Roller coasters have different types of brakes in the middle of a ride. Mid-course block brakes allow a train to be brought to a complete stop if preceding train has not cleared the next section of track. These brakes, usually a large set of brakes, are built at a height high enough to allow the train to resume the course and coast to the station. These block brakes also typically have stairs and a platform to allow riders to be evacuated off the train, but that feature is seldom used.
On the other hand, trim brakes are used to just slow the train, not stop the train. Often just one or two sets of brakes, trims help bleed excessive speed from the train as it passes by. On most modern coasters, the train's speed is measured by proximity sensors and the amount to pressure applied to the trims is modulated to set the train's speed after it passes the trim brakes.
On the way up this 141-foot hill shown in the center of the picture, trains on Raging Bull pass these two sets of pinch brakes which serve as trims. Just below you can barely make out the two green squares that are the proximity sensors which use magnatism to sense the passage of the train.
©2013 by Joel A. Rogers.