Rollercoaster Jumps Tracks At Fair 3/13/06 6PM Joel Waldman MIAMI A popular ride at the Miami-Dade County Fair and Exposition, which opens later this week, is being dismantled and removed today after five people were hurt during a test ride failure on Sunday. The injured people were testing the Mark 1 roller coaster, a 40 foot high steel coaster with a top speed of 25 miles per hour. Miami-Dade Fire Rescue spokesman Lt. Roman Bas says two people were airlifted to Ryder Trauma Center, and two others with less serious injuries were taken by ambulance to nearby hospitals. All but one of the people injured was released fom the hospital by Sunday night. The coaster is operated by Conklin Shows, which has the midway concession at the fair run by Miami-Dade county. An investigation is underway to determine exactly what happened.