Drive a mile in my seat: Signal design from a systems perspective

The Institution of Railway Signal Engineers Inc Australasian Section Incorporated

DRIVE A MILE IN MY SEAT: SIGNAL DESIGN FROM A SYSTEMS PERSPECTIVE Anjum Naweed BSc MSc PhD Central Queensland University

John Aitken BE MIRSE SMIEEE Aitken & Partners

SUMMARY Train drivers navigate conventionally designed railways using a keen awareness of their routes and by calculating likelihood predictions of future states. These processes have traditionally followed a model of signal-to-signal based running, which comprises the awareness of their static (location-based) and dynamic (aspect-related) properties. This paper reports findings from a study that examined the socio-cultural and technical ties between the signal and the driver in the context of SPAD risk management. It provides examples of how signal aspects are being interpreted on Australasian railways, how operational pressures are altering the driver-signal dynamic, and how the meaning of the caution aspect has evolved in today’s dynamic and productivity oriented rail environment. The paper seeks to describe the train drivers’ experience of interpreting and responding to railway signals, so that the signal engineering community may better understand the implications of introducing new variables and schemes into their signal design language.

1

INTRODUCTION

Train drivers have traditionally navigated conventionally designed railways by performing likelihood predictions of future signals and future train states [1]. These rely on a good level of situation awareness and knowledge of the track. Referred to as route knowledge this comprises static and dynamic aspects of memory. Thus, there is interplay between knowledge that encodes the location of the signal, knowledge that processes the position of the signal relative to the current location, and knowledge that predicts or estimates future signal aspects [2, 3]. These processes include a variety of individual and external factors, such as an accurate understanding of train handling characteristics, foundational rules, and so on [2]. The downside is the signal passed at danger event (SPAD), effectively describing instances where the train has exceeded its limits of authority. There are many reasons why SPADs happen. Forgoing the ‘technical’ causes (e.g. signal errors and reversals), issues with seeing and responding to signals can arise from sighting problems, poor rail conditions, and inattention. Less clear are the causes behind SPADs that result from signals being misread, misjudged, and from failures in human-systems interaction [4]. A plethora of human factors issues may play a part, but little is known about how train drivers actually cope and condition themselves to mitigate the problem. Understanding their own response may help reverse engineer the nature of the issues. Train driving is characterised by a need to sustain attention for tremendously long periods, which increases the drivers’ vulnerability to disturbances. The key point here is that the interplay between the driver and the signal become much less reliable. The aim of this paper is to describe the train drivers’ experience of interpreting and responding to railway signals, so that the engineering community may better understand the

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implications of introducing new variables and schemes into the design language of their signals.

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THE RAIL SYSTEM

A SPAD can happen with or without the knowledge of the driver and through an error of omission or commission. This gives rise to a variety of human factors issues. For example, a driver that is distracted by a pedestrian at a crossing may apply brakes later than intended and experience a SPAD through an error of omission. On the other hand, driving unwittingly through a stop signal when departing a yard would give rise to a SPAD through an error of commission, but it would be more ambiguous – why did the driver miss the signal? The worst kind of SPAD is where the driver sails straight past a stop signal having mistaken it for a proceed aspect. This is a very simplistic way of looking at a complex failure mode, but clearly reflects that for one reason or another the driver-signal dynamic has disconnected. 2.1

The Human Factors Perspective

For all of its technical complexity, a railway possesses a very simple truth; rolling stock can only move in the direction the railway provides. Thus, movement authority is communicated to train drivers in the form of an elegant multi-aspect design. Few collision avoidance domains can boast the same mechanics. However, whilst this design is one of the few ways to control train movements on conventional rail networks, they give way to the SPAD, which is invariably one of the single biggest failure modes possible in rail. Figure 1 decomposes the basic layers of the rail system and illustrates some of the dynamic relationships that exist between them. The layers are closely coupled, but the most basic coupling is the driver-train system. While the driver and the train are restricted to the confines of the railway, the dynamic interactions between the rail infrastructure and terrain create implications for control 25 July 2014

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and performance. The infrastructure also introduces issues that are dependent on other dynamic tasks performed by other functional groups such as Signallers, and the terrain has its own geographical constraints that define how the system is operated. Driving a train is contextually bound by the delivery of performance and services, and dependent on activities performed by other groups such as Train Controllers. Despite all of this, performance is strongly influenced and ultimately determined by the weather, which cannot be controlled. While Figure 1 offers a very basic multi-system analogy of the rail system, the sheer dynamism, complexity and lack of transparency in its various components present important features that need to be considered when trying to understand SPAD and when trying to develop and implement formal countermeasures.

