• Reduces friction variability • Prevents micro-welding • Improves torque-to-tension consistency • Reduces maintenance time and MTTR
Application should be limited to the friction interfaces only, using controlled quantities.
Friction in wire ropes: Internal, not external Wire ropes consist of multiple strands and wires twisted around a core. While they are lubricated during manufacture, in-service lubrication remains critical.
The primary friction occurs internally, between wires and strands during loading. As the rope is tensioned, wires experience elastic and sometimes plastic deformation, generating relative motion under extremely high loads and very low speeds.
This is a classic boundary lubrication scenario. However, lubricant penetration into the rope core is difficult, creating a trade-off between high viscosity lubricants with excellent load-carrying capacity but poor penetration, and low viscosity lubricants with better penetration but reduced film strength.
For this reason, wire rope lubrication often uses a combination approach: • Low-viscosity oils with solid lubricants for penetration
• Higher viscosity oils or greases for external protection and corrosion resistance
Lubricants must also protect against environmental exposure, particularly in marine, mining, and offshore applications.
Friction in railway tracks: Lubricating without losing traction
Railway wheel–rail contact requires high friction for traction and braking, so lubrication is counterintuitive. However, in curves, wheels must compensate for different travel distances on the same axle.
Unlike road vehicles, trains do not use differential gears. Instead, wheel profiles allow compensation through sliding at different effective diameters. This sliding generates high contact stress, low relative speed, and significant wear and noise.
Environmental considerations are also critical, making biodegradability a common requirement.
Conclusion: Friction awareness as a reliability tool Across couplings, valves, bolted joints, wire ropes, and railway tracks, one theme is consistent: the most critical friction points are rarely the most obvious ones.
In most of these applications, friction occurs at low speeds, under high loads, with short or intermittent motion, placing them firmly in the boundary lubrication regime. Failure to recognise this leads to incorrect lubricant choices and reduced equipment reliability.
By accurately identifying friction interfaces and understanding their operating conditions, lubrication professionals can select lubricants with appropriate viscosity and additive systems, apply lubricants more effectively, reduce wear, energy losses, and downtime and transform lubrication from routine maintenance into a reliability strategy.
Understanding where friction truly occurs is not academic. It is one of the most powerful tools available to lubrication engineers seeking to improve asset performance and longevity.
interlub.com
Lubrication is therefore applied selectively to rail curves, targeting the flange or gauge face rather than the running surface. These lubricants operate under boundary conditions and typically use moderate base oil viscosity, high concentrations of solid lubricants and strong EP performance.
LUBE MAGAZINE NO.191 FEBRUARY 2026
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