New rail grinding machine for light rail unveiled
Austrian manufacturer Plasser & Theurer has presented a new rail grinding machine that has been completely redeveloped for light rail and trams. The ATMO (Automatic Track Machine Oscillator), developed as part of the Shift2Rail joint undertaking, ensures trains run more quietly on smoother rails.
The ATMO combines the classic stone grinding with oscillating grinding. Oscillating grinding is particularly recommended for areas that are more susceptible to rail defects. For example, the approach area of stops, where the formation of waves can occur, or other ‘hotspots’ with ripples. With oscillating grinding, a hydraulic system moves the two grinding saddles horizontally in the longitudinal direction of the rail. The machine has two grinding stones per rail head, which move at a variable frequency.
The constant back and forth motion when driving slowly, up to eight kilometres per hour, results in more precisely fine-tuned grinding with a single pass of the machine. In the standard gauge ATMO prototype, the required oil pressure for the process is generated by a water-cooled, sound-insulated diesel engine with 100 kilowatts and exhaust gas after-treatment.
Designed for urban use
The new track and turnout grinding vehicle for the tram sector is towed by a railcar or road-rail vehicle. The flat grinding vehicle is unmanned, its functions are remotely controlled from the towing vehicle. The ATMO can do conventional grinding in both directions at speeds of up to 30 kilometres per hour and can therefore ‘swim’ in between regular tram operation. Road closures for the work are no longer necessary. A challenge in urban areas are sometimes relatively tight arc radius. The four-axis grinding machine can process radii down to 17.25 metres and drive the radius down to a minimum of 16.25 metres.
The grinding stones are aligned to stay above the rails when going over a curve, so that they are always above the rail head. In contrast to classic grinding vehicles, the grinding stones do not have to be lifted when driving over switches and crossing areas. The new machine has a 2,800-liter water tank for wet grinding. The thin film of water improves the grinding performance and prevents flying sparks, which pose fire risks in dry conditions and in tunnels.
The rail grinding machine ATMO was created in cooperation with industry, university and infrastructure operators. The theoretical basis for the product was provided by a market study by the Vienna University of Technology as part of the Shift2Rail joint undertaking. As an industrial partner, Plasser & Theurer contributed its know-how in design and implementation.
The first ATMO test phase started in mid-2020 under various conditions on the tram tracks of the Vienna public transport operator Wiener Linien. Improvements of all kinds in the wheel-rail system are the subject of the European Shift2Rail research initiative (S2R). It is part of the IN2TRACK (I2T) project launched in 2016, of which one of the goals the enhancing and optimising the switch, crossings and track systems in order to ensure optimal line usage and capacity.