Ok, heres a great new way to switch your model train on and off using your brain.
Hitachi have developed a helmet that reads the blood concentration in the brain and detects changes in blood flow. This is useful to detect mental activity and then interpret these signals to control some external device. Users need to remember some sort of mental arithmetic or remember something to trigger the train to switch on and off.
The Hitachi site has a little bit more info as well.