A tilting train is a train that has a mechanism enabling increased speed on regular rail tracks. As a train rounds a curve at speed, objects inside the train experience centrifugal force. This can cause packages to slide about or seated passengers to feel squashed by the outboard armrest, and standing passengers to lose their balance, or in such excessive speeds, could even cause the train to derail. Tilting trains are designed to counteract this by tilting the carriages towards the inside of the curve, thus compensating for the g-force. The train may be constructed such that inertial forces cause the tilting, or it may have a computer-controlled powered mechanism.

The pendulum car was an experimental tilting coach built by the Pacific Railway Equipment Company (PERC) in the early 1940s. It used an innovative coiled spring suspension system that allowed the cars to lean into curves, thus increasing passenger comfort during high speed travel. PERC built three cars which were tested on American railroads throughout the 1940s, but the advent of World War II, and their high cost relative to conventional equipment, prevented their wider adoption.