Suddenly, interest in regulatory regimes for the rail industry appears poised to increase exponentially. Of course, this is owing to the unusual level of mass media attention that has fallen on the derailment of a toxic chemical train shipment in Ohio: an admittedly alarming, albeit somewhat common occurrence.
Uniquely, this is one area where the existing applications of additive manufacturing (AM) to transportation are already positioned primarily to address safety. Largely responsible for that is the trade organization Mobility goes Additive (MGA), a Germany-based, international network of companies, which focuses mainly on the use of AM for the rail industry, though its affiliate group, Medical goes Additive is directed at healthcare.
3D printed turbine wheel for a steam locomotive. Image courtesy of Deutsche Bahn
The managing director of MGA is Stefanie Brickwede, who is also the head of AM at Deutsche Bahn (the German national railway), and who was recently a keynote speaker at the Additive Manufacturing Strategies (AMS) trade show in New York (February 7-9, 2023). As MGA’s director, Brickwede oversees an association of over 140 companies around the world, which, in their capacity as MGA members, combine forces to form 13 different working groups. One of the working groups, “Approval in Rail,” is specifically focused on safety issues.
As Brickwede explained at the conference, the considerations at play in exploring the use of AM for the rail industry are not only different from those in most other AM market segments. They are quite different from the considerations driving the use of AM for other forms of transportation, as well. Brickwede is especially effective at conveying that particular message.
3D printed wheel set bearing cover. Image courtesy of Deutsche Bahn
Managing director of MGA and head of AM at Deutsche Bahn, Stefanie Brickwede. Image courtesy of Ashley Alleyne/3DPrint.com
Because the load on trains has to be kept at such a consistent level, lightweighting parts, in-and-of-itself, isn’t necessarily a good thing, and in fact, could easily cause major issues including derailment. Thus, much more so than for planes or cars, the goal of AM for rail involves — and will increasingly involve to a greater extent — replicating the designs of parts that already exist. That detail dovetails with another point that Brickwede placed particular emphasis on at AMS, which is the singularly long-range planning involved in the procurement process for railway parts.
Since rail fleets are typically expected to operate for 30-50 years, decade-plus contracts for servicing parts is more or less the minimum that is standard in the industry. For instance, German industrial giant Siemens — a longstanding proponent of AM, as well as a member of MGA — recently signed the most valuable rail contract in its history, in India, for a length of 35 years. This means that obsolescence of spares is particularly worrisome for rail companies, since the discord between the changing needs of the broader industry, and one company’s specific contract, leads to constant phasing out of easy supplies of still-needed replacement parts. Brickwede pointed out in her keynote presentation that, currently, MGA members believe that as high as 10 percent of rail parts could be 3D printed, and eventually, 50 percent could be.
Thus, as with most other sectors that have a growing interest in advanced manufacturing, there is great potential in rail for companies to lower overhead by avoiding stocking up on unused spare parts, while also simultaneously facing shortages in others. Aside from increasing profitability with just-in-time production, though, the safety of rail transport, and especially freight rail transport, could be greatly aided by the fact that AM’s ideal use in rail involves reproducing existing parts as closely as possible. This is true if only because, since companies can leverage AM to increase both affordability of and access to already-proven spare parts, they can avoid ever having to choose between cost-savings and safety.
3D printed railroad brake caliper with electronic sensor. Image courtesy of Fraunhofer ILT
In addition, there are already projects, including one being worked on by MGA-member Fraunhofer ILT, involving the deliberate use of AM to enhance rail safety. One of the components of the Fraunhofer ILT project, for instance, involves incorporating embedded sensors in 3D printed rail parts. The ultimately purpose of that is to create an AI-driven system for informing rail companies about the status of their fleets, and alerting rail conductors to parts most urgently in need of replacement. This sort of application could be especially beneficial to the safety of freight rail transport, given the heightened complexity and hazard involved of moving such massive quantities of often toxic materials.
Finally, however, the fact that such a large, international, and multifaceted network of cooperating companies exists suggests the potential for near-term standardization of 3D printed parts in the rail industry on a level much greater than in planes and perhaps even cars. Moreover, this is a model that those other sectors are already starting to cultivate, as well. AM seems positioned to grow more immediately than some other industry 4.0 technologies precisely because it already has significant infrastructure in place on an international level, and the same can be said of the possibilities for AM in rail, compared to other AM market segments.