Xcelerator

Xcelerator is a steel launched roller coaster that was built by Intamin, and is located at Knott's Berry Farm in Buena Park, California.
The ride.
After the riders have been loaded onto the train at the station, the train is first hooked up to a catch car that is under the train. The train has to move back to hook onto the catch car in order to launch. After 2.3 seconds, the train is released from the catch car, and travels at a speed of from the station. The train then travels over a tower, or top hat element, and after that it travels through a 110 ft over banked turn, and then a 95 ft over banked turn before coming to a smooth stop over magnetic brakes.
Problems.
Sometimes, a train does not have enough speed to make it over the top hat element. If that happens, a train tries to go up the tower, stop, then roll back to the station. This is called a shortshot, and it is part of the ride's design. A shortshot can cause the ride to be closed for a period of time while the ride is reset and tested several times before it can be opened again. Rain, weight, the number of time its launched, the outside temperature, and overheating can cause a shortshot.
Xcelerator will not operate in the rain so that a shortshot does not happen when the launch track is wet. Then the track needs to dry until it is safe to test the roller coaster. This happens so that a shortshot does not happen.