Not quite. Each train has an encoder to transmit the states of each individual component and, as you said, a photo eye beam system, however the ride PLCs (programmable logic controllers, these are the brains of the ride) are located behind the door at the front of the left-hand loading station if memory serves me right. But the PLCs themselves are honestly probably in good enough knick to last the ride through to demolition. Every ride experiences faults with PLCs - even new ones - so new PLCs invariably will not stop the occasional emergency stop.each train has its own PLC (If I recall correctly) and they may have to have new PLC on the train
Where the ride suffers are aborted sends. This is when the ride detects an anomaly in the dispatch sequence and halts the dispatch of a train. This is often because a sensor reports an incorrect reading with a harness and changes state partway through tilt. If you find yourself stopped mid-tilt and brought back down, this is often the cause. New sensors, and possibly encoders, are what are needed.