3D Printing in the Railway Industry: reduce the need for spares with Roboze

Roboze’s additive manufacturing solutions for railway 3D printing

The railway has undergone a lot of changes from its invention in the 1800s. From hauling coal out of mines to transporting passengers at speeds of hundreds of kilometres per hour, railway systems are the backbone of land transportation and will continue to be for a long time. Railway industry includes trams, metro, intercity, freight railway, and passenger railway (high and normal speed), transporting millions of passengers and thousands of tons of cargo every day all over the world.

Maintenance of railway transportation: a major cost for railway operators

Since the lifetime of railway assets is usually in the range of 20-40 years, for electrical and mechanical systems, the reliability of a fleet of rolling stock is of paramount importance for reducing ownership costs and increasing efficiency. It has been stated that maintenance costs of rolling stock are about 30% of the lifecycle costs of a high-speed train, making it the largest operating cost along with energy consumption (also at 30%). Therefore, given the high costs that it consumes, maintenance is major area of focus for optimization in the railway industry.

Innovations in rolling stock maintenance

The maintenance of rolling stock is typically programmed either by mileage or by time, but this is changing. As has been the case throughout history, rail systems are no stranger to disruptive changes and there have been many advancements in how maintenance is performed. The next big leap is coming in the form of digitalization thanks to big data and advanced analytics solutions, which allow new maintenance techniques to be applied such as condition-based maintenance and predictive maintenance.

The objective of these techniques is the reduction of failures, unplanned maintenance, and to increase the lifetime of rolling stock. Performing maintenance on passenger cars is particularly important since people tend to take notice when coaches are not in a good state and so might view the train company unfavourably, taking their business elsewhere.

Issues with spare parts

Of the rolling stock maintenance costs stated above, about 40% accounts for material and spare parts. These must be sourced from somewhere, though, and that can be problematic. Spare parts for older trains are particularly difficult to come by since suppliers often no longer produce them. In this case a new supplier must be found and a new design and manufacturing process must be done, greatly increasing the cost and lead time. If only a few parts are needed, as is often the case, this further increases the cost.

Another solution is to stockpile spare parts, which can be done in a couple of ways. The traditional method is to order more parts than are needed and keep the extras in a warehouse. While simple, this solution is wasteful and expensive since spares can deteriorate in storage and cost money to store.

A final option is to stable rolling stock on an unused line and strip the cars for spares. This is far from optimal since one or several cars must be left to deteriorate just to supply needed replacement parts, instead of being used for their intended purpose (transport of freight or passengers).

Production of 3D printed train spare parts with Roboze solutions

As previously mentioned, many train spare parts have long lead times and elevated costs because production volumes are low. While this may seem like a problem, small lots are the speciality of 3D printing, and thanks to Roboze’s advanced metal replacement and material solutions, manufacturing of spare parts on-demand and just-in-time in the railway industry is guaranteed to be cheap and fast. This radically changes the ability of train operators to respond to maintenance problems, fixing a breakage in a timely manner and with a low cost, especially if the parts have particularly complex geometries. The design freedom inherent in 3D printing also allows parts to be optimised beyond their original design, for example by integrating several components together, optimising costs and reducing lead times.

Substituting metal with high-performance plastics immediately causes the mass of parts to be reduced by at least half. Taking this a step further, thanks to the design freedom inherent in additive manufacturing parts can also be optimised and re-designed with the objective of further reducing the mass. This is beneficial in a couple of ways:

• the reduced mass means lower energy and fuel consumption and thus lower costs over the lifetime of the rolling stock;
• a lower mass combined with 3D printing also means that less material is used for manufacturing, further reducing the cost and lowering the environmental impact of the manufacturing process.

Digital warehouse dramatically cuts the costs of storage

Furthermore, once a spare part has been designed and 3D printed, it can be stored digitally without the need for physical space. This concept is known as digital warehouse and is very cost-effective and efficient solution to traditional storage of spares. Gone is the need to stock several parts in case they might be needed! When a replacement component is required, the appropriate file is simply selected from the digital catalogue and sent directly to print, dramatically cutting the costs and manufacturing times.

Roboze 3D printing materials: application in the railway sector

Roboze has a wide portfolio of materials to fit every application in the railway industry. For example, Polypropylene is the ideal solution for printing a replacement flapper for train toilets (wide chemical compatibility, low weight, and excellent impact resistance). Replacement of parts for toilet drain pumps can be done with Carbon PA (strong mechanical properties comparable to aluminium AA1050A). Cabin components such as broken passenger armrests can be printed out of ULTEM 9085 (low FST evolution, UL94-V0 at 1.5 mm and 3 mm or 0.059 in and 0.118 in).

Thanks to high-performance materials like Carbon PA (ultimate tensile strength of up to 88 MPa and an elastic modulus of up to 3.9 GPa) Roboze’s 3D printing solutions are not just limited to spare parts for trains. Often custom tooling for use in shop floors is needed, and Roboze’s metal replacement specialization offers the prefect manufacturing method. Tooling, jigs, and fixtures with highly customised geometries can be ready to use in a matter of hours, replacing heavy and cumbersome metal parts with lightweight and safe-to-handle plastic ones that have comparable, if not better, properties. The additive nature of 3D printing also means that material wastage is greatly reduced compared to traditional manufacturing, further reducing costs and environmental impact.

Example application: component for bed lowering and raising mechanism in sleeping cars