\r\nThe three-car HPM1 train is designed to be self-propelled at the work site, but locomotive-hauled between sites, with a maximum line speed of 120km\/h, to avoid the need to install multiple signalling systems.\r\n \r\nThe train is fitted with two 1400mm-diameter milling wheels which can mill at 1.6-2km\/h. Vossloh says this is faster than other machines which mill at 0.7km\/h. Up to 3mm of material can be removed in a single pass.\r\nThe cutting blades are housed in cassettes to speed up the processes of blade replacement, which takes around 10 minutes per cutting wheel.\r\n300mm-diameter face-milling finishing wheels remove any residual waviness after the main rail milling has been completed. This avoids the need to use grinding stones for rail finishing. Metal chips are extracted from the site and stored in a bunker on the train.\r\nThe train is built to the W6A loading gauge and is powered by two C18 Caterpillar diesel engines which are certified to the stage 3b European emissions standard and prepared for stage 4.