Human Factors in the Development of Safety-Critical Railway Systems - PowerPoint PPT Presentation


PPT – Human Factors in the Development of Safety-Critical Railway Systems PowerPoint presentation | free to download - id: 5b78fd-OTNhM


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation

Human Factors in the Development of Safety-Critical Railway Systems


Human Factors in the Development of Safety-Critical Railway Systems Simon Zhang, Technical Director, Lloyd s Register Rail (Asia) Ltd * * Human factors is about ... – PowerPoint PPT presentation

Number of Views:148
Avg rating:3.0/5.0
Slides: 26
Provided by: shis150


Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Human Factors in the Development of Safety-Critical Railway Systems

Human Factors in the Development of
Safety-Critical Railway Systems
  • Simon Zhang,
  • Technical Director,
  • Lloyds Register Rail (Asia) Ltd

Factors affecting Safety Critical System
1. Management systems and processes to safely
guide and control business activities
The Equipment
The System
2. Capable and competent people and culture to
deliver safety objectives
The People
IRSC 2012 Conference
Human Errors in the Railway World
  • Human errors can be costly and/or fatal

IRSC 2012 Conference
System Lifecycle
Where do human errors occur in the development
lifecycle? What type of errors occur why? How
can they be addressed?
IRSC 2012 Conference
Strategies for addressing Human Error in System
  • EN50126 Guidelines
  • Human competency
  • Human independence during design
  • Human involvement in verification and validation
  • Interface between human and automated tools
  • Systematic failure prevention processes
  • Application of EN50126
  • Competency is a prerequisite
  • Education and training are assumptions

IRSC 2012 Conference
EN50126 Process Framework
IRSC 2012 Conference
EN50129 View (1)
  • Safety Organisation

IRSC 2012 Conference
EN50129 View (2)
  • Systematic failure prevention processes

IRSC 2012 Conference
EN50129 View (3)
  • Human Involvement in VV

IRSC 2012 Conference
Limitations of Process-Based Standards
  • Incompleteness of processes
  • Inadequate guidance on human factors in system
  • Questionable rationale for SIL and Processes
  • The processes for higher SIL may not produce
    safer products or systems
  • Applicability of standards
  • Well understood problem domain
  • Risk totally covered
  • Mature project and safety organisation

IRSC 2012 Conference
Yellow Books View
  • Compliance based approach
  • Using existing standards as the driver to develop
    and evaluate a system
  • Risk based approach
  • Using risk assessment as the driver to develop
    and evaluate a system

IRSC 2012 Conference
Assessors View (from LR Rail experience)
IRSC 2012 Conference
Emerging Themes from Assessments
  • Mainly from the Chinese railway signalling
    industry in recent 3 years
  • 20 Chinese companies
  • 30 RPC projects
  • 10 ISA projects
  • Aim to explicitly identify and evaluate the
    underlying risk associated with known human
    factors in system development
  • Using EN50126/9 standards as a starting point
  • Several themes emerged from the studies relating
    to human errors human factors

IRSC 2012 Conference
Chinese Railway Signalling Industry
  • China has experienced a large number of railway
    construction projects in both high speed mainline
    and metro systems
  • Lessons from last years 7.23 railway accident
  • Due to serious design flaws in control equipment
    and improper handling of the lightning strike
  • Personnel competency is questionable
  • Re-examine existing safety management systems and
    development processes

IRSC 2012 Conference
Initial Findings Theme 1
  • Human competency
  • Undefined competence requirements on many roles
    such as verifier, validator and safety engineer
  • Training and qualification records may not be
  • Certified or qualified training and education
    institutes are required
  • Domain knowledge and experience are more
    important and can be easily verified via
  • Organisational culture and HR policy can also
  • Difficult to keep capable safety engineers

IRSC 2012 Conference
Initial Findings Theme 2
  • Human Independence during Design
  • Organisational structures
  • E.g. rigidly hierarchical structures
  • Leadership patterns
  • Two extremes
  • Responsibilities and roles
  • Incorrect understanding of allocated
    responsibilities and authority control

IRSC 2012 Conference
Initial Findings Theme 3
  • Human Involvement in VV
  • Undefined competence requirements on many roles
    such as verifier, validator and safety engineer
  • Lacking domain knowledge from the verifier or
  • Misunderstanding the role of VV
  • Lack sufficient project resources for VV
  • Tight project schedule

IRSC 2012 Conference
Initial Findings Theme 4
  • Interface between Human and Automated Tools
  • Undefined competence requirements on the tool
  • Lacking of guidance on safety analysis over the
  • Difficult to have a systems approach
  • Viewing the tool and tool user as a complete
    system in a context of a project

IRSC 2012 Conference
Initial Findings Theme 5
  • Systematic failure prevention processes
  • Inadequate guidance on techniques/measures
    recommended from standards
  • linking techniques/measures with a level of
    recommendations does not help
  • Tactic knowledge is required
  • Undefined competence requirements on many roles
    such as verifier, validator
  • Safety management system may also help
  • But there is lack of guidance from the standards

IRSC 2012 Conference
Enhancing assessments to evaluate human factors
  • Is there good
  • working culture?,
  • leadership?
  • motivation?
  • Are roles, responsibilities authorities

Can people reach everything? Is there enough
space to work? Are there obstructions? Can a good
working posture be achieved?
Can procedures be followed? Is there time
pressure? What working hours or breaks? What
training is given? What level of supervision is
there? What competence is required are these
well defined? Processes for using tools well
developed? Is there understanding of safety
Is the machine/tool easy to use? Is the behavior
of the tool understood by user? What happens if
the tool fails (e.g. during VV)? Is it available
where it is needed? Does the interface meet
Is the lighting OK? Is noise a distraction or
does it prevent good communication? Does the
temperature make people tired?
  • What attributes does a person need
  • good vision/hearing,
  • strength,
  • particular skills,
  • personality traits
  • motivation?
  • Qualifications experience
  • Domain knowledge

How can we bring these into the assessments?
IRSC 2012 Conference
Evolution of the Standards
  • Introduction of EN501282011 Standard
  • Definition of 10 roles including verifier and
  • Guidance on support tool for software development
  • Focus on tool validation and tool specification
  • New development on EN50126/9 standards in the
    near future
  • Merging the EN50126/8/9 standards together
  • The role and competence requirements of safety
    engineer need to be defined
  • More guidance on using the HR/R
  • Develop guidelines on the SMS (safety management
  • Interface between human and tools needs to be

IRSC 2012 Conference
Future Work
  • Get feedback on the viability and effectiveness
    of the approach
  • Conduct more empirical studies from other
    geographical areas such as Hong Kong, Taiwan,
    Korea and India
  • Define robust human factors evaluation framework
  • Consider ranking or quantitative assessment
  • Provide input to the development of new
    EN5016/8/9 standards
  • Industry research into root causes of Human
    Errors during system design

IRSC 2012 Conference
  • Do not take human competency for granted
  • Company/project management styles can always
    influence human independence
  • Human judgement determines the VV success
  • Interface between human and automated tools can
    be unexpectedly complex
  • Understanding the rationale behind
    techniques/measures is more important than
    choosing which in the systematic failure
    prevention processes.

IRSC 2012 Conference
  • Human error plays a part in most, if not all,
    accidents. If you have not considered human error
    when specifying your work, it will be difficult
    to show that you have controlled risk to an
    acceptable level.
  • Human error has causes. We understand some of
    these and know how to prevent them. When
    designing railway systems you should look for
    opportunities to prevent human error leading to
    an accident.

IRSC 2012 Conference
(No Transcript)