This spring, Cedar Point opened Top Thrill Dragster, the tallest and fastest roller coaster in the world. Instead of a traditional lift hill, the Top Thrill Dragster uses an innovative hydraulic catapult system that accelerates riders from zero to 120 mph in four seconds. Launched coasters like Top Thrill, known for their sensational speed and power, have been around since 1977, but are just now taking off for the sky.

Slow Going

The first blueprint for a launch coaster was fairly simple: It had a straight track with a single loop, and was initially named Shuttle Loop. The Shuttle Loops were perfect for parks that desired a looping coaster, but lacked space for a traditional full-circuit looping coaster. There were a half-dozen built in 1977, three by Anton Schwarzkopf of Germany and three by Arrow Dynamics of Clearfield, Utah.

The Schwarzkopf Shuttle Loops consist of two vertical inclines with a vertical loop, launch track, and a station in between. The train is launched out of the station through a nearly circular vertical loop and up a 70-degree incline. Once its momentum wanes, it falls backwards and repeats the journey, including a trip up the rear incline. This incline was originally considered unnecessary but was added for safety reasons in case the brakes failed.

A magnetic launch system was originally planned for the ride, but the technology wasn’t economical at the time, so a multi-ton flywheel system was the next choice. Unfortunately, this system was also unavailable because ride architects couldn’t find a manufacturer who would provide a sufficient guarantee for the flywheel’s clutch system. Finally, a weight-drop system was substituted. A 40-ton weight located in a tower at the far end of the ride connected to a “pusher” via a clutch and a series of cables. When the weight falls, the pusher rides in a slot between the track’s rails and pushes on the back of the train.

A year later in 1978, Schwarzkopf produced a second version of the Shuttle Loop that incorporated the six-ton flywheel system. While all the Shuttle Loops were popular, riders preferred these later flywheel versions because they had a more powerful launch. Even back in 1977, the front vertical inclines were taller than any other roller coaster in the world.

Gaining Speed

Arrow Dynamics introduced its first launch coaster, the Launched Loop, a modified version of the Schwarzkopf design, adding large electric motors to aggressively push the train off elevated platforms on either side of the loop. The motors, combined with a short drop before the loop, provided enough momentum for the train to reach an equally high platform on the opposite side. An elevator was originally incorporated in the prototype to bring riders to the launch platform instead of climbing eight flights of stairs. However, the elevator was not included on production rides, and the prototype—still operating at Fun Spot in Angola, Ind.—has long since discontinued its elevator.

Nearly a dozen Schwarzkopf Shuttle Loops and eight Arrow Launched Loops were built through 1981, and almost all are still operating. However, for the next 15 years, no new launch roller coasters were built because the challenges with the early models were so great. The most significant issue was the maintenance requirements and the accurate controls necessary to have a consistent launch speed. Today’s more advanced systems have virtually no moving parts and few if any spare-part requirements.

When the magnetic launch systems appeared in the mid 1990s, the launch coasters began to regain momentum. Two different types of magnetic launch systems have been used on roller coasters: linear synchronous motors (LSM) and linear induction motors (LIM). Both of these systems require no moving parts or physical contact, which makes them a very consistent, reliable, and low-maintenance launch system. While both of these systems use high power magnets in a linear arrangement, they work very differently.

LSM launch systems use large magnets permanently mounted on the train, with a second series of magnets along the launch track. Pulsing the launch track magnets in a linear sequence creates the force necessary to launch the train. One disadvantage with LSM systems is the weight of the magnets on the train: a significant amount of energy is needed just to propel their weight. Another problem with LSM systems is that the launch track magnets need to be pulsed at precise intervals. A mis-timed pulse can not only fail to provide thrust but actually slow the train in some situations.

LIM launch systems, which rely on the principal of an eddy current, use simple conductive fins rather than the much heavier fixed magnets of the LSM system. An electrical current is passed through a series of electromagnets, generating a linear traveling magnetic field. Eddy currents that oppose this movement are formed in the train’s conductive fins and these push the train forward ahead of the forward-moving magnetic field. Unlike LSM systems, the timing of the magnets does not need to be precise, so while the magnets are activated sequentially it is done to reduce heat and conserve power.