Drive a Mile in My Seat: Signal Design from a Systems Perspective

driver-processing level. Some of these are set/reset devices like the Automatic Warning System (AWS), which forces the driver to acknowledge signal awareness at cautionary zones, while others supervise train movement and prompt remedial braking for excessive speeds (e.g. ERTMS). In principle, safety technology of this type also aims to address the latent human factor issues associated with operating in a sustained and heightened state of attention and vigilance. Rail can however be a very capricious environment to operate on, such that these countermeasures are not always reliable. From the system’s perspective, the environment can manifest in the form of a monotonous landscape with very few signals and little changes in information, or conversely, as a world of mixed traffic, high event rates and huge infrastructure densities [7]. Driving in both of these states create challenges for situational awareness, distraction and mental fatigue. Thus whilst forcedresponse type countermeasures may work to mitigate an element of risk, they can also exploit other human factors issues, such as automaticity and habituation. For this reason, understanding the nature of the SPAD means understanding the driver-signal dynamic and building an appreciation of the systems perspective.

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RAILWAY SIGNAL PHENOMENOLOGY

Research by the Cooperative Research Centre (CRC) for Rail Innovation looked beyond the confines of technology to the strategies that drivers adopt to manage the risk of a SPAD [8]. The aim of this research was to determine the factors that impact on SPAD risk by examining how drivers engaged with risk under different conditions. A mixed methods approach used various techniques to examine different scenarios, and a comprehensive analysis of these was used to develop a model of SPAD risk for subsequent quantification of error-producing conditions. When collecting data, the study asked drivers to: “describe their relationship with the signal,” that is, articulate how they understood and worked with the signals in their environment. This may seem an odd question to ask, but consider the driver’s experience.

Figure 1 – Rail from a human factors perspective. 2.2

Formal SPAD Countermeasures

Today, safety technology has been woven into the fabric of the railway to mitigate SPAD-risk. Some rail networks use safety systems, which are designed to stop a train if passes a danger signal, such the Train Protection & Warning System [5] but these methods only dampen the effect of a SPAD once it is performed, thus do not address the cause itself. Others include enforcement systems that aim to stop the train before its reaches the signal such as Automatic Train Protection [6], and while there are differences in the way these are designed, there are still a number of scenarios that could lead to SPAD outcomes (e.g. ATP application in low adhesion). Rail networks also use systems to mitigate risk at the

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A train driver performs their driving task day in and day out, on train tracks that snake endlessly before them, and on a route that they are required to know like the back of their hand. They are on their own for the most part and the one thing they engage with all day every day is rail signals – hundreds if not thousands of them. Each signal has an aspect telling you if it is safe to move, and each signal is used to inform your evolving awareness of the world, whether it is to sustain your knowledge of the route or to inform throttle and braking actions, or both. Signals have an important part to play in a train driver’s life, so it stands to reason that they will also have a unique relationship with them and understand the signal language in a way that others wouldn't. The question that sought to ask train drivers about their relationship with the signals was answered in very different ways. One group of answers were a testimonial that signals were, the “top priority” for driving, and represented the “ultimate collision avoidance system.” But drivers also described signals with differing degrees of personal intimacy. One kind of relationship was all about the sense of regard and high esteem that drivers 25 July 2014

