VOSSLOH’s new three-car HPM1 high-performance rail milling train, which was developed in cooperation with MFL, is designed to be self-propelled at the work site, but locomotive-hauled between sites to avoid the need to install multiple signalling systems on the train. It has a maximum line speed of 120km/h.


Vossloh DecThe rail milling train is fitted with two 1400mm-diameter milling wheels, which can mill at 1.6-2km/h. Vossloh says this is faster than other machines which mill at 0.7km/h. Up to 3mm of material can be removed in a single pass.

The cutting blades are housed in cassettes to accelerate the process of blade replacement, which takes around 10 minutes per cutting wheel.

Face-milling finishing wheels with a diameter of 300mm remove any residual waviness after the main rail milling has been completed. This avoids the need to use grinding stones for rail finishing. Metal chips are extracted from the site and stored in a hopper on the train. Vossloh plans to install an eddy-current measuring system on the HPM1 in the near future.

The train is built to W6A loading gauge and is powered by two Caterpillar C18 diesel engines which are certified to the European Union’s Stage 3b emissions standard while being prepared for Stage 4. The milling train is between 61.7 and 84.12m long, 2.61m wide, and has a maximum height of 3.94m.

Vossloh also demonstrated its HSG-City grinding machine, which has since been approved by the German Railway Authority (EBA) for operation on main line and suburban rail infrastructure as a heavy ancillary vehicle capable of speeds of up to 60km/h.

“This latest approval allows us to increase its use, particularly in rapid transit interurban networks,” says Mr Marcel Taubert, Vossloh Rail Service’s managing director. “Considering our ambition to acquire new European customers for this preventative grinding technology, we view the EBA approval as a mark of quality that will attract international attention.”

HSG-City utilises Vossloh’s HSG technology which is based on the principle of circumferential grinding using specially-shaped stones which, unlike conventional grinding stones, are free to rotate during the grinding process on straight track sections.

HSG-City has 24 grinding wheels, which can be exchanged in minutes. Grinding can be carried out at between 8 and 60km/h depending on the traction unit hauling it which can be a road-rail vehicle or an LRV for example. Grinding is logged digitally and controlled remotely from the traction unit.

HSG-City is unidirectional and designed for multiple operation. It is capable of grinding up to 30km of rail non-stop. The machine produces a facet-free grinding pattern with a surface quality of under 10um with a finish grind of 0.1mm after 10 to 12 passes.

Vossloh says that targeted use of the HSG-city is a more economical option than using larger conventional vehicles.

The next step for Vossloh is to secure approval for HSG-City to maintain “specially-monitored” track with qualification tests taking place up to the end of the year as part of the Federal Ministry of Transport and Digital Infrastructure’s I-Lena noise emissions reduction project.

Vossloh is currently supplying grinding units for a self-propelled HSG2-S grinding train being built by a Chinese company for operation in China.

While grinding trains are typically used to grind turnouts, the reduction in track possession times is making this harder to schedule. In response to this challenge, Vossloh has developed its Flexis system which comprises a group of typically six hand-controlled machines, which can be deployed and removed from the track quickly.

Some Flexis machines are optimised for either cross or longitudinal rail profiles. They can machine turnout components, such as switch blade points, wing rails, or frogs, which are inaccessible to larger rail grinders. Flexis is designed for regular inspections, preventative grinding, reinstatement to a less advanced state of wear, reprofiling crossings, and corrective maintenance. However, Flexis is not suitable for major rail correction such as correcting large head checks.

Mini milling

Vossloh also exhibited its demonstrator MMM mini-milling machine for use on short sections. There is a measuring system at the front of the machine, and according to Vossloh, it is possible to achieve any rail profile, with the MMM able to remove a maximum of 2mm in one pass. The two-axle 4.1-tonne machine is 3.1m long and 1.9m wide. A ramp is used to get the machine on and off the track.

Infrastructure managers will typically use a measuring train to obtain an overall picture of track condition, and will despatch small “walking” machines to determine the exact nature of any flaws detected. One such machine being demonstrated by Vossloh was the RRR Road Rail Runner ultrasonic rail flaw detector which can operate at up to 5km/h when a track inspector is walking behind it. The RRR uses nine probes to examine the rail head, web and foot at different angles to detect internal rail cracks. Data showing the status of the rail is collected, recorded and analysed in a robust removable 10-inch IP65-rated tablet computer, and any irregularities are displayed in real time.

The software provides multiple B-Scan and A-Scan views either simultaneously or in separate groups. Sensitive areas can be scanned and recorded repeatedly. GPS coordinates can be saved while photos can be taken of any squats or head checks observed. The RRR can store data covering up to 50km and weighs up to 25kg.

Vossloh launched a turnout management service for industrial railways three years ago as it recognised that while many industrial railways used to have their own in-house track engineers, the trend is now towards outsourcing this specialised activity, preferably to a single company. The turnout service ranges from track inspections to maintenance, repair or complete turnout replacement.

Finally, visitors were given a tour of Vossloh’s new Hamburg welding plant, one of three such facilities in Germany, with the other two located in Leipzig and Nuremberg. Together the three plants supply about 3.2 million metres of long-welded rails to sites in Germany, Denmark and Sweden to provide a just-in-time service.

The Hamburg plant has three production lines: one for welding different profile rails, one for flash-butt welding, and one for rail milling. The latter is used either to remove the decarbonised layer from new rails or to remove defects from old rails.