Bobs

(from the article `roller coaster`) ...track height to 72 feet (22 metres), but the Fireball was one of the first coasters to circumvent this law by ending the first drop in a man-made ...
Found on http://www.britannica.com/eb/a-z/b/83

bobs

knobs, or small polished wheels of solid felt or leather with rounded edges.
Found on https://www.cliffsnotes.com/literature/m/my-aacutentonia/study-help/full-gl
No exact match found