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had for signals, with choice words like “respect,” and matter-of-fact statements like “it’s the most respected thing out there.” Another kind of relationship projected the effect on not adhering to signals on the driver, the passengers, and the system. Drivers considered the signal to represent their “life-line,” or their “passenger’s safety.” Some drivers also described the impact of their relationship on the broader context of their lives and the signal was described as “my livelihood,” and “my bread n’ butter.” Interestingly, signals were also personified. This is not altogether surprising, given how isolating driving trains can be. This personification occurred in the form of a direct driver-signal dynamic where the signal was described as “my colleague” and “my best friend.” Another type of relationship extended the reach of the signal to that of a “boundary” or a “brick wall,” seeing it as palpable field or barrier that they were unable to cross without proper navigation. Lastly, the relationship also went beyond personification into a space where the signal and its ruling were analogised as a creed where the signal was as “my religion,” and “God.” These perspectives reflected a unique railway signal phenomenology (i.e. the subjective experience of the signal) in the architecture of railways. Beyond the lights, LEDs, and colour aspects, the signal is many things and it can be and is construed to be many things. Thus, whilst the driver-signal dynamic is rule-based, it is invariably open to interpretation. From a systems perspective, these data revealed that signals were something to rely on, befriend, respect, trust, fear, and obey. The signal was all of these, but behind it was the reality of the SPAD and the notion that one day, a driver may accidentally make the wrong prediction, or somehow, violate the tenets of their relationship. 3.1

SPAD = Acute Stress Response

Train drivers are trained and conditioned to react to the stop signal as a danger aspect and recognise that going past it represents a serious mode of safe working failure. When talking to drivers about their SPAD experiences in the CRC project, they reported being “shocked” “shaken” and feeling their “heart race.” These reactions characterise an acute stress response (i.e. shock to a traumatic event) and the symptoms that are associated with it such as the release of noradrenaline, increased heart rate, constricted blood vessels, change in blood pressure, and so on. The physiological changes in an acute stress response are also accompanied by extreme emotional irregularity, including disbelief, fear, and panic anxiety. Given this, what does it mean for those that describe their relationship with a signal as a “religion?” And what happens to it after a SPAD? Does a driver who used to see signals as a “friend” go on to perhaps see them as a “brick wall?” Does someone who sees it as a top priority start seeing it predominantly as his or her livelihood? It is therefore quite important from the behavioural perspective to understand underlying causation along the systems spectrum before risk engagement can be understood and the nature of SPAD-mitigation can be explored.

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SIGNALS VS SERVICE DELIVERY

Driver distraction is frequently described as a leading cause in human error related SPADs and a mechanism IRSE Australasia Technical Meeting: Newcastle

Drive a Mile in My Seat: Signal Design from a Systems Perspective

that leads to a break in the driver-signal dynamic [9]. However, few rail operators tend to recognise factors that are fundamentally related to the task as being a contributor to “human error” producing conditions for SPADs. A good example of such a distraction is time and performance pressure. Under time and performance pressure, attention can be easily allocated to one aspect of the task and in the process, attracted away from another one of equal or greater concern. This is not altogether surprising. The nature of safety-performance regulation is actually quite paradoxical - conceptually, keeping time and driving safely is very conflicting, and it can be difficult for the train driver to define how they should distribute their attention to maintain these goals. The CRC SPADs project collected SPAD scenarios from train drivers operating in Australia and New Zealand and used them to identify key risk factors that significantly increased the likelihood of a SPAD event. These scenarios were simulated (in the mind of the drivers) and as a technique for data collection, rationalised under the assumption that assessing SPAD likelihood would be grounded within the same cognition used when driving a real train. Each driver created a scenario using whatever drawings conventions they liked and shared them with the others in a focus group. Even though the research did not actually set out to look for task-related distractions, almost all the drivers were saying the same things – distractions from task-related sources were the number one risk factor. The most common were time pressure, which features in 60% of collected scenarios, and station dwells, which were in 50% of scenarios. The consequence of distraction from these distractors increased risk likelihood, particularly when present with sighting restrictions, which actually featured in 80% of scenarios [10]. 4.1

