Technical Interview

Rail sleuths: The investigative edge of rail forensic technical services

“By and large, the largest construction projects presently underway are rail infrastructure. Numerous large rail projects are going on in the UK, Europe, and worldwide in fact. Many of them are incredibly complex, and having to adopt legacy systems… Inevitably, there are going to be complications with all of this,” states Dr. Nigel Bish.

HKA offers forensic technical experts who serve as witnesses and advisors for disputes and distressed projects around the globe. Forensic technical services are “the mainstay of our global work, and we have many disciplines that we cover, representing pretty much the whole spectrum of the construction industry,” says Dr. Bish. When it comes to the cases Dr. Bish and his team are called to investigate, “causation is not always that apparent and may involve multiple parties,” he explains. Additionally, a single investigation “can involve multiple issues of conflict depending on the complexity of the projects.”

“The majority of our instructions we receive from legal counsel, and they will be representing a client which can be any customer from a joint venture for a very large rail project. A rail operator, a supplier… There are a host of different variations depending on what the dispute is based on, whether it’s based on infrastructure, rolling stock, power and control systems, any or all of these, and so on. We can represent either side within these disputes,” details Dr. Bish.

Railway Switch at harbor in Linz, Austria

The creation of a standalone rail forensic technical services was a response to a need, Dr. Bish explains. “Initially, we had it hidden within our infrastructure department, but because we were getting so many inquiries, we brought it out as a standalone department two years ago, which I am very proud to head,” says Dr. Bish.

The department is today composed of 500 experts and covers most areas of engineering and construction. “Not all of our experts were originally from a rail-specific background, as rail is a multi-disciplinary entity,” says Dr. Bish. As such, “there is still considerable overlap” with other departments since “rail, unlike many other projects, touches upon the subject matter from every other of our departments,” he explains.

Indeed, rail projects overlap with civil, structural, and geotechnical aspects concerning bridges, viaducts, and permanent way issues. Similarly, projects can require electrical expertise in power, control, electrification, and signalling issues, extending to mechanical expertise covering rolling stock and rail infrastructure disputes. As such, “I often have to pool in from my other departments and disciplines, experts in specific areas that can assist with some of the ongoing disputes,” shares Dr. Bish.

“Rail, as we know, is no exception to change, and to remain at the forefront of what we do as experts, our multidisciplinary experts constantly adapt,” adds Dr. Bish. “We never stop learning – the ethos we often apply is that we learn from other people’s mistakes. Equally, we are continuously developing and expanding our fields of expertise, to keep ahead of demand and the changing world of construction. This is particularly true in rail, which is presently receiving substantial investment worldwide,” he continues.

Aerial view of train tracks entering London Bridge in London, where HKA has its head offices.
(Photo: Shutterstock)

When investigating a case, the Rail Forensic Technical Services team generally begins by gathering as much information as possible regarding the dispute. The majority of disputes brought to HKA for investigation have to do with failures in a design: “Something hasn’t quite been delivered, the client has not received what they wanted. Whether that is a misinterpretation on both sides or either side… We have to look into that,” explains Dr. Bish.

This research involves “Any documentation touching upon what was originally required and what the result was, and everything in between. Manuals, design documentation, instructions and agreed deliverables, invitations to tender, what was required by and given to the client, anything that was possibly overlooked… Those, we look at,” enumerates Dr. Bish.

Beyond examining the information in front of them, the team also needs to critically assess the information that is not there. Indeed, “It happens that clients forget to turn over information, like drawing revisions for example. We have to work around it as best we can. We can do our best to assess if the data is incomplete or not. Thankfully it’s not too common,” he adds.

Gathering information, however, is just one first step in a complex process that differs significantly from case to case. Nigel Dr. Bish shares insight from a few of his stand-out cases to give further insight into the investigative process.

