The Railway Challenge
Established by the Rail division of the Institution of Mechanical Engineers (IMechE) in 2012, the IMechE Railway Challenge provides students, apprentices and graduates with an opportunity to showcase their engineering skills, expertise, knowledge, and business acumen. Participants are required to design and manufacture a miniature (10¼” gauge) railway locomotive, with entries subjected to a number of track-based and presentational challenges.
Alstom joined the Railway Challenge in 2017, launching their entry at Stapleford Miniature Railway in Leicestershire at the end of June this year. Contrary to the ‘miniature’ description, the demands of the Challenge are far from small! Recognising the complexity of the task, Alstom’s team of graduate engineers began work on their entry back in 2015. Over a period of nearly two years, the Alstom engineering graduates and apprentices worked diligently on the locomotive design in addition to their day-to-day roles and training placements. To complete their locomotive design, the team engaged the support of Protolabs—an approved supplier to Alstom.
One of the challenges of manufacturing a one-off component, is to keep costs as low as possible and certainly within budgetary constraints.
For their locomotive design, the team needed to identify a method to manufacture two recessed brackets to hold the locomotive’s emergency stop button. The train design required the brackets to fit inside a 66mm hole in the body panel, to enable it to be bolted into place.
Team member Cillian Lynch, who designed the assembly, proposed 3D printing the parts. “3D printing seemed the logical solution as we couldn’t justify injection moulding tooling costs or cold forming for such a small order volume. These manufacturing methods would require expensive tooling to be made. In addition, the design would require a tool steel die and hydraulic pressing—a-high skill process, which is expensive and only viable for mass production. Alternatively, if 3D printing didn’t exist, welding or machining would offer the most viable option which, in comparison, would be far more time and resource consuming.”
Green light from Protolabs
Cillian and his colleagues presented their 3D printing project proposal to Protolabs and were delighted to receive a favourable response in terms of manufacturing and financing (Protolabs sponsored some of the parts produced). The support of Protolabs’ considerable experience in rapid prototyping proved invaluable in terms of manufacturing design guidance for their locomotive entry.
“As part of our project, we thought it important for us to demonstrate new, cost effective, manufacturing methods that the rail industry can use to develop its competitive edge. Looking to the future, we can see 3D printing technology becoming increasingly prominent in train manufacturing, repairs and upgrades,” said Cillian.
To ensure their part CAD models were fit for purpose, the Railway Challenge team took full advantage of Protolabs’ free automated feedback. The seamless approach of being able to submit CAD files electronically, followed by a rapid ‘quotation’ response and on-line order capabilities made ordering parts very straightforward for Cillian and his colleagues.
“We were very impressed with Protolabs’ web-based tools. There was no need for lots of email, purchase orders or cumbersome admin, all of which carry risks of misunderstanding and delay. In our situation, we only had to revise the design once – essentially we thinned the bracket to increase clearances for assembly and operation. Then it was ‘good to go’ and we instructed Protolabs to proceed; all carried out online.”
Bringing it all together
Alstom received their parts just three weeks after placing the order; their fabricated metal-work parts from other suppliers took considerably longer. After an initial inspection to confirm that the part had the correct dimensions with Vernier calliper, there was no need for any stress testing for a non-structural part, and so the brackets were ‘right first time’.
When put to the test during the competition, Alstom were delighted that their entry came first in the business case challenge, fourth in the design challenge and eighth overall. As a first time entrant in a field of 12 teams this was a good result – particularly against teams who had refined their entry every year since 2012.
Spurred on by the favourable competition result, Cillian and fellow team members are planning to enter again in 2018. As the rules of the Challenge evolve each year, the locomotives entered will need to be developed further to comply with IMechE competition specifications which are updated annually. Cillian ponders, “For next year’s challenge, it’s probable that we will make more use of 3D printed parts.”
“3D printing certainly allows designers enormous freedom compared with traditional manufacturing constraints; making the once impossible, possible. We learned a great deal from the experience of working with Protolabs, everyone was extremely helpful and we are really grateful for the support received to bring our project to life.” said Cillian.