Architecture (AR)

Aatish Mishra
Aatish Mishra
Last updated 
  • The current scenario for train control and signalling systems is fragmented. As a result, there is a need to establish a reference architecture that Infrastructure Managers (IM's) can refer to while building their Control Command and Signalling (CCS) systems. 
  • This will be achieved by evolving existing CCS solutions by: 
  1. Introducing standardized future-proof interfaces such as ETCS and EULYNX, that facilitate modularity, migratibility and adaptability. 
  2. Inclusion of 'Game-changers' namely ATO, train-borne localization, etc.

Current Scenario 724 KB View full-size Download

Scope of the cluster:

  • The cluster aims to define the reference architecture in terms of its systems, interfaces, function apportionment, and non-functional requirements.
  • The architecture shall be derived from RCA Goals in a comprehensible and traceable way. Main structure for this is provided by a layered model. 
  •  The reference architecture will result in a model and a set of concept and  specification documents.
  • The architecture should account for the following:
  1. The architecture shall be derived from RCA Goals in a comprehensible and traceable way.
  2. Although the reference architecture depicts a target architecture it should also be able to support stepwise migration.
  3. Prevent functional diversity - every function is designed only once- More diversity means more complexity and more costs. This ensures alignment and functioning interaction of the concerned systems.
  4. Reduction of trackside assets. Leads to reduction of LC costs and increases reliability.
  5. Modularity - components should be exchangeable. Requires interfaces that allow upward and downward compatibility. 
  6. Functions are to be allocated to software which should also have the possibility to be automated.
  • Below figure depicts the systems involved within the reference architecture with respect to functions separated into layers. The components for these functions are assigned to exactly one layer. 

Scope and Layers of the Reference Architecture 95.5 KB View full-size Download
  • The functions within these layers are described below:
  1. Planning (not in scope of RCA): Creating the plan for customers and for production (Operation Plan).
  2. Movement Control: These functions implement the operation plan by issuing 
    single object-control requests (OCRs) when the condition regarding the current operational status are met. These OCRs can, for example, change a switch position or update a movement permission.
  3. Safety Control: These functions check requests from upper layers or users: If they are in a safe state, then they are executed. They also check events and overall status of all objects and invoke emergency reactions for unsafe situations.
  4. Object Aggregation: These functions combine devices for an abstracted object representation. They co-ordinate devices (actors) for the execution of object-control commands, which should work “hand-in-hand”.
  5. Device Abstraction: These functions offer abstracted device capabilities (functions and information) and an abstracted device access (e.g., topology-related).   
  6. Device Control: The device-control functions steer and administrate devices. They assure the quality of the de- vice control. They  offer easy access to  devices via data network for the layer above.
  7. Devices (not in scope of RCA): e.g. Train Driver, Field Elements, etc.

