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Research Programme

Operations

Development of SPAD risk management tools


Development of SPAD Risk

Management Tools - Summary Report

for RAIL SAFETY AND STANDARDS BOARD

REFERENCE: HEL/RSSB/051333b/RT1

CLIENT REFERENCE: T435

DATE: 10th May 2006 ISSUE: 01

Human Engineering Limited

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www.humaneng.co.uk


HEL/RSSB/051333b/RT1 Issue: 01

10th May 2006

16.8 Copyright

Research reports submitted to RSSB shall include in a prominent position within the

first two or three pages of the report the following copyright statement:

‘© Copyright 2006 Rail Safety and Standards Board.

This publication may be reproduced free of charge for research, private study or for internal circulation

within an organisation. This is subject to it being reproduced and referenced accurately and not being

used in a misleading context. The material must be acknowledged as the copyright of Rail Safety and

Standards Board and the title of the publication specified accordingly. For any other use of the

material please apply to RSSB's Head of Research and Development for permission. Any additional

queries can be directed to research@rssb.co.uk. This publication can be accessed via the RSSB

website www.rssb.co.uk

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ACRONYM LIST

HFP

PSF

RHC

RSSB

SHC

SME

SPAD

SSC

SSF

Human Factors Principle

Performance Shaping Factor

Route Hazard Checklist

Rail Safety and Standards Board

SPAD Hazard Checklist

Subject Matter Expert

Signal Passed at Danger

Signal Sighting Committee

Signal Sighting Framework

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CONTENTS

1. INTRODUCTION......................................................................................................... 1

1.1 BACKGROUND..................................................................................................................1

1.2 STAKEHOLDER CONSULTATION....................................................................................1

1.3 OBJECTIVES OF THIS REPORT......................................................................................1

2. THE SPAD RISK MANAGEMENT SUPPORT TOOL ................................................ 2

2.1 OVERVIEW ........................................................................................................................2

2.2 DESIGN ..............................................................................................................................2

3. THE HUMAN FACTORS SPAD HAZARD CHECKLIST............................................ 4

3.1 OVERVIEW ........................................................................................................................4

3.2 DESIGN ..............................................................................................................................4

3.3 FURTHER READING .........................................................................................................7

4. THE ROUTE HAZARD CHECKLIST.......................................................................... 8

4.1 OVERVIEW ........................................................................................................................8

4.2 DESIGN ..............................................................................................................................8

4.3 FURTHER READING .........................................................................................................9

5. THE SPAD MITIGATIONS DATABASE................................................................... 10

5.1 OVERVIEW ......................................................................................................................10

5.2 DESIGN ............................................................................................................................10

6. THE SIGNAL SIGHTING FRAMEWORK ................................................................. 12

6.1 OVERVIEW ......................................................................................................................12

6.2 DESIGN ............................................................................................................................12

6.3 FURTHER READING .......................................................................................................13

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1. INTRODUCTION

1.1 Background

1.1.1 Human Engineering Limited has undertaken numerous projects for the Rail Safety and

Standards Board, Network Rail and various Train and Freight Operating Companies in

recent years on identifying and mitigating the human factors risks associated with Signals

Passed at Danger (SPADs). These projects have culminated in the generation of several

tools to support the SPAD risk management process. These include:

• The Human Factors SPAD Hazard Checklist

• The Route Hazard Checklist

• The SPAD Mitigations Database

• The Signal Sighting Framework

1.1.2 They form part of a suite of tools, techniques and standards on SPAD risk management

available to the industry. However, there has, until now, been little guidance to indicate

how, when and by whom these tools should be used in the SPAD risk management

process. In addition, similar problems are addressed by more than one tool but with

differing degrees of success, and there was no indication of when one tool should be used

in preference to another.

1.1.3 There was therefore a requirement to produce a single, integrated process, which shows

what tools exist and at what stage of the risk management process they can be used. This

not only improves the usability and usefulness of the tools, but also greatly reduces the

workload of the user, and encourages a more consistent approach to SPAD management.

