Yellow Light
Each amusement park ride in ̶0;RollerCoaster Tycoon 3̶1; is equipped with a stop light that displays in which stage a ride is in currently. A yellow light indicates that a park's ride is either in need of repair or it is queued to start. When the ride is queued to start, all of the passengers have boarded. When the ride is full and the tracks are clear, the ride will start. The stoplight will turn green when it starts.
Repair
When a ride is in need of maintenance, its stop light will either turn red or yellow. If the reason for the repair is not because of a crash, it will be yellow. You can double-click the yellow light to call the nearest mechanic to the scene. If the mechanic is taking too long to respond, you can click on a mechanic and assign him to repair the park ride. Once the repair is complete, the ride will open again and passengers can once again board it.
Queued Rides
A queued ride in ̶0;RollerCoaster Tycoon 3̶1; means the ride is full of passengers and ready to go. The only hindrance to its departure is another cart on the tracks. The rides are designed to take into concern the safety of the passengers and wait for clearance to safely proceed without the danger of running into another cart. The entire process is automatic and does not require you to start and stop cars.
Other Lights
If a red light is displayed on your ride, it is in serious need of repair. Double-click the red light to send a mechanic to the scene immediately. The light is also displayed if you manually turned off the ride. Customers will bypass the ride until the light is green. A green light signals to customers that the ride is operational and tickets are available to ride it.