Plasser & Theurer ATMO: Urban Rail Grinding Solution

Introduction

Plasser & Theurer’s Automated Track Machine Oscillator (ATMO) trailer is designed for rail maintenance in urban environments, offering solutions for noise and vibration reduction. The ATMO utilizes block grinding technology for both preventive and corrective maintenance and is adaptable for use during revenue operations or non-operational hours.

Design and Features

The ATMO is designed as a compact, flexible trailer that can be pushed or pulled by almost any suitable rail-bound or high-rail vehicle, including regular tramway vehicles. It features its own integrated power supply for the grinding units, and a 2600-litre water tank for wet grinding (grinding output enhancement and spark suppression).

Block Grinding Technology and Operational Modes

The ATMO employs block grinding technology, capable of operating in two modes. In oscillating mode, the grinding blocks move back and forth with adjustable frequency and amplitude, while in sliding mode, they are dragged along the rail without oscillation. The grinding units, completely redesigned for urban applications, continuously adapt to the railhead shape, treating the running surface without gauge-face contact. A specially designed guidance system ensures the stones remain centered on the rail even in tight curves (down to 17m radii) and compensate for gauge variations. Each of the two grinding units per side holds two block grinding stones and the vertical grinding stone force can be varied within certain parameters. The ATMO can operate effectively at speeds ranging from 0 km/h (oscillation mode only) to over 30 km/h, with no minimum speed required for successful processing.

Performance and Testing Results

Extensive testing demonstrated metal removal of 0.01mm per pass at 4km/h in oscillating mode. The ATMO was used to remove corrugation at a grinding speed of 30 km/h with oscillation mode in 10 to 20 passes dependent on corrugation severity. This had significant impact on noise and vibration development showing train type dependent noise reductions of up to 8 dB.

Customer Applications

In Odensee, the ATMO successfully removed a hard-pressed, low-friction layer. In Graz, the ATMO effectively reduced corrugation, with results consistent with the tests, achieving significant reductions in longitudinal waviness after only three passes in some sections. In Cologne, the ATMO demonstrated its capability for both preventive grinding and the corrective removal of massive corrugation, requiring 160 passes for severe cases (1.1mm amplitude) and 60 passes for moderate cases (0.35mm amplitude) to be classified as corrugation-free. The ATMO was also successfully used to remove honeycomb-like surface structures created by rail milling. A single pass in oscillating mode at 0.8 km/h significantly reduced waviness in the 10-30mm wavelength range, bringing it below regulatory thresholds.

Conclusion

The ATMO is a versatile and efficient rail grinding trailer, proven suitable for both regular preventive maintenance and for corrective interventions to remove corrugation, and post-milling surface structures.

Company Summary

Plasser & Theurer: A manufacturer of railway maintenance machines and equipment, specializing in track maintenance solutions.

Technology

ATMO: Automated Track Machine Oscillator, a compact grinding trailer for rail maintenance.

Block Grinding Technology: A grinding method used by the ATMO, allowing for both oscillating and sliding modes.