A Brake section is a special track feature, available on most roller coasters and some other tracked rides, that slows all trains passing over the section down to a preset speed. Brakes are also present in all ride stations (though these can sometimes fail, often resulting in a crash). Brakes used outside the station can be used to reduce ride intensity or to prevent the trains from entering the station at high speeds, thus preventing crashes due to station brake failures. Ride builders must exercise caution when building brakes, as slowing trains down too much may result in the train failing to complete the ride.
RollerCoaster Tycoon 2 introduced Block Brakes, which were not present in the original game but are present on many real-life roller coasters. Block brakes, along with their operating mode, 'Block Section Continuous Circuit mode' set a roller coaster to utilize block brakes.
Block brakes are used to create 'sections' of a particular ride, with each section allowed to hold no more than one train at a time. This feature can be used to prevent, or even eliminate, the chance of a ride crash, either due to brake failures in the station or due to a train stalling out or not completing a circuit. Rides running in Block Section Continuous Circuit Mode treat the first tile of the station and the last tile of any lift hill as a block brake by default. Rides operating in this mode may carry more trains than would fit in the station, since the station now only needs to be long enough to accommodate a single train. The maximum number of trains on a ride with block brakes is one fewer than the number of block brakes on the ride (including the top of all lift hills and the station). Therefore, a ride running with one station and one lift hill in Block Section Continuous Circuit Mode could only run one train.
Block brake sections in all cases will slow a passing train down. If the section immediately following the brake is free of trains, the block brake will allow the train to pass, albeit at a very slow speed (~4 mph). If, however, the section following a brake is occupied by a train, the brake will hold the passing train in place until the section is cleared.
The use of block brakes complicates the construction of rides. Timing the length of each ride section becomes crucial, to prevent trains from being held up at block brakes for too long. Preferably, a ride should be able to run a complete circuit without being stopped by a block brake, if the ride is well-designed and nothing has happened on the ride (such as a breakdown) to alter the timing of the ride. Additionally, care must be taken on the placement of block brakes, as block brakes will slow down a passing train to a very slow speed. Despite these complications, in most cases it is preferable to build a ride with block brakes, as block brakes reduce the chances of a ride crash.