  • The below figure illustrates the reference architecture showing its main interfaces and subsystems for GoA1/GoA2. 
  • It depicts the various architecture layers as described above. Each layer consists of one or more systems that interact with each other through interfaces.
RCA Logical Architecture (Please view in full size) 120 KB View full-size Download
  • A more detailed description of various components and interfaces for the above figure are given here:
  1. Abbreviations:
  • SCI: Standard Communication Interface
  • SDI: Standard Diagnostic Interface
  •  SMI: Standard Maintenance Interface
  • SAI: Standard Authentication/Authorization Interface
  • SWI: Standard Workbench Interface
  • SHI: Standard Handover Interface
  • AoE: ATO over ETCS
  • SS: CCS TSI ETCS Subset
2. Actor Descriptions:
  • Railway Operator: The Railway Operator manages, directs and facilitates the movement of trains over an assigned area.
  • Asset Manager: The Asset Manager provides all relevant infrastructure data and manages this data. 
  • Sys Admin: Sys Admin is responsible for the technical operation and maintenance of the RCA systems.
  • Field Element: Railway fixed equipment on/or adjacent to track, e.g. light TDS, Point, etc.
  • Authorized Trackside Person: Trackside Person is a person working on the construction or maintenance of the trackside infrastructure.
  • Mobile Object: An object that is reporting to RCA system but is not able to be controlled directly by RCA, e.g. construction equipment. 
  • Train Driver: A person capable and authorized to drive trains
  • Physical Train Unit: A Physical Train Unit can be a train unit, consist or a vehicle
3. System Descriptions:
  • Planning System (PAS): The planning system for the traffic management. 
  • Plan Execution (PE): PE translates operational plans into discrete requests for movement permissions and state changes of abstract objects representing Field Element. 
  • ATO Execution (AE): AE translates operational plans into journey profile for automatic train operations.
  • Safety Logic (SL): SL grants or rejects requests for state changing of either a Field Element or for a planned movement, based on a safety evaluation.
  • Safety Manager (SM): SM monitors the state of the railway operation, recognizes hazardous combinations of states, and triggers safety reactions.
  • Object Aggregation (OA): OA routes and aggregates abstract commands to the transactors and aggregates state from into abstract representations of the state of the railway operation.
  • ATO Transactor (AT): AT distributes automatic train operation journey profiles, to the on board unit of individual Physical Train Units.
  • Movement Authority Transactor (MT): MT translates commands and state feedback between the device-specific track-train message set specified.
  • Mobile Object Transactor (MOT): MOT translates between the abstract objects used by the Object Abstraction Layer and the device-specific commands and vice versa.
  • Fixed Object Transactor (FOT): FOT translates between the abstract objects used by the Object Abstraction Layer and the device-specific commands from EULYNX subsystems and vice versa.
  • ATO Vehicle (AV): AV executes journey profile packet and segment profile packet by controlling the physical functions of the Physical Train Unit.
  • Vehicle Supervisor (VS): SubSys VS implements the supervision part of the ETCS on board unit. 
  • Vehicle Locator (VL): VL uses mobile localization technology to safely and reliably provide position, length and speed information of the train.
  • Mobile Object Locator (MOL): MOL provides the position of a trackbound or non-trackbound object on the railway network topology.
  • Person Supervisor & Locator (PSL): PSL provides additionally to MOL warnings and protection from approaching movable objects.
  • Point (P): P is used to control and monitor the Point machines of movable elements based on a request from the FOT.
  • Level Crossing (LC): The LC protects the crossing area of rails and vehicles through its level crossing protection facility.
  • Train Detection System (TDS): TDS monitors the vacancy and occupancy status of TVP sections.
  • Light Signal (LS): LS transmits information to Train Driver. 
  • Generic IO (IO): IO is used for integrating signalling systems, controlled and monitored by FOT. 
  • Workbench (WB): WB is a platform for providing process specific user interfaces.
  • Engineering & Data Preparation (EDP): EDP support commissioning and maintenance processes.
  • Topo4: Topo4 provides a correct, validated topology and topography data for SIL4 systems.  
  • Safe Reflexive Reaction Controller (SRRC): SRRC decides if a hazard is caused by an object which is recognized in front of the Train Unit.
  • Device and Config Management (DCM): DCM is used to register, setup and manipulate Devices.
  • Diagnostic & Monitoring (DM): DM collects monitoring and diagnostics information from subsystems.
  • Identity & Access Management (IAM): IAM authenticates and authorizes users and technical systems and grants or denies access to the system.
  • Evaluated Train Manager (ETM): ETM registers and monitors multiple Events and relevant data to compute and classify Incidents for the respective Train Unit.
  • Evaluated Reaction Manager (ERM): ERM aggregates, maps and monitors multiple Events and relevant data and classifies Incidents with deterministic rules.
  • Train Front Monitor (TFM): TFM monitors the defined area by detecting, analysing and classifying specified objects, infrastructure and Events.
  • Impact Detection (IMP): IMP detects an impact with an object at the Train Unit Front End and measures the force and location of the impact, for later Incident Reactions.
  • Train Interior Monitor (INT): INT monitors the Passenger Crowds in defined areas in a Train Unit.
4. Interface Descriptions:
  • SCI-OP: Operational Plan Interface
  • SCI-CMD: Command Interface
  • SCI-AO: Abstract Object Interface
  • SCI-AD: Abstract Device Interface
  • SCI-MD: Mobile Device Interface
  • SCI-VL: Vehicle Locator Interface
  • SCI-PS: Planned State  
  • SCI-OP: Operational State
  • AoE SS-131: CCS TSI ATO over ETCS SUBSET-131
  • AoE SS-126: CCS TSI ATO over ETCS SUBSET-126
  • AoE SS-130: CCS TSI ATO over ETCS SUBSET-130
  • AoE SS-132: CCS TSI ATO over ETCS SUBSET-132
  • SHI-PE: PE Handover Interface
  • SHI-SL: SL Handover Interface
  • SHI-SM: SM Handover Interface
  • SHI-MOT: MOT Handover Interface
  • SHI-MT: MT Handover Interface
  • P1: Legacy Interface
  • R1 TBD x: Legacy Interface To be defined

Useful Documents/Deliverables:
Deliverables from RCA Gamma:
  1. RCA Architecture Poster 
  2. RCA Concept: Architectural Approach and Systems of Systems Perspective
  3. RCA Concept: Informal Architecture Overview 

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