~ Smaller control and auxiliary systems could decide whether digital rail delivers on its promise ~
The UK’s rail sector is undergoing one of the most ambitious modernisation drives in decades. New signalling frameworks, digital control systems and nationalisation reforms dominate the headlines, promising a more reliable network. Yet for all this investment, reliability often depends on smaller, overlooked systems. As trains become more automated, the performance of mechanisms such as signalling equipment, door assemblies and environmental controls increasingly determines whether the network runs smoothly or grinds to a halt. Here, Chris Johnson, managing director of bearing specialist SMB Bearings, explores why the industry’s reliability challenge is as much about precision motion in small systems as it is about digital transformation
The Government’s plan to create Great British Railways (GBR) aims to resolve long-standing issues of fragmentation, inefficiency and inconsistent service quality within the UK network.
A recent report from The Department for Transport concedes that despite substantial investment, the system remains too complex and operationally divided to deliver the reliability passengers expect. By unifying track and train under one guiding body, GBR is designed to simplify accountability and coordination across the network. Yet structural reform alone cannot guarantee reliability.
In discussions about rail modernisation, the focus naturally falls on “high-profile” programmes such as digital signaling and network electrification. But while those initiatives 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 might not carry the same glamour as new control software, but they form the mechanical backbone of automation. A seized bearing in a point machine or ventilation fan can immobilise a section of track or compromise onboard safety systems. When even brief downtime can cascade into missed connections and timetable disruption, the industry’s reliability equation begins with mechanical integrity.
Digital ambitions meet physical realities
The rail 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.
Smaller systems, greater scrutiny
Auxiliary systems now carry more operational importance than ever. Take onboard doors, a single failure can halt a service, delaying hundreds of passengers. Or consider heating, ventilation and air conditioning (HVAC) systems, where a fan motor fault can lead to carriage downtime, particularly in extreme weather.
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 punctuality, yet they often fall outside headline maintenance programmes. 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.
Engineering resilience from the ground up
So how can the industry strengthen reliability at this level? Part of the answer 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.
This is where bearing selection becomes a strategic decision rather than a routine one. 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.
Reliability lessons from sectors such as aerospace and food-grade automation also apply to rail. By selecting corrosion resistant bearings or self-lubricating materials, engineers can minimise wear, reduce maintenance frequency and protect uptime.
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.
These are not headline investments, yet they have an outsized impact on network performance. A fault prevented in a minor subsystem can save hours of disruption and thousands of passenger delay minutes.
As the UK rail network evolves, reliability will depend on how well its smallest mechanisms support its largest ambitions. 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, not at each other’s expense.
Speaking with a bearing specialist can simplify the bearing selection process, reach out to a bearing specialist through the website to learn more.
