The HSM-Metro is a rail head treatment machine which brings together proven existing machine designs and concepts to provide a machine specifically aimed at addressing the challenges posed when working in metro systems.
The HSM-Metro consists of a milling machine with two milling units, a combined chip storage and grinding module and two locomotives. The milling machine vehicle design is based on the established D-HOB 2500 Rotational Planer with the milling modules taken from the High Performance Milling machine (HSM).
The combined chip storage and grinding module provides a highly compact solution for waste storage and post milling spark and dust free finishing by grinding. Each locomotive can provide sufficient power for both travel and working modes, whilst the combination of two locomotives adds operational flexibility.
The working vehicles and locomotives are connected via close couplings whilst the vehicle gauge, wheel set loads and traction are designed for as wide a range of metro systems as possible. Operational control of the machining process is via one of the locomotives. In addition, measurements of longitudinal and transverse profile, combined with eddy current crack detection, provide information demonstrating that the work completed is to the desired levels of quality and safety.
Mode of operation
Milling on each rail is synchronised and closely controlled via the onboard computer removing the potential for human error. Each milling wheel consists of a number of offset indexable cutting inserts arranged to achieve the desired profile. The waste chips from the machining process are removed from the cutting face through suction pipes to the waste storage module by means of a venturi generated vacuum.
The large diameter wheels minimise any scalloping effect on the railhead providing a very flat longitudinal profile which is further improved by an oscillating grinding unit, with a two metre fixed base, which follows the milling process. Grinding also removes any minor defects in both the transverse and longitudinal rail, the surface finish produced is of a very high quality showing only a very fine longitudinal surface texture lay in the direction of travel. The combination of milling and grinding described above results in very high quality rail head transverse and longitudinal profiles compliant to EN 13231-3:2012.
Range of application and performance
The HSM-Metro can be used for both corrective and preventive railhead treatment. Its primary aim is the removal of rolling contact fatigue and other track damage/wear such as head checks and squats. It also addresses rail head longitudinal and transverse profile wear such as grooves, corrugation, flattened and ridged rails. In addition to the above, and because of the unique combination of milling and grinding, the HSM Metro can also address rail damage due to wheel slip/slide and provide a rail with an acoustic signature compliant with existing pass-by noise requirements.
The HSM-Metro is designed for use in tunnels, on bridges (also with open track) and on tracks with conductor rails. The machine achieves an operating speed of up to 1,200 m/h.