PLASSER & Theurer has unveiled an Automatic Track Machine Oscillator (ATMO) track maintenance unit, a world-first, which was developed as part of the Shift2Rail (S2R) joint undertaking.   

The ATMO combines conventional whetstone grinding with oscillating grinding. The machine employs two grinding saddles, each fitted with two grinding stones per rail head. A hydraulic mechanism moves the grinding saddles horizontally, in the longitudinal direction of the rails, with variable frequency. By constantly moving back and forth while travelling at up to 8km/h, the machine can achieve precisely fine-tuned grinding with a single pass.  

Oscillating grinding is recommended for areas prone to developing rail defects, such as stations or stops, where waves can form, or other hotspots where corrugations occur. 

The ATMO trailer can be remotely controlled from the traction unit, and can undertake conventional grinding at speeds of up to 30km/h. The four-axle unit can operate on track curves with a radius of 17.25m, and traverse curves with a radius of 16.25m. The grinding stones are automatically aligned to stay above the rail head when operating around curves, and the grinding stones can remain lowered when travelling over switches and crossings.  

The standard-gauge ATMO prototype employs a water-cooled, sound-insulated 100kW diesel engine with exhaust after-treatment, and is equipped with a 2800-litre water tank for wet grinding, providing a thin water film which improves grinding output and prevents flying sparks.   

The development of the new system was started after the completion of a market study by Vienna University of Technology under the S2R JU. Design and manufacturing were completed by Plasser and Theurer. A test phase was launched in the middle of 2020, with the vehicle tested through various situations by Vienna public transport operator Wiener Linien.