for fixed block operation, no more than 20 trains / hour automatic train operation performance still limited benefit from interoperability between suppliers ERTMS Streetcar, tramway, light rail Automated people mover, monorail, metro, heavy rail Airport express railway, commuter rail
automatic train control systems European Rail Traffic Management System, Chinese Train Control System (CTCS) Designed for interoperability, deep network of suppliers 4 U.S. Positive Train Control Three competing systems: I-ETMS, ITCS, ACSES Limited number of suppliers Mostly proprietary designs and interfaces, suitable to closed systems 20+ suppliers worldwide ERTMS PTC CBTC
initiatives Open Control of Trains, Interchangeable & Integrated System (OCTYS) Approach: interchangeable subsystems Interoperability Interface Specifications (I2S) Full interoperability between three qualified suppliers I-CBTC deployed in various cities: Chongqing, Urumqi, Qingdao, Guiyang Standardized onboard-wayside interface wayside-wayside interface vehicle interface driver-machine interface wayside components and installation constraints electronic track map CBTC and interoperability
6 Voice TETRA or P25 Train Control Wi-Fi #1 Passenger connectivity 5G mmWave and LTE PA/CIS + CCTV Wi-Fi #2 Vehicle diagnostics LTE Voice TETRA or P25 Train Control Passenger connectivity (and LTE) PA/CIS + CCTV Vehicle diagnostics Single Wi-Fi network common train-to-wayside communication infrastructure New radio technologies meet the diverse data transmission requirements of rail systems train control – high availability, low latency, low throughput CCTV – high throughput, OK to delay transmission
Traditionally o wheel sensors o relocation beacons o (maybe) doppler radar New options available o inertial measurement units o satellite navigation o radio ranging o LiDAR 7 Improved train localization o shorter headways o faster approach to stations o better stopping precision Reduced equipment on the wayside and on the train o faster installation o less maintenance o equipping the yellow fleet Common positioning infrastructure shared with other applications o worker protection o maintenance operations
with GNSS The CLUG Project 8 The CLUG Project – Certifiable Localisation Unit with GNSS in the railway environment Deliverable D3.4 – GNSS Augmentation Needs for Rail
localization Ultra-wideband radio ranging 9 New York MTA pioneering the replacement of legacy transponders with UWB radio beacons on upcoming CBTC modernization projects UWB ranging provides a precise distance between the train and beacons installed along the tracks Train precisely localized via triangulation
vs. centralized 10 Central control center Central control center Signal equipment room Signal equipment room 10 Central Control ATC/CBI Object Controller Object Controller Object Controller Object Controller ATC/CBI Central Control Object Controller Object Controller Object Controller ATC/CBI Object Controller reduced signalling equipment footprint, easier and faster to deploy – higher RAM performance in many cases 1 2
rooms Station control rooms Central control center Wayside Track bed CBTC system architecture Secondary train detection Object controllers Transponder interrogator Driver machine interface Wheel sensors Onboard ATC computer Train-to- wayside radios Automatic Train Supervision Interlocking computer Automatic train control zone controller Station control workstations Switch machines Relocation transponders Signals Train-to- wayside radio access points Maintenance workstation
rooms Station control rooms Central control center Wayside Track bed CBTC system architecture – simplified Secondary train detection Object controllers Transponder interrogator Driver machine interface Wheel sensors Onboard ATC computer Train-to- wayside radios Automatic Train Supervision Interlocking computer Automatic train control zone controller Station control workstations Switch machines Relocation transponders Train-to- wayside radio access points Signals Maintenance workstation
detection Track circuits and axle counters expensive to deploy expensive to maintain – track circuits require periodic tuning and get stolen often decrease overall system availability but facilitate the migration from legacy signaling to CBTC offer a backup when CBTC radios fail allows for unequipped work trains track circuits offer some level of broken rail detection secondary train detection of choice for CBTC upgrades can be overlaid over legacy track circuits, facilitating migration long axle counter blocks can lower the amount of equipment deployed more flexibility in installation and modification no periodic tuning required ultrasonic inspection regime to mitigate lack of broken rail detection Axle Counters
