Vibroacoustic study of circular cylindrical tubes in roller coaster rails

Excessive noise generated by roller coasters during operation is a significant issue for amusement parks located near residential and business districts. Previous work showed that filling the rails with sand and pea gravel can provide noise reduction levels of up to 10 and 15 decibels. However, using damping materials may require additional support structures to accommodate the weight increase and, consequently, raise installation costs. This paper presents field results that characterize sound and vibration of roller coasters with different rail geometry and fill. Finite element modeling is used to compute the theoretical natural frequencies and mode shapes of a typical track section. Additionally, laboratory experimental results of lighter fill materials are presented. The results indicate that vermiculite provides similar, though less noise reduction than sand, but with a much lower additional weight. Furthermore, the handling and manufacturing characteristics are superior to the other materials investigated.