Why do they grind railway tracks?

Tracks are ground to remove surface defects like corrugation (waves) and Rolling Contact Fatigue (cracks). This extends the life of the rail, ensures a smooth ride, and reduces noise.

Does rail grinding weaken the track?

No, it actually strengthens the track's longevity. Although it removes a small amount of metal, it removes the fatigued surface layer where cracks form. Leaving the cracks would lead to much deeper structural failure.

What causes the sparks during rail grinding?

The sparks are caused by the friction between the high-speed rotating abrasive stones and the steel rail. It is essentially a large-scale version of using a bench grinder on a piece of metal.

The Art of Resurfacing: Why Rail Grinding is Essential

Rail Grinding is the process of re-profiling the rail head to remove defects and extend track life. Discover why “shaving” the steel prevents dangerous cracks and reduces noise.

December 9, 2025 11:02 am

What is Rail Grinding?

Rail Grinding is a specialized maintenance procedure performed by heavy-duty trains equipped with abrasive grinding stones. As these machines travel along the track, they physically remove a thin layer of metal from the surface of the rail head.

While it may seem counterintuitive to remove steel from a rail, this “shaving” process is vital for restoring the correct transverse profile (shape) of the rail, ensuring a perfect fit with train wheels. It acts as a reset button for the wheel-rail interface.

The Two Enemies: Corrugation and RCF

Grinding is primarily used to combat two major defects that naturally develop over time:

Corrugation: Wavy irregularities on the rail surface (like a washboard) that cause intense vibration and a loud “roaring” noise.
Rolling Contact Fatigue (RCF): Microscopic cracks caused by the immense stress of wheels rolling over the rail. If not ground away, these micro-cracks grow deep into the rail, eventually causing it to snap (Rail Break).

Preventative vs. Corrective Grinding

Modern infrastructure managers have shifted from “fixing it when it breaks” to “grinding it so it doesn’t break.”

Feature	Preventative Grinding	Corrective Grinding
Timing	Regular intervals (e.g., every 6 months)	When defects are clearly visible
Metal Removal	Minimal (0.1mm – 0.2mm)	Significant (>1.0mm)
Speed of Operation	High speed (up to 20 km/h)	Slow speed (multiple passes required)
Goal	Stop cracks from starting (Magic Wear Rate)	Remove deep cracks/corrugation

Acoustic Grinding: Shushing the Train

In urban areas, grinding is often performed specifically for noise control. Rough rails create high-frequency noise. By polishing the rail surface to a mirror-like finish, Acoustic Grinding can reduce pass-by noise by several decibels, improving the quality of life for residents living near the tracks.