1.2 Stakeholder Consultation

1.2.1 Through widespread consultation with key stakeholders, involving Operations, Safety,

Signal Engineering staff and Standards specialists from Network Rail, RSSB, TOCs and

FOCs, a user friendly ‘SPAD Risk Management Support Tool’ has been developed. The

Support Tool provides practical guidance on what tools can be used to support various

SPAD risk management activities, and by whom. Hosted on the industry website

www.spadweb.com, the SPAD Risk Management Support Tool is easily accessible by

those responsible for SPAD risk management.

1.3 Objectives of This Report

1.3.1 This report provides an overview of the SPAD Risk Management Support Tool and of the

constituent tools that have been developed and recently updated by Human Engineering.

References to detailed reports about the development of each of the tools are provided,

where available.

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2. THE SPAD RISK MANAGEMENT SUPPORT TOOL

2.1 Overview

2.1.1 Developed by Human Engineering Limited on behalf of RSSB and Network Rail, the SPAD

Risk Management Support Tool is an interactive, web-based application that provides

information on the tools that are available to support various SPAD risk management

activities, from signal design and commissioning through to SPAD investigation and

mitigation. For the first time, details on these tools and standards are accessible from a

central location, reducing the workload of the user and encouraging a more consistent

approach to managing SPAD risk.

2.1.2 Guidance is provided on what each tool is designed for, who should use it, and when.

Information on relevant Railway Group Standards and Network Rail Company Standards

is also given. In most cases the Support Tool provides a direct link to the various tools or,

as in the case of some restricted access standards, a contact name for further information.

2.1.3 The SPAD Risk Management Support Tool is hosted on www.spadweb.com. It is hoped

that the Tool will be a valuable resource for anyone who contributes to SPAD risk

management, but it is likely to be particularly useful for those involved with signalling

scheme designs, SPAD investigations, and the management of safety-critical personnel.

2.2 Design

2.2.1 The SPAD Risk Management Support Tool is constructed around a roadmap of the

different stages of the SPAD risk management process, developed in consultation with

industry stakeholders (see Figure 1).

Figure 1: The SPAD Risk Management Roadmap

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2.2.2 The roadmap provides links to the wide variety of different tools that are used for SPAD

risk management, why they are used, how, and by whom. It also identifies relevant

Railway Group and Company Standards that should be taken into account. Any conflicts

or overlaps between the most widely used SPAD management tools have been taken into

account and guidance provided on the context in which each tool is best used.

2.2.3 The structure of the website allows the user to select the activity they are carrying out (e.g.

signalling scheme design, SPAD investigation), and then identify appropriate tools and

standards by selecting from further options or sub-activities.

2.2.4 The following information is provided about each tool:

• A description of the tool.

• Whether use of the tool is mandatory.

• Citation (whether the tool requires other tools / information in order to be used).

• Where the tool itself can be found.

• Relevant users of the tool / who the tool is applicable for.

• Whether training is required to use the tool.

• Restrictions on access to the tool.

• Contents of the tool and details of any overlap/conflict with other tools (by clicking

on the hyperlink).

• Where the user can obtain a copy of the tool when it is not possible to provide a

direct hyperlink.

2.2.5 The following information is provided about each Standard:

• An overview of the Standard.

• Whether use of the Standard is mandatory.

• Where the Standard can be found.

• To which roles the Standard is applicable.

• Restrictions on access to the Standard.

• Where the user can obtain a copy of the Standard when it is not possible to

provide a direct hyperlink.

2.2.6 The SPAD Risk Management Support Tool can be searched in three ways: either by

entering a known keyword from the tool or standard, by activity and sub-activity from the

dropdown menu, or entering the number of a Company or Group Standard, if known.

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3. THE HUMAN FACTORS SPAD HAZARD CHECKLIST

3.1 Overview

3.1.1 The Human Factors SPAD Hazard Checklist (SHC) was developed by Human Engineering

in conjunction with Network Rail and the Rail Safety and Standards Board. It enables a

systematic, objective and coherent approach to the investigation of Category A SPADs.

Its purpose is to identify all possible human factors causes of SPADs, including

infrastructure and underlying operational issues. It also provides a way of prioritising

which features of a signal location are generating the greatest SPAD risk and identifies

appropriate mitigation measures.

