HVE Develops Tool-Free 3D Printing Process for High-Speed Rail Components

A three-step process that skips the mold shop

For rail builders, making large outer-skin parts has meant thermoset composites, hand lay-up, and expensive tooling. That process is slow, labor-heavy, and hard to recycle. Hörmann Vehicle Engineering (HVE) wanted a different route, and after 34 months of work with Fraunhofer IWU, Fraunhofer IMWS, Lakowa, and Siemens Mobility, it now has one.

The 3D-FiberTrain project, funded by Germany's Federal Ministry for Economic Affairs and Energy and running from September 2023 to June 2026, produced a tool-free process chain for large-format, heavy-duty rail components. It combines three steps: granule-based extrusion 3D printing for complex geometry, a 3D tape-laying step that reinforces high-stress areas along the load path, and automated milling to hit final dimensions and surface quality. The whole thing uses thermoplastic material, so the parts can be recycled at end of life.

Validated on a 320 km/h train

To prove the process, the consortium picked two demanding parts from Siemens Mobility's ICE 3neo high-speed train: the nose and the front skirt. The Velaro MultiSystem platform reaches operating speeds up to 320 km/h, so these are not cosmetic panels. They have to survive aerodynamic loads, vibration, and impact.

HVE says the demonstrators showed lower manufacturing costs for small and medium production runs, shorter lead times because tooling steps disappear, and a reduced carbon footprint through more efficient material use and recyclability. Design changes also become cheaper: without a mold to rework, variants can be updated digitally.

Why thermoplastics matter for rail

The rail industry has a quiet sustainability problem. Most fiber-reinforced composite parts are thermosets, which means once cured they cannot be melted down or reshaped. HVE's shift to thermoplastic feedstock targets that directly. The parts can be repaired, reused, or recycled rather than landfilled.

This is part of a wider trend. Stratasys recently developed a flame-retardant glass-fiber nylon for rail production with Alstom and Siemens Mobility to meet EN 45545-2 fire standards while staying within a thermoplastic workflow. Deutsche Bahn has certified Essentium's flame-retardant materials for its High-Speed Extrusion 3D printer and is already producing tens of thousands of replacement parts. Rail operators are clearly betting that additive manufacturing works best when the material itself can be recovered.

What comes next

HVE is not stopping here. A parallel project called LeiPo-3D-FKM, running through December 2027 with TU Chemnitz and BMF GmbH, is working to additively manufacture a steel alloy that qualifies under Germany's FKM design guideline. That matters because most rail and engineering standards still assume conventional manufacturing. Until 3D-printed metals have their own design rules, adoption in load-bearing parts will stay limited.

The 3D-FiberTrain result is a practical step forward: a real process, tested on a real high-speed train, with recycling built in from the start. For an industry that still thinks in molds and batches, that is a useful reminder that the next generation of rail parts may never see a tool shop at all.