HSG-city Grinding Machine

Flexible. Fast. Smart.
Grinding short track sections within the timetable.

The rails of public transportation and short-haul routes also sustain damage in the form of wear, corrugations, slip waves and head checks caused by traffic loads, heavy acceleration and heavy braking. Our solution for light rail systems: smart, prognostic maintenance with the HSG-city.

If rails are not machined, the corrugations that form will increase noise emissions for residents in the area. Furthermore, the strain on the rail material from the rolling stock will also make it necessary to perform premature and expensive rail replacements.

High Speed Grinding (HSG) removes minor and median rail damage, reliably prevents new defects from forming and effectively reduces noise emissions produced by rail traffic by up to 10 decibels. HSG-city is currently the fastest light rail and short-haul grinding machine on the market. With its variable operating speeds currently between 8 and 60 km/h, it can be scheduled to fit in with any timetable and without any track closures or preparation work whatsoever.

Its compact shape allows it to fit inside any structure gauge. It can operate traveling either forwards or backwards, which allows it to be either pulled or pushed by many different types of traction vehicle, e.g. road-rail vehicle. What's more, it can be very easily controlled from the traction vehicle via remote control.



High Speed Grinding

As little as possible and as much as necessary – thanks to intelligent maintenance planning and sophisticated technology, High Speed Grinding deliberately removes only a little of the valuable rail metal. Only the hardened surface layer is removed, which at the same time optimizes the rail's cross-sectional and longitudinal profiles.

The HSG-city achieves this thanks to its special grinding wheels, which are arranged in rows and made to rotate across the rails by the train's forward motion. What is so special here is the infinitely variable adjustment of the angle of the grinding wheels, which allows them to be positioned at the exact angle required to achieve the desired results. And since they rotate passively and the hydraulically controlled grinding pressure is constantly monitored while the train is in operation, grinding defects such as periodic drag marks or bluing are ruled out right from the outset.

Especially efficient and safe: Two rows of grinding wheels are mounted in a revolving grinding unit, allowing an easy change-over from used grinding wheels to new ones while the train is in operation. The HSG-city can grind a 30-km track section without stopping.

No track closures or preparations

Quick and safe – The HSG-city is the only grinding machine in the world that can machine Vignole and grooved rails at speeds of 8 to 60 km/h without disrupting rail traffic. Its deployment can thus be perfectly scheduled to suit the timetable and the local conditions, which means that in the future you won’t need to close tracks or carry out elaborate preparation work. Thanks to the special positioning of the grinding unit, switching equipment does not need to be dismantled beforehand and normal railway operations can resume immediately after machining.e.

Hardly any dust or sparks

Clean, efficient and particularly suitable for use in tunnels – any dust produced is very effectively vacuumed into the integrated bunker by the dust extraction system above the HSG-city's grinding wheels. This bunker has a large storage capacity, so grinding 30 km of track in a single shift without emptying the bunker is no problem at all. What's more, the rotating grinding wheels produce minimal sparks.

Noise reduction

Quiet and comfortable – One of the main sources of rail noise is the rolling sound emitted by the wheels. The more roughness or slip waves in the rail surface, the more noise is generated. High Speed Grinding smoothens out the rail, optimizing the wheel-rail contact and reducing the rail surface roughness that produces noise. Preventive rail maintenance using the HSG-city considerably improves rail acoustics by between 3 and 10 decibels, which results in distinctly quieter rail traffic. And not only that: the machining itself is comparatively quiet. This significantly reduces the stress for nearby residents, especially where rails are machined at night in urban areas.

Smart Maintenance

Supplementary to its role as a grinding machine, the HSG-city will in the future also serve as a diagnostics vehicle equipped with measuring and testing technology that measures the longitudinal and cross-sectional profiles as the machine passes over the rails. The data collected forms the basis of the revolutionary maintenance planning app developed by Vossloh called Smart Maintenance, which allows you to control the maintenance of your network more easily and efficiently than ever before. Find out more about Smart Maintenance.


Some of the places where the HSG-city is used include the Rheinbahn in Düsseldorf, Rostock's tram network, the Beijing Metro and the Copenhagen Metro.


• Grinding wheels: 24 in use at any one time

• Operating speed: 8–60 km/h

• Non-stop grinding: 30 km

• Rail roughness: Ra < 10 μm

• Process parameter documentation

• HSG-city controlled remotely from the traction vehicle

• External traction, pulled or pushed, thanks to its low design height

• Works in either direction

• Fits inside any structure gauge (including the London Tube or the "Berlin klein")