3.1.2 Originally developed in 2002 for use by Network Rail investigators as part of the formal

SPAD investigation process, the checklist and its associated guide to mitigation measures

have recently been fully updated and extended. It now provides additional guidance for

TOCs and FOCs on the generation of appropriate action plans for the management of

drivers who pass signals at danger in order to:

• Support best practice for the management of drivers following their involvement in

a SPAD incident.

• Minimise the risks of drivers having a second (or further) SPAD after having their

first one.

3.1.3 Although it has been designed with SPADs in mind, many of the human factors in the

checklist will be common to other types of incident (e.g., station overruns, failures to stop,

etc). It can also, therefore, be used to understand and manage the factors underlying

other safety of the line incidents.

3.1.4 The checklist is available in paper, Excel and web-based electronic formats, all of which

can be obtained via www.spadweb.com.

3.2 Design

3.2.1 The checklist follows a simple logic that is rooted in the sequential stages of driver

information processing. It is designed to address the human factors SPAD hazards that

may be encountered by the driver during the signal-reading task and is divided into the

following categories:

• A Personal factors

• B Attention/distraction factors

• C Visibility factors

• D Perceptibility factors

• E Association with line factors

• F Reading the aspect factors

• G Interpretation factors

• H Action/Performance failures

3.2.2 There are eighty two questions to answer in the checklist. Questions relate to the presence

or absence of hazards and have been worded to enable simple yes/no answers (see

Figure 1 for example).

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Figure 2: Example Checklist Questions

3.2.3 Guidance is provided for each question outlining the information required to answer the

question and the underlying evidence for its inclusion in the checklist (see Figure 3 for

example).

Figure 3: Example Checklist Guidance

3.2.4 Once all questions have been answered, findings can be automatically summarised at the

click of a button. Each item is rated on a three-point scale that indicates the severity of the

hazard, according to the subjective ratings of over 600 drivers who responded to a

questionnaire. A link to appropriate mitigation measures is provided (see Figure 4 for

example).

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Figure 4: Example Checklist Results

3.2.5 By addressing hazards weighted as high severity first, the selection and implementation of

mitigation measures can be prioritised. An example mitigation measure is shown in Figure

5.

Figure 5: Example Mitigation Measure

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3.3 Further Reading

RSSB, 2004. T313: Analysis of driver survey material about signal sighting. Examination

of the MRT Survey. Report by Human Engineering Limited for the Rail Safety and

Standards Board. HEL/RSSB/03996/RT1, Issue 1, 2004.

RSSB, 2005. T435: Developing signal sighting strategies for managing conflicting

requirements. User Guide for Human Factors SPAD Hazard Checklist. Report by Human

Engineering Limited for the Rail Safety and Standards Board. HEL/RSSB/041123/RTB2,

Issue 1, 2004.

RSSB, 2005. T435: Developing signal sighting strategies for managing conflicting

requirements. Overview of Signal Sighting and SPAD Risk Management. Report by

Human Engineering Limited for the Rail Safety and Standards Board.

HEL/RSSB/041123/RTB1, Issue 1, 2005.

Turner, C. Harrison, R. & Lowe, E., 2003. Development of a Human Factors SPAD

Hazard Checklist. Contemporary Ergonomics, 2003. Taylor and Francis. Document

available on the RSSB Human Factors Research Catalogue CD Rom.

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4. THE ROUTE HAZARD CHECKLIST

4.1 Overview

4.1.1 The Route Hazard Checklist (RHC) is a version of the Human Factors SPAD Hazard

Checklist that can be used proactively to address potential SPAD hazards on a route. By

assessing not only the number and type of hazards found on a route, but also route

features and their density, the RHC has an application in two forms of risk assessment:

• It allows TOCs to identify those elements that, from a human factors perspective,

contribute to risk; determine which routes are particularly difficult; and use this

information in training programmes. For example, increased emphasis could be

placed on those areas with the highest RHC score during route learning, and this

training could include reference to these specific hazards.

