All rights reserved – Tous droits réservés - SNCF System modelling and holistic simulation Saïd EL FASSI ERTMS Project Manager SNCF Engineering All rights.

All rights reserved – Tous droits réservés - SNCF

System modelling and holistic simulation

Saïd EL FASSIERTMS Project ManagerSNCF Engineering

All rights reserved – Tous droits réservés – SNCF 17/02/2014

SNCF – DOCUMENT CONFIDENTIEL

Overview

System modelling and holistic simulation :

To optimise the design in interface with existing infrastructure systems

To identify and to confirm performance targets

To optimise cutover plan

To mitigate project risks

All rights reserved – Tous droits réservés – SNCF 17/02/2014 – page 2

Mass transportation in dense railway network

Challenges to improve the service quality in dense area of the existing railway network

Large cities as Paris, London are facing a significant increase of the transport capacity demand.

Suburban lines are crossing the city. In the core area, the passenger flow is tremendous.

Without extending the existing infrastructure, our challenge is to offer to passengers a significant improvement of the service quality by :

Increasing the transport capacity offer,

Increasing the service regularity,

Increasing the overall availability.



Passenger’s expectations

Transport capacity

Journey Time

Regularity

Challenges : How to provide the best answer ?

Constraints

How to answer?

Rules & regulati

ons

Safety

Existing system



CBTC technology but in an open railway environment?Handle the complexity without forgetting the final users’ expectations

Railway system

Rolling stock

Interlocking

TracksideOperation and

Maintenance

CBTC


CBTC in a railway system

Introducing CBTC technology in a railway system requires to visit all its components and to govern signalling revamping project through an holistic approach

Rolling out CBTC technology in a railway system is not just upgrading the signalling sub-system.

The Railway System is an entire complex system consisting of

Trackside Technical Systems

Train sets

Technical interfaces between sub-systems, components

Environment in which the system is operated

Operation rules

Maintenance policies

Human resources

The overall performances of the railway system is achieved by a system wide vision approach.


Handle complexity : Facts

Signalling systems and environment are more and more complex

Functional and safety requirements are not anymore confined in a single piece of equipment or subsystem. They are spread off between rolling stock, trackside systems,…

A tight management of the interfaces is required,

The functional allocation makes the interfaces more fuzzy,

Digital systems and distributed architecture require to manage time effects,

Operation and maintenance constraints have to be addressed,

Text-based approach proves a less efficient means of handling such complexity.

Environment

Diversity between rolling stock and trackside principles,

Diversity of signalling systems,

Diversity of geographic configurations,

Diversity of suppliers,

Difficulties to communicate between suppliers and railway experts.


Handle complexity

System performances are achieved through a global system vision

The signalling system has to be considered in the overall system with all its intricacies

The overall performances of the railway system is achieved by determining the right allocation of performance of each sub-system:

Rolling stock,

Signalling,

Headway,

Dwell time in station,

Global safety : Safe braking model, track conditions,

A global system vision approach has to be developed.

System performances Global safety

Rolling Stock

Signalling

Traction power

Track

Dwell time

Headway

Availability


Holistic approach from the definition phase up to the construction phase

Holistic approach for reducing project risks

Main goals have to be addressed

During the earliest stage of the project

Define performance requirements of main system parameters

Coordinate expert with skills in a wide range of disciplines

Get a clear cut picture of what requires modification

Define functional and technical requirements

During the project execution

Check continuously the system consistency.

Check the cutover program and its performance

Detect at the soonest non compliance

Requirements Performance allocations

Definition phase

What we are expecting

System performances

Construction phase

What we get


Holistic approach and system requirements

Key to success : Model-based system approach as a collaborative tool with suppliers and partners

Our approach is to develop a model-based system design methodology starting from the earliest stage of the project

Determine performance allocation

Build up models of existing signalling system

Build up kinematic model for rolling stock

Build up models of functional requirements

Follow a continuous refinement and improvement of models

Use of models to validate interface specifications

Use of models to proof safety requirements

Connect all models

Connect model based design and Hardware in the Loop

Setup a versatile system integration platform

Check & proof

Refine

Specify


Holistic approach and system requirements

Key-success : Model-based system approach as a collaborative tool with suppliers

Three examples of model based system approach

System performance allocation

Signalling model

System integration platform


Performance allocation

Performance allocation is a key project driver

Performance allocation thanks to simulation tool allows assessment of :

Sensitivity of the various parameters

Safe braking model parameters

Braking capability

Propulsion capability

Degraded modes

Response times of the different systems

Traffic regulation margins

Energy consumption optimisation

Modes of operation

Final choice is governed by the best balance between

CAPEX

OPEX

Performance achievement


Signalling Interface management

Model of Interlocking provides system assurance

PRCI Interlocking is a relay based technology

Using such interlocking in the CBTC environment requires some adaptation.

The main goal is to switch from a functional specification to a dynamic model in order to

Make available an interlocking with a real behaviour

Define and check the modification at the interlocking level

Introduce the model in CBTC and system integration platform

Define and check all migration phases of the interlocking

Assess performances of each migration phase


Interlocking environment

Interlocking modelling principles

MES / TRI

SNCI/SNCO

Interlocking

Trackside equipment

MMI command/control

Adjacent interlocking

Switch Track Circuit

Signal

Part included in the model

Environment• Point machines• Signals (nominal and degrade modes)a, • Track circuits

Trackside status behaviour

User’s interface : allows to command and to control the interlocking

Adjacent interlocking


Interlocking

Sample of cabling


Interlocking environment

MMI for trackside components and commands and controls of routes


System integration platform

The integration of the system follows the system development cycle

Tender specifications

Environment models Reuse of environment modelsRefinement

Models during system design

HIL system integration


Global system vision through modelling

Model-based system approach as a collaborative tool with partners and suppliers

Our first lessons

Model-based approach launched in the early phase of the project provides means :

To define more accurately the system and its interfaces

To clarify the behaviour of the system

To locate and to correct non conformance along the design and construction phases and not at the end of the project

To communicate and to share with external partners and to create more efficient supplier relationships.

To get a better vision at project management level


Global system vision through modelling

Model-based system approach increases the efficiency of the project

Our first lessons

Model-based approach increases the efficiency of the project by :

Reducing on site and dynamic testing costs : dynamic testing is focused on the verification of real time constraints,

Giving a clear guide of the project’s testing plan,

Providing a clear vision of the status of the project : the validation of functional requirements in advance of the design phase clears specification’s uncertainties,

Reducing project’s risks and providing a better assurance in project’s risk assessment

Securing the overall project schedule: clearance of technical risks in the early stages of the project procures margins for optimizing the overall schedule.


SNCF – DOCUMENT CONFIDENTIEL

Thanks for your attention


All rights reserved – Tous droits réservés - SNCF System modelling and holistic simulation Saïd EL FASSI ERTMS Project Manager SNCF Engineering All rights.

Documents

signalling subsystem

trackside systems

entire complex system

open railway environment

system wide vision approach

maintenance cbtc

digital systems

environment diversity