How to Choose a Roller Coaster System and the Role of Hydraulics

Roller Coaster Safety

Many components we've listed above serve to keep riders safe, but passengers don't interact with those components. Instead, they see safety features like harnesses and seat belts. These keep riders secure in their seats at launch, throughout the journey and until it's time to exit the ride.

The restraint bars on a roller coaster keep riders secure. Whether they are lap or shoulder bars, they need a reliable mechanism to lock them in place and unlock them once the ride is over. Roller coaster safety features may use:

• Mechanical systems
• Hydraulic systems
• A combination of mechanical and hydraulic technologies

These systems lower and raise safety bars, so they must function well, no matter how many safety mechanisms a roller coaster uses. Depending on the construction of the ride, a car may have multiple security devices. Roller coasters with extreme twists and turns or upside-down loops require more secure harnesses. If there is any risk that lifts riders out of their seat, shoulder harnesses are the right choice. A ride will also need secure harnesses and bars if a roller coaster has a rapid and powerful launch.

Roller Coaster Launch Systems

It's one of the most thrilling parts of a roller coaster ride — the launch. Launch systems give riders a boost before the rest of their exciting journey. There isn't just one type of roller coaster launch system because different rides require different launch equipment. The right system for a given coaster depends on how fast the ride launches passengers, the amount of space there is for the equipment and other factors. Different types of launch equipment include:

• Electromagnet
• Hydraulic
• Pneumatic
• Flywheel
• Catapult
• Friction wheel

The type of system describes the mechanical process or component that launches the train car. Every system operates differently with varying results. The last three systems — flywheel, catapult and friction wheel— are the least common varieties of roller coaster launch systems. They are less common choices because they tend to use more energy than the other three options. They also work in different ways:

1. Flywheel: A flywheel is a device that stores rotational energy as it spins at high speeds. That energy, when attached to a cable and roller coaster car, helps pull the train forward.
2. Catapult: A diesel engine or a dropped weight wind a cable. The cable then pulls the roller coaster cars until they reach their full speed.
3. Friction wheel: Horizontal wheels lie under the roller coaster train. Wheels on either side of a metal fin under the car spin in opposite directions, propelling the car forward.

These various systems use physics in different ways to get roller coasters moving. Roller coaster engineers do not use them as often as other varieties because they do not produce as much power. The power that they do create is not considered efficient either because they require a lot of energy to operate. The ratio between the power they need and what they provide does not make them the best roller coaster systems out there.

The three more popular launch systems use forces and equipment that are a bit more complex. Narrow down your choices by comparing pneumatic, hydraulic and electromagnetic roller coaster launch systems.

Pneumatic Vs. Hydraulic Vs. Electromagnetic Roller Coaster Launch Systems

These standard roller coaster launch systems propel roller coaster trains forward as the ride begins in various ways. In general, they work as follows:

1. Electromagnets: Electrical impulses react with magnetic fins on the bottom of train cars. These impulses either attract the fin or repel it, causing it to stop or move forward on the tracks. The launch system uses stator and rotor components to create a linear force that achieves propulsion. Engineers select this option when they want to control speed precisely. An electromagnetic roller coaster launch system produces higher acceleration at the start, which eventually dies down throughout the rest of the launch.
2. Hydraulic: In a hydraulic system, a sled connects to the roller coaster train via a cable. As the hydraulic motor functions, the cable winds around a drum, which pulls the sled. The sled then releases the train, slows down and heads back to its starting spot. The motor uses incompressible hydraulic fluid in one compartment as it compresses nitrogen gas in another. The power generated throughout this process goes to the cable drum to wind the sled's cable. Engineers choose hydraulic options when they want faster and smoother acceleration, especially compared to an electromagnetic system. Some designs have more moving parts than an electromagnetic system, which can sometimes impact reliability.
3. Pneumatic: A pneumatic system functions similarly to a hydraulic one. The primary difference between the two is that pneumatic launch systems replace nitrogen gas and hydraulic fluid with air. While these systems provide a constant acceleration, the loud noise they produce is a turn off for theme parks and guests. With their loud noise comes less powerful propulsion.

The most common launch systems are popular for a reason. They each come with their own strengths but, as with any mechanical system, there are the occasional drawbacks. Certain varieties within these different launch mechanism categories have their positives and negatives.

As we've described above, an electromagnetic system uses forces of repulsion and attraction to launch a roller coaster. There are two different options under this category:

1. Linear induction motors (LIM): Sets of magnets with a gap in between them propel trains forward as a fin under the train passes through the gap. Currents applied to the magnets on the track create a magnetic field to affect the fin.
2. Linear synchronous motors (LSM): This system uses rare earth magnets attached to the train car to repel or attract the train to electromagnets on the track. This system uses computers to reverse the magnets on the track as necessary.

Either variety of electromagnetic propulsion will produce a smooth launch. But no matter which electromagnetic system you choose, you'll need a lot of energy to run them. Variations between pneumatic and hydraulic mechanisms depend on where you get your equipment.

Any roller coaster launch system requires power to operate. It's just a matter of how much they use compared to how much they yield. You should compare pneumatic, hydraulic and electromagnetic launch systems as you choose a mechanical setup for a roller coaster.