• It could also be used to extend the risk assessment procedure currently used for

signals. The current procedure scores existing and proposed track layouts, with

the aim of predicting the frequency of collisions and factoring the consequences

of these into the assessment of a proposed track design. This process currently

uses a list of questions to predict SPAD likelihood; the RHC would therefore

complement the process by providing a more sensitive means of SPAD

prediction.

4.2 Design

4.2.1 The hazards in the RHC are grouped into 7 categories:

• RHC1 Sources of distraction

• RHC2 Visibility factors

• RHC3 Perceptibility factors

• RHC4 Association with line factors

• RHC5 Reading the aspect factors

• RHC6 Interpretation factors

• RHC7 Transitory hazards

4.2.2 These items refer, primarily, to permanent features of the route. When performing a route

assessment, the user concentrates on these features to calculate an overall hazard score

and identify those signals where an error is most likely.

4.2.3 However, the RHC also contains a category describing transitory issues, for example

contractors working on the line and poor weather. While these are likely to change on a

day-to-day basis, they are also items that can be observed while driving and carry some

risk. They can therefore be used in a human factors assessment of risks on the route

during driver training. It is possible to look for evidence of a driver under assessment

being aware of any such hazards encountered, by, for example, driving a route and giving

a simultaneous route commentary. It is also possible that some routes will be more prone

to some of these transitory hazards than others. For example, routes through mountainous

areas may be more prone to fog than routes at a lower level, and this could therefore be

factored into the route hazard assessment.

4.2.4 Organised and used in exactly the same way as the SPAD Hazard Checklist, with links to

appropriate risk mitigation measures, the RHC is also available in paper and electronic

formats and is available via www.spadweb.com.

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4.3 Further Reading

RSSB, 2004. T313: Analysis of driver survey material about signal sighting. Examination

of the MRT Survey. Report by Human Engineering Limited for the Rail Safety and

Standards Board. HEL/RSSB/03996/RT1, Issue 1, 2004.

RSSB, 2005. T435: Developing signal sighting strategies for managing conflicting

requirements. Overview of Signal Sighting and SPAD Risk Management. Report by

Human Engineering Limited for the Rail Safety and Standards Board.

HEL/RSSB/041123/RTB1, Issue 1, 2005.

Turner, C. Harrison, R. & Lowe, E., 2003. Development of a Human Factors SPAD

Hazard Checklist. Contemporary Ergonomics, 2003. Taylor and Francis. Document

available on the RSSB Human Factors Research Catalogue CD Rom, 2005.

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5. THE SPAD MITIGATIONS DATABASE

5.1 Overview

5.1.1 The SPAD Mitigations Database has been produced to assist Network Rail, its contractors

and Train and Freight Operating Companies in managing those factors that can contribute

to SPADs. Designed to replace the current Anti-SPAD Toolkit (Network Rail, Issue 09,

2004), it contains the latest in SPAD risk management good practice measures, consistent

with those contained within other industry tools, checklists and guidance documents.

5.1.2 Mitigation measures within the database are comprehensive and include not only

infrastructure factors, but also many issues associated with Driver recruitment, selection,

training, assessment and monitoring. Human factors issues are incorporated and the

database links directly to the SPAD Hazard Checklist, should more prescriptive guidance

on mitigation measure selection be required.

5.2 Design

5.2.1 The database can be browsed as a general directory of information or can be interrogated

with specific search terms, based on key words, signal type, mitigation type, or SPAD

circumstances. Case studies and photographs are provided for each mitigation measure,

where appropriate.

Figure 6: Example Page from the Mitigations Database

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5.2.2 The database is intended to complement the application of the correct Railway Group

Standards and Network Rail Company Procedures, rather than to replace, over-rule or

modify their use. Users should not assume that a toolkit item authorises any derogation,

non-compliance or exemption from Railway Group Standard or Network Rail Company

Procedure.

5.2.3 Many of the measures contained within the database have the ability to control risk in

other scenarios. A platform over-shoot incident is regarded in many quarters to be a

SPAD without a red signal’ as many of the issues are the same. Consideration must be

given to the measures contained within the database for use in other scenarios where

there is some similarity in root cause.

