Roller skating is the traveling on surfaces with roller skates. It is held by a stainless steel shaft with roller bearings. Elastomeric bearings may also be used in place of conventional roller bearings. Wendy took on the night of the roller coaster crash. This listing contains all types of roller coaster inversions. The flagship attraction is "Harry Potter and the Escape from Gringotts" roller coaster ride. The EP contains five tracks including the title track "Roller Coaster". She is a casualty in the Devil's Flight roller coaster derailment. Another improvement was use of a hydraulic lifter/roller camshaft on most 1987 LG4s. Power was transmitted by means of two roller chains to the rear axle. The 1987 versions had and more and a change to hydraulic roller camshaft. Pignati gives each of the two a pair of roller skates. A slipper type torque wrench consists of a roller and cam (or similar) mechanism. Drive tires are often used in one of two ways on roller coasters. There are three basic switch designs for roller coasters.