2019 Rail Transit Session
Rail Milling in North America – A First Look
Despite being introduced about 25 years ago rail milling is still considered a relatively young maintenance technology, especially when considering that this technology so far has not been used in North America.
Rail milling is a spark-free rotational cutting process resulting in the formation of metal chips to be cut out of the rail surface. Rail milling achieves low to high metal removal rates in one milling pass. The process heat mostly transfers into the metal chips and the milling tool. The metal chips are collected on board the milling machine and can be recycled afterwards. In order to produce a noise-optimised surface finish a polishing unit (completely enclosed longitudinal grinding wheel with a small off-set angle) is included in the machine immediately followed to the milling unit. Compared to rail grinding, rail milling is a slower process. However, the slower process speed can be compensated by higher one-pass metal removal capabilities.
For the first time in history RHOMBERG SERSA NORTH AMERICA is operating a LINSINGER rail milling machine in North America at transit systems to carryout milling services. This paper will focus on the rail milling operation at the subway of TTC in Toronto. The whole milling campaign will be analysed, starting with the preparation work, looking at an actual night shift and discussing the achieved results as well as lessons learned. Beside the TTC operation, some specific examples from Australia and Europe will also be used to complement this paper.
Finally, an outlook will be given about future plans with respect to rail milling at TTC and other transit systems in North America.