Gathering information for an investigation is a is a time-consuming process.
(Photo: Shutterstock)

A more humorous solution related to a botched delivery of two large walk-in transformer rectifier units (TRUs), delivered to two different sites by rail. Much publicity surrounded this event, “however much to the embarrassment of the project manager, it appeared that the bespoke designed units were incorrect and that a large part of the switchgear was missing in one of the units,” says Dr. Bish. This case came down to the A4 sheets of paper on which the delivery notes were written being switched accidentally for each TRU. “Apparently, the delivery note had been placed on the inside of the door in case it blew off before delivery. Probably the easiest resolve too – for us at least,” shares Dr. Bish.

Not all cases, however, are as quick to solve. Dr. Bish recounts one of his most complex cases, a significant multi-rail infrastructure project involving numerous experts. Various technical challenges were not adequately addressed during the initial tender stage. Specifically, the impact of the local climate, with extreme cold in winter and heat in summer, was not taken into account in the design which led to issues.

As such, the client asked for the contractor to be investigated, because the rail system that was delivered was not functional as promised. “All too often, projects tend to evolve, and this was no exception. It’s a question of what constitutes developed design and what should have been considered at the concept and preliminary stages during the bidding stage, compared to a scope change and therefore a variation in the client’s instruction,” he states.

Lastly, Dr. Bish considers his ‘deadliest case’: the investigation of a Medium Voltage (MV) GIS switchboard that had operated while maintenance staff were in attendance. “Unbeknown to the technicians at the time, it had low pressure and would not withstand a resulting arc if it operated. Unfortunately, it untimely tripped in their presence under fault condition, whereupon the switching chamber exploded, and a fireball engulfed the panel, injuring the maintenance staff,” described Dr. Bish. “Whilst I was informed the injuries sustained were not serious, the consequences of such an incident could have been far worse.”

Extreme weather, which must be taken into account when building rail infrastructure, is becoming increasingly common globally. (Photo: Shutterstock)

Dr. Bish described his most creative solution as being one from a few years ago, involving the analysis of a rail interrupter, specifically an MV switch, for which there were “no documents, no suppliers’ details (because the manufacturer had ceased trading), and no way of internally assessing the switch.” Indeed, the switch contained sulphur hexafluoride (SF6) insulating gas. “We couldn’t just open it up because there are regulations about sulphur hexafluoride,” explains Dr. Bish, “so we had to send it off to an approved contractor who drains it. And it was only then, after it had been cleansed and degassed that we could actually open it up and have a look.”

To work around this, Dr. Bish had it X-rayed, “something I’ve never had to do before, and that was just really interesting to see what was inside it.” This led to Dr. Bish finding “a whole host of failures.” A lot of it was purely due to wear and UV degradation. It had caused some very minor fissures, some very small fractures. And then it had lost some of its internal gas pressure.” This was found to be the cause of the failure: “a combination of mechanical linkage failure, small fractures within the polymeric housing (UV & Mechanical fatigue), with subsequent loss of gas pressure.”

To Dr. Bish, “identifying the failure was both complex and costly – due to the X-rays and degassing – but nonetheless an enjoyable challenge to investigate.” The investigation led to new maintenance protocols being implemented, based on Dr. Bish’s findings, “to identify any near end of life switches to avoid any further failures”, as “the asset manager feared that many of the remaining units would suffer the same fate.” Dr. Bish emphasises the need for caution in distinguishing between providing forensic advice and providing design suggestions. In this instance, however, a health and safety warning was later issued based on Dr. Bish’s findings.

X-ray of the switch (Photo: Dr. Nigel Bish, HKA)

Data and data analysis are essential components of each investigation. However, to Dr. Bish, “the best tool that we have is the wisdom and experience of my colleagues.” Indeed, one “can use a whole host of technology, such as monitoring equipment, but we still need to understand what the data represents, and a lot of the equipment will not do that for you.” To Dr. Bish, “That purely comes from the experience of the trained user, the engineer, or the engineering consultant.” He stresses that “We ourselves have to do that to deduce what the issue is. That’s something that you can’t get from a box of gizmos. Interpreting what the technology is telling you, is really the best asset we have.”