Time Keeping and Time Pressure

What did drivers say of time keeping? “Well, that’s your job. As a train driver your job is to get the train in on time.” Keeping time was considered a goal directed activity but time-keeping pressure was experienced as a distraction. The drawing in Figure 2 shows an example scenario that was collected in the CRC SPAD project. The drawing shows a section of track with a train about to enter into a caution zone. The upcoming signal is set to stop and located on a blind corner. While this signal is restricted from view, the driver knows about its location from route knowledge. Based on the aspect of the immediate signal, they also know that it would be set to danger. The driver noted the following in the drawing: “Not reacted to caution signal due to conversation with train control. Focus on-quick turn around of train due to timetable running late. Loss of focus left no time to react to red signal.” In the scenario the driver experienced a “loss of focus” from a radio call as they entered the caution zone. Aside from the train, the track and the two signals, very little infrastructure has been added to the drawing. The duration of the conversation has been marked, together with a meticulously drawn vignette of the driver losing focus. Given the propensity for acquiring and maintaining route knowledge, there is no reason why a SPAD would occur from sighting restrictions alone. Thus, the main risk factor for a SPAD in this scenario is time pressure, which drives the decision error to answer a call under unsafe conditions, and as a consequence, renders route knowledge far less dependable. 25 July 2014

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Half of all SPAD scenarios collected involved blind corners, indicating the importance of route knowledge for overcoming sighting restrictions, but also how brittle multi-aspect signalling could be when navigating using traditional driving parameters. Indeed, some train drivers were reported to be extremely fastidious in their time keeping: “there are guys that really try to keep up time and…they will do anything to try and make up time. They will, you know, bend the boundaries…”

Drive a Mile in My Seat: Signal Design from a Systems Perspective

In this scenario, the driver closed the door and departed when other cues announced the train was ready to leave (e.g. station staff, bell, train guard) instead of departing at the signal’s authority. The gravity of the error is emphasised by a near flanking-collision with an express passenger train on the parallel line, and the proximity of rail level crossing. Additionally, the train stop mechanism, which would detect the false start and automatically trigger the brakes of the departing train, has been located near the crossover point, which would allow the train to build up to a much faster speeds. The key risk factor for the SPAD in Figure 3 is station dwelling, not in the sense of the slack that is built into timetables, but the ‘experience of staying longer at a station than deemed to be necessary.’ A station dwell gives rise to feelings, anxieties and perceptions of workload that transcend the confines of usual scenario pathway. Ordinarily, the driver would complete platform work (assisted by the Train Guard if present), and then depart when the signal is clear to proceed. In the scenario given, the driver misses the last step and departs without signal consultation. The inattentiveness is rooted in disengagement from driving, and distraction from the station dwell. Train drivers also indicated that time pressure, or alternatively, the motivation to avoid time pressure, played a part in premature departure. Station dwelling was described as an anxious state to be in – on the one hand, participants are relieved to not be driving, but also feel ill at ease from a compelling need to keep moving. 4.3

Figure 2 – A SPAD involving a combination of time pressure and sighting restrictions. 4.2

Station Dwells: Hurry Up and Wait

Over half of the scenarios featured SPADs on station platforms. The vast majority occurred upon departure and also involved time pressure: “drivers accelerate away from platforms, trying to maintain a schedule.” The drawing in Figure 3 depicts a mixed-traffic environment, and a train waiting to depart the platform. The driver noted the following on the drawing: “Suburban train sitting at back platform waiting to depart. Regional train approaching to run express through station. Station staff announces train ready to depart and ‘spark’ driver closes doors and departs it look at red signal and almost sideswipes express pass. Train stop was in advance of signal, allowing spark to reach a higher speed before stopping it just short of side on collision.”

Figure 3 – A SPAD in a mixed-traffic environment involving station dwelling and time pressure.

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Route Knowledge Dislocation

Many scenarios combined sighting restrictions with time pressure and station dwelling. The drawing in Figure 4 depicts the scenario of a train waiting to depart a station. In this scenario, the driver arrives on the caution signal, which means that their next signal is located on a blind corner (Signal B, obscured by a tree) and set to danger. The driver misreads signal ‘D’ as their own, which is set to a proceed aspect, departs the station at speed and has a SPAD. Originally, the driver who invented this scenario highlighted the tree as the main contributor to the SPAD, and proposed a strategy to “cut it down!” However, the other drivers in the focus group suggested the tree was not the issue, and the driver should know from route knowledge that the visible signal was not their own. Consequently, the driver added the following amendment: “Driver is distracted @ station, then once back in the cab sees D @ green and assumes he is looking @ B signal which has been cleared to green.” The temptation to misread the signal and power away from the station instead of pulling away at caution was also attributable to time pressure.

