3D printed grab handle.
Once upon a time, an asset management company in charge of a third of the UK’s rolling stock entered York’s National Railway Museum, identified ten air conditioning vents in the driver cabins of its exhibits, and took off with them to install on trains currently in service.
It was a desperate measure, made after an automotive company gave a minimum order size of 10,000 to manufacture replacements. Angel Trains is faced with a predicament like this all too often. The trains they lease are in operation, on average, for 20 years, with some having lasted half a century before being put into retirement. And while, that’s the goal for a company that generates profit by maintaining rail vehicles through regular refurbishment, those trains are also often fitted with parts that are obsolete, originally supplied by companies no longer in business, with design drawings nowhere to be found. In the case of the air vents, drivers have been known to refuse to operate trains without working air conditioning, while interior carriage parts like armrests and grab handles need to be replaced to avoid hefty Department for Transport fines.
At TCT Show, Angel Trains was proud to announce that Chiltern Railways, one of its customers, had avoided those fines recently thanks to a collaboration with Stratasys. In the run up to the show, where James Brown, Data and Performance Engineer at Angel Trains, delivered the opening keynote, seven grab handles and four armrests produced with Stratasys’ Fortus 450mc Production 3D Printer in ULTEM 9085 had been installed on an in-service passenger train running out of London Marylebone station.
“We saw what was going on in Germany,” Brown explained, referencing Deutsche Bahn’s prolific additive manufacture of thousands of spare parts since 2015, “saw the potential for [3D printing] and realised our supply chain wasn’t really doing anything with it. The aim behind this is to get the approvals in place, get the technology in place, and also give a bit of a kick to the supply chain. ‘Do this or we’ll do it for you.’”
3D printed armrest.
The armrest and grab handle components represent the first-ever compliance of 3D printed parts to the EN45545-2 UK rail industry standard having come through a number of fire, smoke and toxicity tests. Engineering consultancy DB ESG, a Deutsche Bahn company, oversaw these tests and helped to verify the design, production and finishing of the parts. They were first 3D scanned before design work was conducted straight from that captured data into manufacturable CAD models with automated design tools where possible. These digital models would then go through a design review process and given the green light to be manufactured. The armrests were produced within a week, a 94% lead time reduction, while the grab handles were obsolete parts that would have taken around two and a half months to produce and required a 15,000 GBP tool to be cut. With 3D printing, it took three weeks.
More gains are on the way. Brown instructed the designers who worked on the parts to leave nothing to chance, modelling the armrest, for example, as a solid block of material with no geometric optimisation. With future iterations, they’re looking to halve the weight of that component. Meanwhile, around 120 other parts have so far been digitised, a target of 100 installations has been set by this time next year, Great Western Railway is the latest operator to commit to trialling printed parts in the next few months, and a digital inventory is in the works.
In partnership with Stratasys and DB ESG, Angel Trains is looking to put the museum raids behind them once and for all.
“We want to enable a supply chain that is faster, cheaper and responsive to our operators’ needs,” Brown summarised. “And we believe digital manufacturing is the answer.”
