Origins of the Vertical Velocity

       Illinois - Vertical Velocity is an inverted steel roller coaster located at Six Flags Great America, near Chicago, Illinois.  Using the name 'Twisted Impulse Coaster' this launched shuttle-style coaster has been running at the Yankee Harbor section of Six Flags Great America (Illinois), since May 18, 2001.  Launched roller coaster rides are modern platforms of roller coaster that have seen increased use in the previous decade.  In place of a traditional chain lift, the launched roller coaster initiates a ride with high amounts of acceleration via one or a series of Linear Induction Motors (LIMs), Linear Synchrous Motors (LSMs), catapaults, or other mechanisms employing hydraulic or pneumatic power.  These are some of the fastest rides in the world.  Launched roller coasters cost more to maintain, but they operate at higher speeds which allows more fun designs.  This roller coaster ride uses a single seven seat car (28-passenger) train, which runs along a 656-foot (200 metre), U-shaped track, incorporating two 185 foot (56 m) vertical spikes.  The forward spike incorporates a twisted spiral, and the rearward spike provides a straight freefall.  The 65-foot (20m) train, propelled by linear induction motors (LIMs), is accelerated in less than four seconds to 70 mph toward the forward tower, before dropping back down through the station house, the platform where the next riders are standing, and up the rearward tower.  The train passes at speed through the station four times per ride.  Then, it is braked by eddy-current braking (also called Foucault currents braking) before being brought into final position at the station by the LIM(s).  According to wikipedia 'Vertical Velocity' is 185-feet tall.  Another website had the height at 150-feet tall.  However, one thing both agree on is that 0-70 mph in less than four seconds is fun.  See also, www.sixflags.com/greatamerica.