Figure 4 – A SPAD involving distraction from station dwelling, time pressure, and sighting restrictions.

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It is important to note that read errors to other signals do occur in real world situations, thus the physical contribution (i.e. the tree) should not be disregarded. However, the scenario shown in Figure 4 presents a good example of conditions where route knowledge was less reliable and attention was diverted to a task that was far less safety critical. In this scenario, the experience of distraction projecting from both time pressure and station dwelling separated the driver from their route knowledge and safe working. Thus, the dynamics of time keeping and station dwelling impacted the ability to navigate the railway, particularly, under the conditions where sighting was restricted. In the brief error producing conditions presented, it is clear that distraction during train driving can happen from a number of sources related to the task, and the SPAD likelihood converges from a number of contemporaneous risk factors. Figure 5 draws on risk modelling conventions to conceptual representation how these risks converge [11].

Drive a Mile in My Seat: Signal Design from a Systems Perspective

journeys demonstrate this. Equally, there is ample evidence that on a significant number of occasions the assumption is invalid and results in a SPAD (or worse). SPAD data can advise situations where the driver has not observed or responded to a signal set to danger. However, knowing exactly how many situations in which the driver has not observed or responded to a clear signal is impossible to ascertain. This paper has considered the conflicting demands on the driver, the pressures of time keeping, and the interplay with (and application of) route knowledge to ensure that the signal is seen and clearly understood. But it is important to appreciate the cognitive demands and task loading associated with multi-aspect signalling on conventional railways. Having seen the signal the driver has to remember its aspect. In situations of doubt, the opportunity to refer to a signal has passed by and may easily gives rise to states of conflict in decision making e.g., having to choose caution and slow down, compromising the time keeping goal, or to hope all is well and risk a SPAD. The technology to overcome problems of perception, route knowledge and memory has long existed. Automatic Train Protection systems, if well designed, can provide the driver with added reassurance as a target speed is continuously displayed in the cab and enforcement of the authority is provided to ensure that the train will stop before the signal at danger, rather than after it (train stop) or not at all.

Figure 5 – Conceptual representation of how time keeping, station dwelling and sighting restrictions give rise to error and elevate SPAD likelihood [11].

5

SIX SECONDS (-20%) TO SEE OR SPAD

The signalling designer works to a very structured format. From the track plan the designer identifies the places where separation must be maintained: the points of conflict between converging or oncoming movements. Then the designer’s thoughts turn to headway: where do signals need to be placed to provide separation between trains? The headway, line speed, and braking patterns determine the signal spacing but signal placement is further restricted by sight lines. Considerable care is taken in reviewing the proposed locations of signals, with contributions invariably sought from experienced drivers, maintainers and operators. However, this is done in anticipation, usually in daylight, rarely in inclement weather. In signalling standards and guidance documents, the criteria to those who design the system is to maximise the visibility of signals, based on the train driver having a minimum of 6 seconds to read the signal [12]. This time may be reduced by short interruptions for up to 20% of the sighting time, except in the last 50 metres before the signal – the last second at 100 km/h. There is ample evidence to indicate that this is normally enough time for the driver to read the signal and respond. Many years of operation and millions of IRSE Australasia Technical Meeting: Newcastle

