A powered coaster is a track-based amusement ride. Powered coasters use very similar track and trains to roller coasters, however propulsion is provided by an engine or motor located within the train.
Many powered coasters do gain speed on downhills and coast uphill, like roller coasters and alpine coasters. However, some maintain a constant speed throughout the ride.
Almost all powered coasters have one or more electric motors within the train. Electricity is supplied via an extra rail on the track. An outlier is the Skywarp from Skyline Attractions, which has powered tires mounted to the track that make contact with the train at all times.
Italian firm SDC manufactured powered coasters with an internal combustion engine rather than an electric motor. There are three known installations, including the former Dragon Flyer at Camelot Theme Park. Tires underneath the train make contact with a flat surface in the center of the track.
Powered coasters do not require a lift hill or launch and thus can be more compact and low to the ground. Powered coasters rely on turns and helices to create thrills rather than large drops. This lends itself to kiddie and family coasters.