In the final .NET on Track layout, we will use three automatic train switches. The switch is controlled by one NXT motor to move the yellow handle, and one touch sensor to check the actual state. By using this touch sensor, the application is able to ‘read’ the actual state of our switches when starting up. So we don’t need to start up with all the switches in a predefined state. Another advantage is that we can check if the command to change the state of the switch, was successful.