There’s a level in Tomb Raider III where Lara Croft must traverse the London Underground, through an abandoned tube station, and locate the secret lair of a mysterious brotherhood. It’s a right pain, full of cracking tiles, flame traps, and yes, being incredibly careful to ‘mind the gap.’ But as I meet with the team at DB ESG in the video game heroine’s hometown of Derby, UK, I quickly learn how getting additive manufacturing (AM) into the rail industry is perhaps an equally challenging mission.
“The rail industry tends to be cautious about adopting new technology,” says Daniel Hartley, Digital Manufacturing Business Lead for DB ESG, telling a familiar story of a traditional sector with a natural hesitance to break away from established practices, while adhering to stringent regulations.
And yet, against that backdrop, the rolling stock provider and engineering consultancy is deploying 3D printing and 3D scanning technologies, both in-house and outsourced, to address numerous rail supply chain and engineering challenges, specialising in large-scale technical integration projects.
“To really simplify that,” Hartley said, “we put stuff on trains.”
It was a customer request in 2018 to explore 3D printing for part obsolescence that inspired DB ESG’s own digital manufacturing journey. As Nathan Russell, Digital Manufacturing Team Lead tells TCT, the team started with a simple list of five parts and components, nothing too adventurous, but parts they believed could be a good fit for printing. They did some redesigning and testing before settling on two components – an arm rest and a seat back handhold – printed using FDM in Stratasys Ultem 9085 black material and finished in a rail-approved coating. The project took just three weeks, and while more expensive, it was a significant improvement on the original project costs which would have required a minimum order of 10 units and a lead time of four months. By 2019, DB ESG became the first provider in the UK to place 3D printed parts into commercial service on a passenger train. Those parts are still in service on those vehicles today.
The rail industry is uniquely challenged by part obsolescence. According to the Office of Rail and Road statistics, the average age of rolling stock for all passenger train operators as of March last year was 16.7 years, but they can run much longer before being retired. Much of British Rail legacy vehicles are made up of cast aluminium parts made by someone, somewhere, now long retired, and the impact of privatisation also means that manufacturers of many of those earlier vehicles simply don’t exist anymore or designs have been lost.
“One very common challenge is the design has been changed, but nobody's recorded that change,” Hartley explained. “We have a unique problem there that is quite specific to rail. When you scale this up across the many different variations of the ‘same’ vehicle, with their different owners and operators, all uniquely changed over decades, then factor in the more common supply issues like minimum quantities and long lead times, that’s where 3D printing, for us, became quite cost-effective.”
DB ESG
3D printed funnel for power unit
In 2022, DB ESG established a sub team committed to its digital manufacturing services, and has since supported over 100 individual projects for 20 different customers. It has also tested a host of different AM processes and materials including polymer selective laser sintering, stereolithography, and, more recently, metals. DB ESG is not tied to any single manufacturer or materials company, and it works with suppliers to direct the right technology to each unique problem. Sometimes, that might not mean additive at all.
“We don’t 3D print just for the sake of it,” Hartley affirms, “we still do welded fabrications, or use CNC machines – we use whatever production method is right for the specific use case.”
DB ESG is not trying to be a printing service provider; it wants its customers across the rail industry to learn about these technologies. The company regularly hosts drop-in lunches at train depots to give engineers opportunities to get hands on with parts and 3D scanners, and they typically leave with ample suggestions for potential challenges for which 3D technologies might hold the answer: part redesigns for reliability and performance, bespoke manufacturing aids, or even completely new designs. In one example, a customer needed a more streamlined way to clean dust from a vehicle’s power unit. Previously, this required removing the power unit, taking it away from the vehicle, and blowing air through it. Instead, the team printed a large funnel which can be hooked onto the vehicle in-situ and connected to the fans to blow dust away, turning a six-hour process into a half-hour job. In another, much smaller example, a simple bung used to cap an open tube on a seat design that was prone to popping out was redesigned so that it could be glued in. To a passenger, it’s “a nothing part” as Russell explained but it saved the customer “a real problem and hassle, and a lot of time and cost that they didn't need to have.”
3D scanning has also proven a useful third prong of its digital manufacturing business, not only for digitising parts, but to measure accuracy and investigate failures. DB ESG was recently tasked by a customer with scanning the fuel tanks of several different vehicle classes to alleviate concerns around structural integrity. The scans, compared against a model created from the original drawings, provided such a high level of detail that they were able to produce a full structural report containing indicators of distortion, weld-failure and even failed internal baffles.
DB ESG
3D scanners are used to digitise components
‘Trust’ is a word that permeates the conversation as we tour around DB ESG’s offices and 3D print lab, which features a pair of 3D scanners alongside two FDM printers, one desktop, another large-format. A third has been added since TCT visited. That means trust in the technology, using the right process to avoid disillusionment, and trust from the customer and end-user, to ensure their buy in.
“We have a lot of people in the industry that have done the exact same thing and used the same supplier for a long time,” Hartley explained. “You're not only asking them to move away from that trusted supplier relationship that they’ve held for many years but you're also asking them to do it with a technology that they're not familiar with, in a safety critical industry.
“Every single customer we've had has come back to us for another project. It is a trust thing. It's a new and novel technology. We have an industry that's kind of reluctant to new things. Nobody wants to be the first to do something because the first comes with risk.”
But 3D printing can also be used as a tool to reduce risk. Across the way from the 3D print lab is a prime example, where the team has built a full-scale 3D printed mock-up of a new train cab desk. It’s wired in with functional lights and buttons to feel like the real thing and allow drivers to familiarise themselves with a new layout before going into production.
“They're involved right from the start. Does this layout work for you? Is everything in the right position?” says Hartley. “It's probably an expensive thing to do to just produce one desk using a traditional method. With 3D printing, we can do that very quickly, relatively cheaply and if something has to change, we can change it very quickly.”
DB ESG
Inside DB ESG's Derby-based lab
Compared to sectors like aerospace and automotive, the rail industry has taken more time to embrace AM. While those industries come with their own standards and regulations, which AM suppliers have historically focused efforts on, rail has its own unique set of requirements. Parts must meet specific rail fire compliance standards, which don’t easily translate from existing fire-compliant products on the market. Today, more focus has been put onto specific solutions that match the UK rail industry standard EN45545-2, and DB ESG is also part of the Mobility Goes Additive network which sees several European rail companies working alongside AM technology providers to ensure standards are met.
The DB ESG print lab is filled with examples of where AM has proven effective: in a re-engineered cab handset for a London Underground train, which was 3D scanned and redesigned to remove common failure points, or the large power brake controller cover, which was printed in ULTEM 9085 and found to be a suitable replacement. The team never knows what kind of challenge will come through the door, whether it's a train door opening on the wrong side, or a solution for tactile signage, but it has spent the last six years building its capabilities as a rolling stock digital manufacturer to ensure it has a solution.
"We've done lots of R&D to get our printers to a point where they can make parts that are acceptable for in-service use,” Russell said. “Being a rail consultancy, we know all the standards, we know what to do to get stuff approved on the vehicle. And we can also make those parts as well.”
This article originally appeared inside TCT Europe Edition Vol. 32 Issue 5 and TCT North American Edition Vol. 10 Issue 5. Subscribe here to receive your FREE print copy of TCT Magazine, delivered to your door six times a year.