For this reason, the application of artificial intelligence (AI) in forensic analysis remains limited. Dr. Bish, who utilised AI during his doctoral research on partial discharge in high-voltage cables, acknowledges the prevalence of AI in condition monitoring, citing its extensive use in the industry. “Having attended the IRS last year, there are a lot of condition monitoring presentations, and AI use and application are rife within that area. That’s going to continue, I should imagine,” Dr. Bish commented. However, when it comes to forensic work, Dr. Bish affirms: “I’m pleased to say no, we don’t use AI modelling in our forensic work,” he stated. “Our expert opinion is based on our observations, our expertise, and our experience.”

Looking forward, Dr. Bish considers that there is “increased reliance on software-based systems” and ultimately the use of AI will further roll out in many areas, rail being no exception. “We are already familiar with the readers at ticket gates and ticketing machines failing, which at best is frustrating. Increasingly we will be at the mercy of source code failures, which all too often fail indiscriminately. Identifying software and intelligent systems of the future and their application will mark an extending generation of forensic technical services and is already an area that we (HKA) are additionally working in,” he says.

Data (Photo: Shutterstock)

In addressing engineering failures, attributing causation solely to human error may seem convenient, yet Dr. Bish points out a more nuanced reality, stating “It would be all too easy to cite human error as causation, and in many cases poor foresight is a contributory or major factor.” While human oversight can indeed contribute, unpredictable equipment malfunctions and unforeseen environmental factors also play significant roles.

Dr. Bish further emphasises the need for a broader perspective when assessing failures, citing the interplay between human oversight, environmental changes, and material factors: “Whilst we could assume that poor record keeping or lost details may be attributed to human error, on occasion there are other influences, such as water table fluctuation and the erosion of unconsolidated materials causing sinkholes, that could not easily be foreseen.” These factors underscore the complexity of engineering challenges and the necessity for comprehensive risk assessment.

Reflecting on these dynamics, Dr. Bish advocates for a holistic approach to engineering analysis that integrates human error alongside environmental and material considerations. By acknowledging the multifaceted nature of engineering failures, professionals can better navigate the evolving challenges posed by climate change and unforeseen environmental impacts. “Most people tend to ask: is it human error or something else? I tend to find that actually it is a combination of those, and increasingly, now, we have to consider climate as well. So perhaps there is a bit of human error in that – not taking into account planetary condition changes, and material changes as well,” he concludes.

Flooded parking facility for trains in Norway after heavy rain on the night of 27 August 2023. Extreme weather is becoming increasingly common globally and poses risks to rail infrastructure. (Photo: Bane NOR)

Dr. Bish expects increased demand for forensic rail services, as the number of rail infrastructure projects continues to increase, with timelines stretching far into the future. “There are so many different projects going on, announcements of investments in renewals or new infrastructure, globally. That’s going to continue for a while. There was always the aim and the desire for a modal shift to rail, and that has been advancing. This expansion is going to continue for the foreseeable future at least,” stresses Dr. Bish

To Dr. Bish, this expansion, “combined with a shortage of experienced personnel within engineering, I think this sets the tone for the future.” Indeed, rail infrastructure is ageing worldwide. “There is a lot of legacy equipment out there, and much is well overdue for replacement. We need to combine new systems with expertise that is now retiring, with no one to replace them. It’s going to get busier,” he concludes. He also emphasises the need to attract younger talent to engineering, particularly in heavy industries, as experienced engineers retire without sufficient replacements, posing a growing concern for the future of these crucial sectors.

This publication presents the views, thoughts or opinions of the author and not necessarily those of HKA. Whilst we take every care to ensure the accuracy of this information at the time of publication, the content is not intended to deal with all aspects of the subject referred to, should not be relied upon and does not constitute advice of any kind. This publication is protected by copyright © 2024 HKA Global Ltd.


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