LSM vs LIM Launch Systems: Key Differences

Modern roller coaster launch systems have replaced traditional chain lift hills as the primary way to gain speed on the most thrilling rides. Where a chain lift takes 30 seconds or more to reach the top of a 200-foot hill, modern launches accelerate trains from 0 to 70 mph in less than three seconds. The technology behind these launches falls into several distinct categories, each with engineering trade-offs that affect both the ride sensation and the park’s maintenance budget. Understanding the different systems explains why your favorite launched coaster feels the way it does.

LSM vs LIM: How the Two Launch Systems Actually Compare

Both systems do the same job — hurling a train out of the station without a lift hill — but they get there differently. LSM (Linear Synchronous Motor) uses permanent magnets mounted on the train that sync up with electromagnets in the track, which lets the control system meter acceleration very precisely. LIM (Linear Induction Motor) skips the magnets on the train entirely and instead induces current in a passive metal fin, a simpler setup that’s cheaper to build but gives the control system less fine-grained say over the push.

Neither multi-stage nor reversing launches are exclusive to one system. VelociCoaster is an LSM coaster with two forward launches — 0 to 50 mph out of the station, then a 40-to-70-mph boost in about 2.4 seconds through a tunnel. But LIM can do multi-stage and reversing launches too: Intamin’s classic Impulse Coasters use LIM motors to fire the train back and forth through the station repeatedly, typically three forward launches and two backward ones per ride before the brakes finally catch it. So “forward-and-backward” and “multiple launches” are launch-sequence design choices, not something only LSM can do.

Ride feel is where the two systems tend to diverge more. Because LIM’s induced-current push is less tunable than LSM’s magnet-to-magnet handshake, LIM launches are often described as a shorter, blunter burst — Incredicoaster‘s 0-to-55-mph launch in about four seconds is a good example of that sudden-shove sensation. LSM’s finer control tends to read as a smoother, more sustained push, like VelociCoaster’s two launches. That’s a general tendency riders and enthusiasts report, not a hard rule — plenty of LIM rides feel plenty smooth, and plenty of LSM rides hit hard. For more on how that force translates to what your body actually feels, see our breakdown of launch technology.

On cost and upkeep, the honest answer is that it depends heavily on the specific installation, so it’s hard to declare a universal winner. What’s fair to say: LSM’s precise, software-controlled acceleration (and its ability to help slow a train, not just speed it up) has made it the go-to choice for many of the newest, highest-profile launch coasters. LIM hasn’t gone anywhere, though — it’s still a proven, simpler-to-build system, and it’s still the motor behind some of the most relentless, back-and-forth launch sequences in the industry.

Want a smooth, computer-metered push? LSM is the more common choice on recent high-profile launch coasters.
Want a sudden, abrupt kick instead of a gradual ramp? LIM-launched rides like Incredicoaster still deliver that sensation.
Craving a back-and-forth launch sequence? Intamin’s classic LIM-powered Impulse Coasters fire the train forward and backward repeatedly.
Multi-stage launches (more than one speed boost in a ride) show up on both systems — VelociCoaster’s two LSM launches are one example.
There’s no single “better” system — the right fit depends on the ride experience a park is designing for.

Linear Synchronous Motors (LSM)

LSM launches use a series of electromagnets along the track that precisely control train acceleration. The magnets pull on permanent magnets fixed to the train, with computer-timed pulses delivering smooth, sustained acceleration. LSM systems can also be reversed for braking, which is why launches like Universal’s VelociCoaster can pulse trains forward and backward through the launch zone.

The advantage is precise control and minimal mechanical wear. The disadvantage is high energy demand and complex control systems that require specialized maintenance.

According to technical documentation on LSM systems, the technology was first applied to roller coasters in the late 1990s and has since become dominant for new launched installations.

Linear Induction Motors (LIM)

LIM systems work on similar electromagnetic principles but generate force by inducing currents in a metal fin attached to the train, rather than acting on permanent magnets. LIM launches typically deliver shorter, more aggressive acceleration than LSM, producing the punchy “kick” that older launches like California Screamin’ (now Incredicoaster) at Disney California Adventure deliver.