Train detection and train integrity Modern electric multiple units: TCMS guarantees the integrity of the train consist Overhauled legacy rolling stock: a new train backbone network might ensure train integrity Work trains: unequipped wagons will need to be protected by two CBTC-equipped locomotives Unless a removable end-of-train device – compatible with the CBTC system – gets installed Unitary rail vehicles need to be fitted with a protection system compatible with CBTC 15 CBTC CBTC CBTC CBTC CBTC CBTC CBTC EOT
New CBTC system deployed on top of the existing legacy signaling – sharing only signals and switch machines Allows for testing the new CBTC in shadow running mode 1. train detection 2. train localization 3. train-to-wayside communications 4. environmental conditions 5. reliability and availability 6. data configuration 7. train supervision 16 Easier to overlay if no interference between components: Legacy ATC CBTC track circuits axle counters RFID transponders ultra-wideband (UWB) radios wheel sensors inertial measurement units (IMU) speed codes through track circuits free propagation Wi-Fi data communication CBTC migration strategies
strategies Dual-equipped train in CBTC mode Dual-equipped train in legacy ATC mode Dual-equipped trackside in CBTC mode Dual-equipped trackside in legacy ATC mode Dual-equipped trackside with both legacy ATC mode and CBTC active Train running in legacy ATC mode Train running in CBTC mode
strategy: full switch for line extension Benefit no need to install legacy signaling on new extension 0 1 Deploy CBTC on the extension 2 Expand CBTC to the older line 4 Decommission legacy ATC Train running in legacy ATC mode New extension fitted with CBTC Dual-equipped train in CBTC mode Dual-equipped train in legacy ATC mode Legacy ATC removed, train running in CBTC mode
strategy: mixed operations for new fleets 1 Overlay CBTC on top of legacy signaling 2 Introduce the new fleet in CBTC mode, keeping the old fleet with legacy ATC 3 Once the two fleets are equipped with CBTC, decommission the legacy ATC Benefits no legacy ATC to install on the new fleet no CBTC to install on the old fleet if it is to be replaced Old fleet running on legacy ATC Old fleet running on legacy ATC Trackside CBTC installation New fleet running in CBTC mode Dual-equipped trackside with both legacy ATC mode and CBTC active Dual-equipped old fleet running in CBTC mode Removing the legacy ATC trackside equipment
driverless train operations * from UITP Observatory of Automated Metros, Statistics Brief, April 2019. With the addition of Copenhagen Fremtidens S-bane (confirmed) and London Piccadilly Line (to be confirmed) Successful conversion of Nuremberg in 2009 and Paris Line 1 in 2012. Conversion projects* in Europe: o Brussels, L1 and L5 o Copenhagen Fremtidens S-bane o Glasgow, G. Subway o London, Docklands and Piccadilly o Lyon, LA and LB o Marseille, L1 and L2 o Paris, L4 o Vienna, U2/U5 Automation of metro operations
just upgrading signaling and train control systems Key consideration: track intrusion detection and obstacle detection 22 Figure 13: Platform Screen Doors vs. non-PSD (total stations equipped and % of new stations in the last decade) UITP Observatory of Automated Metros, Statistics Brief, April 2019 Converting to driverless train operations
of systems engineering Life-Cycle Cost Impacts from Early Phase Decision Making Cost Saving Losses multiply as a project progresses. Solving issues early reduces this impact Understanding what is required early is key to avoiding surprises later Systems engineering approach to signal modernizations
engineering approach SI:D3 Systems Integration 1. Develop the strategy 2. Define the system 3. Deliver integration Systems engineering approach to signal modernizations
legacy signaling systems with CBTC technology benefit from advances in wireless comms, computer vision benefit from advances in networking and computing capacity anticipate future procurements, system expansion evolutions required on other rail systems: rolling stock, comms performance gains from higher level of automation deployment strategy to mitigate risk and impact on operations 26 Technology Architecture Standards Interfaces Automation Migration
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