The front of the flanger has a "V" shaped plow, that lowers between the rails, but not below the height of the rail head. This first pushes the snow, (or ballast) from the center of the rails, towards the field sides. The wings are next, and some are notched, to actually plow below the level of the railhead. The wings distribute this plowed snow, along with snow from the outside of the rails, to the outer end of the wings. (depends on how far they are opened, to how far the snow is moved) Used to be, crossings had a sign, with the letter "F" on each side of it, in snow territory. This was the warning, for flanger operators, to raise the plow, and the wings. After flanging/plowing, the snow is packed tight, higher than the level of the railhead, by a few inches, and the fields are plowed (hopefully) wider than the steps, of the locos that work in the territory. The things are somewhat light, and do derail with frequency that seems to be planned to keep the guys on the crew, from getting too warm, inside the flanger, or pushers used to move them.