The pendulum car was developed to satisfy these track restrictions, and has a built-in car body tilting device for the bogie, tilting the car body further into curves, thereby reducing lateral constant acceleration and increasing the speed along curves without sacrificing comfort.
5.2 Pendulum Car Composition
Looking at pendulum cars in terms of car body tilting system, they can be divided into:
(1) Those with a natural pendulum system in which the car body is supported by pneumatic springs attached to the roller device and at high locations, tilting the car body naturally into the curve due to the centrifugal force produced when negotiating curves.
(2) Those with a forced pendulum system in which the car body supported by link or other mechanisms is tilted into the curve by force with hydraulic cylinders.
Examples of the former system include the Series 381 in Japan and TALGO in Spain, and of the latter, the Series 8000 in Japan (JR Shikoku) and the ETR450 in Italy.
Looking at pendulum cars in terms of composition of the car body tilting device and car body support bolster springs which affect the riding comfort of the pendulum car, they can be divided into:
(1) Those with "inter-spring pendulums" placing bolster springs above car body tilting devices such as links and rollers, as with the Series 381 and many other pendulum trains.
(2) Those with "sprung pendulums" placing bolster springs below car body tilting devices, as with the ETR450 in Italy.
5.3 Pendulum Cars in Japan
5.3.1 Series 381 Roller Type Natural Pendulum Car
The bogies of this train are fitted with roller type pendulum devices consisting of a pair of roller devices and a pendulum beam which rolls on rollers with a protruding rolling board below (the car body tilting center is a high 2300 mm above the rail surface due to the natural pendulum). The centrifugal force when traveling along curves causes the car body to tilt into the curve up to 5｡?llowing curves to be negotiated 15 - 20 km/h above or below the speed restriction.
