Video narration
What makes a heavy train move-and what brings it to a stop? You're on a passenger train, settling in as it pulls away. A power system sends energy to motors, which turn the wheels and set the cars moving. Some trains use electricity, others fuel; motors may be grouped together or spread through the cars. The rails guide the wheels; a power system turns them. As the train gathers speed, the rails carry its weight and keep it on course. The turning wheels press against the rails, moving the cars forward. You feel the cars follow, but the track isn't what slows you down. Near your stop, brakes act on the wheels, slowing their rotation. The train rolls on briefly, then comes to rest. So what moves and stops it? Powered wheels start your ride; brakes bring it to rest.