A tilting train is a train that has a mechanism enabling increased speed on regular rail tracks. As a train (or other vehicle) 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. 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 (passive tilt), or it may have a computer-controlled powered mechanism (active tilt).
The first passive tilting car design was built in the US in 1937, and an improved version was built in 1939. The beginning of World War II ended development. Talgo introduced a version based on their articulated bogie design in 1950s, and this concept was used on a number of commercial services. Among these was the UAC TurboTrain, which