Linear induction motors (LIM)
Alternating magnetic fields shove the train without touching it — the workhorse of many modern launches.
LIM launches use stator coils on the track to create a moving magnetic field. A conductive fin or plate on the train interacts with that field, producing thrust without mechanical contact.
Advantages: no catch car wear in the same way as hydraulics, relatively smooth acceleration tuning, and good for multiple launches per cycle.
Tradeoffs: heavy power draw, fin alignment sensitivity, and heat management on repeated cycles.
If a ride has several moderate launches instead of one huge hill, LIM/LSM is often the reason.