Mostly incorrect. The trim brake definition you use was told in old tv shows, but in reality, trim brakes can be placed anywhere.
In the case of TRON, the ride use two kinds of brakes, pusher tires to move the trains around the stations, pre launch and after final slow. Linear Synchronous Motors (LSM) launch the trains. a departure from earlier Vekoma Motorbike Coaster that used an hydraulic launch system connected to a cable and sled that attached to the train.
On each train, permanent magnets are mounted in pairs under the cars. When in the launch section, LSM's are mounted to go in between the magnets, with this effect: when launching the train: the LSM's change polarity rapidly, repulsing the magnets mounted on the cars, which in effect launch the train. One unique trick that Vekoma programmed into TRON: the last section of LSM's is programmed to give a last second "oomph", to simulate a motorcycle changing gear and accelerating. What happens if the launch misfires? The train rolls backward out of the first high curve and the LSM's in their natural state will slow the train down until it returns to the launch position.
Once the train hits the first block brake, high in the air after going outside, metal fins are mounted on the block brake and placed to slow the train down smoothly and silently. Some of the metal fins are mounted on pneumatic cylinders to move in and out of the way depending on what amount of braking is required.
As the magnetic brakes and fins can't stop a train, at the launch start, on the block brakes, stations and where a train needs to stop, traditional pneumatic brakes are mounted, which grabs a metal fin placed under each car in the middle. The pair of pusher tires also grab that fin. Going back to the misfire and train rolling backward into the launch area scenario, pneumatic brakes are placed in sufficient amount to stop the train. Also, the next train can't enter the launch position until the previous train has cleared the first high curve.
Roller Coaster Dream from China posted this great track nerd video where the camera is pointed at the track with a light, showing all the hidden mechanics. I had the chance to do a backstage tour during IAAPA Asia Expo last year at Shanghai Disneyland and my group went behind the scenes at TRON.