Howker [13] discusses the vast difference in route knowledge and experience that has resulted from changes in railway technology and organisation over the last fifty years. Despite this, the reliance of the entire signalling system on the driver’s route knowledge has scarcely changed from that discussed in the 1914 Proceedings of the Institution [14, p.87]. Signalling designers must comply with the design criteria stated in signalling standards; that much is clear. However, the standards prescribe an implementation procedure based on an assumption of complete route knowledge. The research presented in this paper challenges the validity of this assumption for today’s railways. Holding the view that rail operations would be okay if the driver did what they were ‘supposed to do,’ is a narrow perspective and rather simplistic view of the train-driving task. Instead, it is far more useful to ask why, that is, why is it that they are not doing what they are supposed to? Indeed, it may even be useful to ask what they are supposed to do? Is it to drive safely, or to keep time, or a combination of both? Most would agree that it is the latter, in which case one must recognise that there is a great deal of complex decision making involved in making it happen, and this may not be entirely appreciated unless the architects of the signals drive a mile in the seat of the train driver. There is yet an extra mile to travel. To appreciate what the train driver sees is enlightening. To synthesise that knowledge with the driver’s decision making processes, with traffic patterns, with train operation and systematic distractions demands new skills; skills which are simply not taught to signal designers today.

6

AN ABUNDANCE OF CAUTION

Most rail networks tend to assign the blame for humanerror related SPADS squarely onto the shoulders of the 25 July 2014

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driver. This may be appropriate for certain scenarios (e.g. SPAD caused by distraction from personal mobile phone) but less so for others. Some types of SPAD simply escape single factor and ostensibly judgemental accounts of failure. Contributing factors associated with organisational and procedural risk factors form part of the regulatory viewpoint [15]. The complexity in the domain is not always apparent, and some consideration needs to be given to the way certain layers of the system interact with one another. For example, consider the infrastructure and goal layers of the rail system (Figure 1). In the CRC SPAD project, the consensus was that drivers were seeing far more caution signal aspects than they used to in every day operations and the popular perception was that the caution signal was being devalued [16]. Clearly, an abundance of caution signals will have a detrimental impact on the stopping pattern. It is easy to theorise that at some point, driving against caution signals in a manner that treated them like a clear aspect became a norm with drivers essentially desensitising to the traditional meaning of the caution. It is also easy to surmise that the expectation of keeping time in spite of so many caution signals transferred to the operator, and ultimately, became a part of the rail zeitgeist. This concept is referred to in many ways, either as a normalisation of deviancy, risk blindness, or drift [17] and is becoming a more and more important issue for complex systems such as rail. The account of the rail system given in this paper, and the stories provided by the train drivers reflect the importance of this concept. Today, many rail signals are used to communicate more than just movement authority to the driver. They are ecological interfaces designed to inform both movement authority and advise speeds through various modes (e.g. colour, arrangement, steady/flashing states). The rhetoric of signal design has had to make way for operational demands and in the process, consideration for the impact that different variables and schemes will have on the psychology of collision avoidance has not had the attention that it deserves.

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CONCLUSION

This paper has broadly described the rail system, as it exists from a human factors perspective, and related the train drivers’ experience of interpreting and responding to signals. The intention is for the signal engineering community to better understand (and appreciate) the complexity of the train driving task, and the implications of introducing new variables and schemes into the signal design rhetoric.

Drive a Mile in My Seat: Signal Design from a Systems Perspective

[2]

A. Naweed, "Investigations into the skills of modern and traditional train driving," Applied Ergonomics, vol. 45, pp. 462-470, 2013.

[3]

N. A. Stanton and G. H. Walker, "Exploring the psychological factors involved in the Ladbroke Grove rail accident," Accident Analysis & Prevention, vol. 43, pp. 1117-1127, 2011.

[4]

J. Aitken, "Communication in emergency: Success or failure?," presented at the IRSE Australasia AGM & Technical Meeting, Adelaide, 2013.

[5]

D. Fenner, "Train protection," IEE Review, vol. 48, pp. 29-33, 2002.

[6]

W. Haifeng, L. Shuo, and G. Chunhai, "Study on model-based safety verification of Automatic Train Protection system," in Computational Intelligence and Industrial Applications, 2009. PACIIA 2009. Asia-Pacific Conference on, 2009, pp. 467-470.

[7]

A. Naweed and G. Balakrishnan, "Understanding the visual skills and strategies of train drivers in the urban rail environment," WORK: A Journal of Prevention, Assessment & Rehabilitation, vol. 47, pp. 339-352, 2014.

