Mechanical Design & Fabrication of Redressing System for the VT-FRA Roller Rig

At the Center for Vehicle Systems and Safety at Virginia Tech, the Virginia Tech – Federal Railroad Administration Roller Rig is a state of the art facility used in evaluating the wheel-rail mechanics and dynamics of railway vehicle and track. Consisting of an upper wheel, a lower roller, and multiple actuators/servos, the Roller Rig is fitted with sensors that measure different parameters from force, rotation speed, and more. However, while the Roller Rig is a fitting device for a multitude of scientific and engineering studies related to railway vehicles, wheel-rail interaction while the Roller Rig is in operation, creates a rough wear band that is visible both to the naked eye, and on the micron level with the use of laser scanners. With the presence of this wear band, before the start of each experiment, a process known as redressing must be performed to smooth the surface of the wheel. This process is necessary to promote data precision and consistency throughout experiments. Previously, this process was done entirely manually, with the individual wrapping various grades of sandpaper around a common PVC pipe and applying pressure while the Roller Rig’s wheel spins. This is done with a total of 5 grades of sandpaper, varying from 40 grit up to 220 grit. As one can imagine, this process is incredibly labor intensive and presents many concerns related to safety, worker productivity, and overall precision and consistency of the redressing process. This paper will look at the development of a device to perform this redressing process in a semi-automatic, hands-off manner. Through initial brainstorming and concept generation to fabrication methods and manufacturing, this paper looks at the different the Roller Rig Redresser project throughout the entire engineering design process.