ERTMS Bridging the gap between technology and adoption: a Human Factors case study

Elaine Thompson, Mott MacDonald

Introduction

• Considerations of introducing European Rail Traffic Management System (ERTMS) / European Train Control System (ETCS) on UK network

• Retrofit to existing trains and implementation in new build

• Highlighted the key factors that needed to be considered for adoption

Challenges

• ERTMS/ETCS Driver Machine Interface options for future train cab design

• Requires the transition between European Train Control System (ETCS) and existing train cab systems (Class B) on routes

• Management of these interfaces in terms of cab fitment and driver support is a key issue

System Integration Challenges

ETCS DMI and Class

B integratio

n

System Reliability

Cab environmen

t

Display technology

Position & reach

Train protection &

safety

Aims of the study

• Three main issues relating to the fitment of ETCS Driver Machine Interface (DMI) in rolling stock;

– Design and level of integration of existing Class B systems within the train cab with the DMI

– Appropriate technology for the DMI screen that optimises the train cab environment and train driver performance

– Choice of DMI interface - touch screen or soft key

Approach

• 3 levels of integration considered:

– No Integration: AWS and TPWS indications and controls separate to the ETCS DMI

– Partial Integration: Speedometer, AWS and TPWS indications integrated, AWS acknowledge button separate

– Full Integration: Automatic Warning System (AWS) and Train Protection Warning System (TPWS) indications and controls, and speedometer fully integrated within the ETCS DMI.

Existing Cab Layout (Class 43)

Existing Class 43

Non-Integrated Solution

Class 43

Fully Integrated Solution

Class 43

Transition between ETCS and AWS/TPWS

AWS/ TPWS

ETCS AWS/ TPWS

Transition between ETCS and AWS/TPWS

• Factors to reduce potential for errors

– Provide clear visual indication of the engaged level of train protection

– Ensure adequate visibility of controls and indications in all lighting conditions

– Provide good feedback to the driver to confirm that control inputs have been successful

AWS/TPWS integration

• Partially integrated solution appears to offer most benefit – AWS acknowledge button separate– Consider ETCS acknowledge button also separate

• Cab fitment– Reduced clutter on the driver console

• Impact on performance– Reduced visual clutter in the cab means that attention

is focussed on the DMI, which provides visual confirmation of train control

DMI Interface – Touch Screen vs. Soft Keys

• Touch screen:

+ More flexible layout of information

+ Only ‘active buttons’ displayed, can reduce workload

- Likely to have higher reflectance value

Image Source: ERA_ERTMS_015560 ETCS Driver Machine Interface

• Soft Keys:

+ Lower screen reflectance value

+ Increased tactile feedback

- Larger DMI unit, less flexible layout

DMI Interface – Touch Screen vs. Soft Keys

Integrated display of AWS/TPWS

• Design of AWS/TPWS interface, considerations:

– Most recent ERA DMI standard allows more flexibility on screen design

– ‘Customisable’ or ‘Unified’ layout options

– Design of indications – retain AWS ‘sunflower’ or design a new indication

– Interaction with AWS acknowledge button – frequency of use

Latest developments for GB standards

• Work to update standards:– GK/RT8075 – AWS and TPWS Interface Requirements

• Cover touch screen and soft key options

– GK/RT0036 – Transitions between Signalling Systems

• Number and frequency of transitions

• Driver workload around transitions

• Understanding fully the impact and potential errors

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