In discussions about rail modernisation, the focus is falling on high-profile programmes such as digital signalling and network electrification, however the bearings, couplings and seals are critical to reliability. Chris Johnson, managing director of SMB Bearings comments.
According to a recent report from The Department for Transport, despite substantial investment, the UK rail system remains too complex and operationally divided to deliver the reliability passengers expect. The Government’s plan to create Great British Railways (GBR) aims to resolve long-standing issues of fragmentation, inefficiency and inconsistent service, however while programmes such as digital signalling and network electrification will reshape the network’s long-term efficiency, the short-term risk to reliability often originates elsewhere.
According to the Office of Rail and Road’s Passenger Rail Performance statistics, a significant share of service delays continues to stem from infrastructure and asset faults on the network. These include issues in signalling systems and point machines, areas where auxiliary motion components such as actuators, linkages and motor assemblies must operate with consistent, low-friction rotation to maintain reliability.
Smaller components such as bearings, couplings and seals are essential for automation. A seized bearing in a point machine or ventilation fan, for example, can immobilise a section of track or compromise onboard safety systems. The industry’s reliability equation therefore begins with mechanical integrity.
Digital transformation
The industry’s digital transformation is often framed as a software challenge, yet every digital system ultimately drives a physical mechanism. For example, the European Train Control System (ETCS) relies on thousands of electro-mechanical interfaces that translate electronic commands into motion, from actuated switches to sensor rotors. These components must perform reliably in harsh environments of vibration, temperature variation and exposure to dust or moisture.
At the same time, the rail industry is adjusting to significant organisational and regulatory change. The Office of Rail and Road’s Business Plan 2025–2026 outlines its commitment to supporting Government reforms aimed at improving efficiency, reducing bureaucracy and preparing the ground for Great British Railways. It highlights how the use of new technologies and streamlined processes can enhance productivity and strengthen the rail sector’s long-term resilience.
That makes the quality of small rotating parts, particularly bearings, critical. Bearings that resist corrosion, tolerate misalignment and maintain lubrication integrity extend operational life and reduce the likelihood of unplanned faults between service intervals.
Precision bearings
Auxiliary systems now carry more operational importance than ever. With onboard doors, for example, a single failure can halt a service; or with HVAC systems a fan motor fault can lead to carriage downtime.
Trackside monitoring equipment faces similar challenges. Cameras, sensors and inspection units all depend on miniature precision bearings to deliver stable, low-noise operation under continuous use. Each of these systems contributes to passenger safety, comfort and train punctuality.
As rail networks expand automation, engineers must recognise that reliability depends on both data connectivity and physical component durability. The best digital diagnostics in the world cannot compensate for a mechanical point of failure hidden within a compact assembly.
Strengthening reliability at this level partly lies in closer collaboration between mechanical and control engineering disciplines. When specifying components for signalling or onboard systems, engineers should consider not only load and speed but also environmental exposure, sealing performance and available lubrication intervals.
Using high-grade stainless steel bearings, ceramic hybrid or specialist polymer bearings can significantly reduce friction and extend service life. Advanced grease formulated for temperature extremes or moisture resistance further improve reliability in trackside and undercarriage applications.
In signalling actuators, polymer bearings can deliver consistent torque at low speeds without the need for regular relubrication. In door mechanisms or HVAC assemblies, hybrid bearings with ceramic balls can withstand frequent cycling and vibration, maintaining smooth, quiet operation across a long service life.
Keeping trains moving
Digital transformation cannot succeed without mechanical dependability, and the systems that keep trains moving, literally, deserve as much engineering attention as the code that controls them. By designing resilience into every rotating element, the industry can ensure that automation and reliability progress together.
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