Magnetic Attraction

Premier Rides of Maryland built the first magnetically launched roller coasters in 1996: the Flight of Fear roller coasters, located at Paramount’s Kings Island in Ohio and Paramount’s Kings Dominion in Virginia. Unlike all previous launch coasters, the Flight of Fear rides use a continuous circuit, allowing for multiple train operation and more riders per hour. The ride layout consists of a straight launch track leading into a disorienting spaghetti ball of twisted track.

In the next year, Premier Rides built four more LIM roller coasters. One design, the Mr. Freeze coasters at Six Flags St. Louis and Six Flags Over Texas, incorporates a few innovative features. By using sliding loading platforms, two trains can operate on a single shuttle track. When one train is running on the track, the other is unloading or loading next to the launch track and ready to slot in. The Mr. Freeze coasters also demonstrate how LIMs can be used beyond the launch track. The track ends in a vertical spike with a second set of LIMs at the end. When the train reaches these LIMs, they boost the seven-ton train vertically to build enough energy to complete the return trip backwards—and surprise the riders.

In 1997, Intamin, a Swiss coaster and ride manufacturer, built the first two launch roller coasters using the LSM system: Superman The Escape at Six Flags Magic Mountain in California and Tower of Terror at Dreamworld in Australia. Both consist of a simple L-shaped layout, launching riders down a horizontal track at 100 mph. The track then turns skyward, with the train coasting up a vertical tower until its momentum ebbs and drops back to the station. While both are very short rides, people in the coasters experience more than six seconds of weightlessness while descending the vertical tower. These rides held the title of the fastest roller coasters for nearly five years.

In 1998, Intamin switched to LIM technology and built the first inverted launched roller coasters. Volcano, the Blast Coaster at Paramount’s Kings Dominion was custom built to use an existing mountain facade that once housed other rides. To demonstrate the power of LIM systems, the train is launched vertically and erupts out of the volcano’s center. Another inverted LIM roller coaster called the Linear Gale, installed at Korakuen Amusement Park in Japan, is a simple U-shaped coaster with two vertical towers. The train is launched forward and backward, climbing higher with each launch until its apex is reached. The Linear Gale was the first in a series of six inverted LIM roller coasters. The front tower in subsequent models was changed to a vertical spiral; in the case of the Wicked Twister at Cedar Point both towers are spirals.

Vekoma, based in the Netherlands, is the only manufacturer other than Intamin to use the LSM system. Starting In 1999, the company built three similar LSM roller coasters resembling the layout of the Flight of Fear—a continuous circuit roller coaster launching into a spaghetti ball. Disney’s Florida and French parks purchased enclosed models called the Rock ‘n’ Roller Coaster and an outdoor model called Superman The Ride at Six Flags Holland in the Netherlands.

Blowing Hot Air

S&S Power blew onto the scene in 2001 with the Thrust Air 2000 ride, which incorporates S&S expertise with compressed air-launched tower rides. Paramount’s Kings Dominion purchased the prototype, dubbing it the Hypersonic XLC. Since compressed air launchers are very efficient and extremely fast, the Hypersonic accelerates zero to 80 mph in just 1.8 seconds. Like many launch roller coasters, the Hypersonic has a 90-degree vertical tower, but in this case, riders crest the tower and drop straight down the other side. Each train is weighed prior to launch and adjustments are made to the air pressure to accommodate for varying rider payload. S&S Power’s second air-launched coaster opened in Japan at Fuji-Q Highlands. Like Hypersonic, Dodonpa hits top speed in just 1.8 seconds. But unlike the Hypersonic, Dodonpa’s top speed is 107 mph, ending Superman The Escape’s and the Tower of Terror’s reign as the world’s fastest roller coasters.

In 2002, Intamin introduced its hydraulic launch system with Knott’s Berry Farm’s Xcelerator. Like the Schwarzkopf Shuttle Loops, a cable pulls the train down the launch track, but unlike Schwarzkopf coasters, hydraulic motors power the Xcelerator’s cable spool. The hydraulic motor’s fluid is forced out of reservoirs using compressed nitrogen gas (rather than typical hydraulic pumps) to get the necessary thrust. Intamin’s second hydraulically launched roller coaster is Cedar Point’s Top Thrill Dragster.

In the last decade, magnetic, compressed-air, and hydraulic launch systems have ushered in a new era of speed for roller coasters: The fastest roller coasters went from 72 mph to 120 mph, and the highest drops from 200 feet to more than 400 feet tall today. These rides are faster, smoother, and more wild than was previously possible even just a decade ago.