A tilting train is a type of train that can travel faster than ordinary trains because it tilts when the track curves.
tilting train in British English
(ˈtɪltɪŋ treɪn) or tilter
noun
a train designed to tilt when going round bends to compensate for the G-force push experienced by passengers. In a curve to the right the train tilts to the right, and vice versa