Nufox Rubber’s specialist reverse engineering expertise is helping keep Britain’s rail fleet running by recreating obsolete components with precision, quality, and sustainability in mind.
Rolling stock in the UK rail network is designed for long operational lifespans, with many trains remaining in service for 30 to 40 years or more. While this longevity delivers value for operators, it also creates a recurring challenge: over time, original component manufacturers discontinue parts, suppliers change ownership, and tooling is lost. When this happens, maintenance providers can find themselves searching globally for replacements that may no longer exist. In such cases, reverse engineering becomes essential.
This situation recently arose with the Class 158 fleet, where a rail maintenance and repair company needed replacement seals that had originally been manufactured in Spain but had since become obsolete. With no direct replacements available, the company turned to Nufox Rubber, a UK-based specialist in custom rubber extrusions and sealing solutions.
Based in Middleton, Nufox has built a strong reputation for designing and manufacturing complex rubber profiles for demanding applications. The Class 158 project highlights the type of specialist engineering capability required to support critical transport infrastructure.
Reverse engineering the seals was far from straightforward. The components needed to meet tight dimensional tolerances while also delivering the necessary mechanical performance and long-term durability. In the rail sector, materials must also comply with strict safety requirements, particularly for fire performance and low smoke emission.
Nufox’s technical team began by carefully analysing the original components. This included assessing the physical dimensions and profile geometry, evaluating the condition and composition of the existing rubber, and determining the most suitable polymer formulation to replicate or improve performance. Using advanced 3D modelling and CAD tools, the team recreated the seal profile digitally before designing the necessary extrusion tooling in-house.
Once the design stage was complete, Nufox manufactured prototype extrusions and supplied samples for evaluation. These samples were tested to confirm that they met the required dimensional accuracy, material properties, and functional performance. Following approval, full production could proceed, providing the rail operator with a reliable replacement for a component that had previously been unavailable.
The project also reflects Nufox’s broader involvement in supporting the future of UK rail manufacturing, with fire-rated EPDM materials to the EN45545-2 HL3 specification for both refurbishment programmes and new rolling stock projects. This includes work connected to the supply chains supporting HS2, where materials must meet demanding fire, smoke, and toxicity standards for modern rail environments.
Through active participation in organisations such as the Rail Forum Network, alongside its membership of the Made in Britain initiative, Nufox continues to engage with partners across the rail sector to strengthen the UK’s manufacturing ecosystem.
As the rail industry faces growing pressure to maintain reliable services while managing ageing fleets, the ability to recreate discontinued components has become increasingly important. Reverse engineering not only extends the operational life of existing rolling stock but also strengthens supply-chain resilience by reducing reliance on unavailable overseas parts. Companies like Nufox play a critical role in this process, demonstrating how specialist manufacturing expertise can keep Britain’s trains running safely and efficiently.
Nufox Rubber is a UK-based manufacturer with decades of experience in custom rubber extrusions and sealing solutions. Serving industries including rail, defence, construction, and manufacturing, the company combines modern design tools, in-house tooling expertise, and advanced production systems to deliver high-quality, bespoke rubber products.
This article was originally written by NUFOX Rubber Limited.