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6. THE SIGNAL SIGHTING FRAMEWORK

6.1 Overview

6.1.1 To maximise signal visibility and readability, a number of factors in relation to the signal

location, operational needs and mandatory requirements have to be considered. These

requirements can lead to conflicting recommendations for the optimum signal sighting

arrangement. The expertise and professional judgement of Signal Sighting Committee

(SSC) members are crucial when resolving these conflicts. However, it is also necessary

to ensure that the chosen recommendations are effective and based on evidence.

6.1.2 The Human Factors Signal Sighting Framework has been developed to assist signal

designers and SSC members in resolving conflicts between signal sighting requirements.

It is a systematic tool that helps the user to:

• Identify any features at a planned signal location that may interfere with signal

sighting, e.g., curves, foliage, buildings etc (performance shaping factors).

• Select appropriate mitigation measures to overcome different combinations of

these features. The mitigation measures presented in the framework are proven

to be effective either through practical use or based on scientific evidence.

6.1.3 The framework is based on a series of principles for good signal sighting. These principles

represent the latest knowledge and understanding from research and best practice.

Although the framework was designed specifically for mainline colour light signals, it can

also be used effectively in the sighting of any other signals or signs.

6.1.4 The mitigation measures presented in the framework are suggested interventions that

have been proven to be effective either through practical use or based on scientific

evidence and are consistent with those in the SPAD Mitigations Database. The

application of appropriate mitigation measures should ensure that the good sighting

principle to which they are related can be achieved.

6.1.5 However, due to the complexity surrounding signal arrangements and the uniqueness of

some signal locations on the British railway, a mitigation measure that is effective at one

location may be ineffective at another. The expertise of the SSC members is therefore

crucial in deciding which mitigation measures are appropriate for the signal location under

consideration.

6.1.6 The Signal Sighting Framework forms the basis of the human factors content of Network

Rail’s signal sighting training course.

6.2 Design

6.2.1 The Signal Sighting Framework incorporates details of the rationale behind its

development and a user guide. The signal sighting principles (Human Factors Principles,

or HFPs) are presented in priority order according to subject matter experts’ (SMEs)

ratings and the results of an objective comparison of the features of multi-SPAD signals as

compared to signals with no SPAD history.

6.2.2 The chairperson of a Signal Sighting Committee is required to complete a performance

shaping factor (PSF) checklist to identify any route features that could prevent an HFP

from being achieved. This can be done with the aid of a signalling scheme plan prior to

the SSC site visit, or can be printed out and completed on site.

6.2.3 Depending on the combination of PSFs identified, appropriate risk mitigation measures are

automatically prioritised according to the HFP to which they relate and presented at the

click of a button. The introductory page of the Signal Sighting Framework can be seen in

Figure 7.

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Figure 7: The Signal Sighting Framework

6.3 Further Reading

RSSB, 2005. T435: Developing signal sighting strategies for managing conflicting

requirements. Interim Report on the Validation of Human Factors Signal Sighting

Principles. Report by Human Engineering Limited for the Rail Safety and Standards

Board. HEL/RSSB/041123/RTA01, Issue 01, 2005.

RSSB, 2005. T435: Developing signal sighting strategies for managing conflicting

requirements. Validation of the Mitigation Measures Contained within the Human Factors

Signal Sighting Framework. Report by Human Engineering Limited for the Rail Safety and

Standards Board. HEL/RSSB/041123/RTA02, Issue 01, 2005.

RSSB, 2005. T435: Developing signal sighting strategies for managing conflicting

requirements. Results of the Signal Sighting Framework Subject Matter Expert Workshops

and Production of the Revised Signal Sighting Framework. Report by Human Engineering

Limited for the Rail Safety and Standards Board. HEL/RSSB/041123/RTA03, Issue 1,

2005.

Stapley, N., Wisawayodhin, N. & Mills, A., 2003. Developing a Framework for Managing

Conflicting Requirements. Presented at the First European Conference on Rail Human

Factors, 13-15 October 2003. Conference proceedings published by Ashgate. Document

available on the RSSB Human Factors Research Catalogue CD Rom, 2005.

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