[8]

CRC for Rail Innovation, "Managing and mitigating SPAD-risk," Author, Brisbane: AU 2014.

[9]

G. D. Edkins and C. M. Pollock, "The influence of sustained attention on railway accidents," Accident Analysis & Prevention, vol. 29, pp. 533-539, 1997.

[10]

A. Naweed, "Psychological factors for driver distraction and inattention in the Australian and New Zealand rail industry," Accident Analysis & Prevention, vol. 60, pp. 193-204, 2013.

[11]

A. Naweed, "Hurry up and wait: Danger signals in the rail environment," Ergonomics Australia, vol. 3, pp. 1 - 6, 2013.

[12]

ARTC, "Signals," in Engineering (Signalling) Standard SDS01, Version 2.0, ed, August, 2006.

[13]

A. Howker, "Have we forgotten the driver? The Sequel," in Proceedings of the IRSE, 2007-2007, pp. 30-43.

[14]

IRSE, "Proceedings: Session, 1914 Annual Report," Manchester1914.

[15]

T. Simes, "SPAD Mitigation - A Regulatory View," presented at the IRSE Technical Convention, Adelaide, AU, 2004.

[16]

A. Naweed and C. Dance, "Are you fit to continue? Managng rail on the edge of safety and performance," presented at the 27th Australia & New Zealand Academy of Management Conference, Hobart, AU, 2013.

[17]

S. Dekker, Drift into failure: From hunting broken components to understanding complex systems. Surrey, London: Ashgate, 2014.

Acknowledgements The author is grateful to the CRC for Rail innovation (established and supported under the Australian Government's Cooperative Research Centres program) for funding this research. This paper reports results from Project No. R2.116 ‘SPAD risk Management and Mitigation.’

REFERENCES [1]

P. Branton, "Investigations into the skills of train-driving," Ergonomics, vol. 22, pp. 155-164, 1979.

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Drive a Mile in My Seat: Signal Design from a Systems Perspective

AUTHORS

Anjum Naweed

John Aitken

Anjum Naweed is a Senior Research Fellow at the Appleton Institute for Behavioural Sciences, Central Queensland University’s Adelaide-based campus. He was also the Deputy Program Leader with the Australian CRC for Rail Innovation (2011-2014) and led a number of their research projects.

John Aitken is an experienced communications engineer with a strong broadcasting, EMC and railway communications background. He has been involved in many of the Australian railway radio communication systems.

Anjum is co-chair of the transport special interest group (TranSIG) at the Human Factors and Ergonomics Society of Australia and a member of the Human Dimensions in Simulation division of Simulation Australia. He has contributed to the development of a number of industry guidelines, including the RSSB Engineering Good Practice Guide for the design of alarms and alerts, and the RISSB SPAD Risk Management Guideline. Anjum’s research has investigated the area of safety and security on topics involving train driver psychology, complex decision-making, knowledge representation, enhanced display design, level crossing design, and driver-cab ergonomics. His SPADs research has received several awards, and recently, he was awarded an ARC-linkage grant to explore new approaches for train driver training through augmented reality. Anjum has experience with a wide range of research techniques and is passionate about exploring all aspects of human factors, workplace culture, and the relationship between humans and machines.

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John is active in the railway industry and has been chairman of the Institution of Railway Signal Engineers, Australasia and a director and member of the Council of the UK based IRSE. He is the principal author of the railway telecommunications course within the Graduate Diploma in Railway Signalling and Telecommunications. John is the tutor for that subject and has formal training qualifications (Certificate IV in Training and Assessment). John’s interests in electromagnetic compatibility and system engineering for railways have given him a holistic approach to railway communications requirements. This interest has developed from a study of railway accidents in which communications (or the lack of communication) has played a part. He has written a number of papers on this subject. John Aitken is currently practising primarily in the field of electromagnetic compatibility in the rail environment. He has experience in locomotive and wagon compliance testing and certification for signalling and telecommunications systems as well as EMC compliance. John provides compliance certification, design and process test, audit and verification.

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