Smart tech is the new train technology from Brio! simply press go on the engine and set up the smart tech arches around the track. The engine will automatically detect each arch and do exactly what is shown. It could stop, start, go slow, turn on the lights or make a sound. Isn't that fun. Choo-choo! the locomotives are more alive than ever. Depending on the tunnels, the engine will stop, back up or blink its lights. The engine w action tunnels Starter kit is based on interactive smart technology that sets you off on your travels, and you are the decision maker! includes 1x smart engine, 2x smart tunnels.