LIM systems are simpler and cheaper than LSM but less efficient and harder to control precisely.

For more on how launch G-forces affect your body, our breakdown of how roller coaster G-forces affect your body explains the physiological response to sudden acceleration.

Hydraulic Launches

Intamin’s hydraulic launches power coasters like Top Thrill 2 (formerly Top Thrill Dragster) and Kingda Ka. The system uses a massive cable winch driven by hydraulic motors, capable of accelerating trains to 120 mph in under 4 seconds. The brutal acceleration produces some of the most intense launch sensations in the industry.

The downside is reliability. Hydraulic launch systems have suffered notable mechanical failures, including the cable incident that closed Top Thrill Dragster from 2021 until its 2024 rebuild as Top Thrill 2.

Compressed Air Launches

Premier Rides’ air launch system uses a piston driven by compressed air to accelerate trains. The technology produces extremely fast launches with low maintenance compared to hydraulic systems, powering rides like Maverick at Cedar Point and Stealth at Thorpe Park in the UK.

Air launches typically deliver faster initial acceleration than electromagnetic systems but lower top speeds.

Industry coverage at Coaster101 notes that air launches have become increasingly favored for mid-sized installations because they balance thrill with maintenance costs better than hydraulic alternatives.

Friction Wheel Launches

The original launch system used spinning rubber wheels to grip and accelerate trains. While dated by modern standards, friction wheel launches still operate on rides like Rock ‘n’ Roller Coaster at Disney’s Hollywood Studios. The systems are simple and reliable but limited to relatively modest top speeds (60 mph or less).

Why Launch Systems Matter to Riders

The launch system on your favorite coaster determines not just top speed but the character of the experience — the smoothness of acceleration, the punch of the initial kick, and even the sound the ride makes. As LSM systems become more affordable, expect them to displace older technologies on most new installations through the 2030s.

For more on how launches fit into the broader coaster category landscape, our piece on every type of roller coaster explained covers how launches differ from chain lifts, gravity drops, and other ride classifications.

Frequently Asked Questions

What is the fastest launch system?

Hydraulic launches like Intamin’s system on Top Thrill 2 deliver the fastest absolute speeds, exceeding 120 mph on the most extreme installations.

How does an LSM launch work?

Linear Synchronous Motors use a series of electromagnets along the track that act on permanent magnets fixed to the train, providing precise, computer-controlled acceleration.

Are launched coasters safer than chain lifts?

Both are extremely safe when properly maintained. Launches have different failure modes than chain lifts but no significantly higher accident rate.

Why do some launches go backwards?

LSM systems are reversible, allowing rides like VelociCoaster to pulse trains forward and backward. Hydraulic and friction wheel launches generally cannot reverse direction.

How long does a typical coaster launch last?

Most launches last 2 to 5 seconds depending on target speed, with hydraulic systems delivering the shortest, most aggressive acceleration profiles.

Which feels more intense, an LSM or LIM launch?

LIM launches are often described as punchier and more abrupt, like Incredicoaster’s 0-to-55-mph launch in about four seconds. LSM launches, like VelociCoaster’s 40-to-70-mph boost in 2.4 seconds, tend to feel more like a sustained, controlled push — though individual rides vary.

Is LSM or LIM the better choice for a first-time rider?

LSM’s smoother, more metered acceleration is often seen as the gentler introduction. LIM’s more abrupt kick can catch first-timers off guard, though this varies ride to ride.

Will LIM launches eventually disappear from theme parks?

Not likely anytime soon. LSM has become the preferred system for many new high-profile coasters because of its precise control, but LIM remains a proven, simpler technology that still powers plenty of rides, including multi-launch coasters like Intamin’s Impulse models.

Which launch system should a park choose for a new coaster today?

It depends on the experience they’re building. LSM’s fine-tuned control suits smooth, repeatable multi-launch show coasters, while LIM remains a simpler, lower-component option that still delivers dramatic, back-and-forth launch sequences like those on Intamin’s Impulse coasters.