As can be imagined, cleaning ballast can be a dirty, grimy job as seen here as UP No. 902053 undercutter works at McGrew, Nebraska, on July 26, 2009. Workers constantly watch the machine for problems, and with the incredible amount of moving parts, there is plenty to watch! This includes making sure the cutting depth doesn’t interfere with culverts and other underground obstructions. In this view, the foreman controls some of the functions of the Plasser & Theurer RM 2003 undercutter with a control box on a swinging arm. Why clean ballast? Over time, ballast can break down, and other impurities like sand and dirt can further create drainage problems in the track structure. This machine excavates under the track to various depths, with a series of conveyers taking the “dirty” ballast through screens, sorting out the fines and contaminants from good ballast, and depositing the “cleaned” ballast back onto the track with a oscillating return conveyor and distribution plow. The waste materials are discharged using conveyors that deposit the material to either side of the right-of-way, or into open-top railcars.
