The British prototype Advanced Passenger Train (APT) used hydraulic retarders to allow the high-speed train to stop in the same distance as standard lower speed trains, as a pure friction-based system was not viable. Retarders are not restricted to road motor vehicles, but may also be used in railway systems. For this reason, such heavy vehicles are frequently fitted with a supplementary system that is not friction-based. As the friction brake will be used less, particularly at higher speeds, their service life is increased, and since in those vehicles the brakes are air-actuated helps to conserve air pressure too.įriction-based braking systems are susceptible to ' brake fade' when used extensively for continuous periods, which can be dangerous if braking performance drops below what is required to stop the vehicle – for instance if a truck or bus is descending a long decline. They are usually used as an additional 'assistance' to slow vehicles, with the final braking done by a conventional friction braking system. They are not usually capable of bringing vehicles to a standstill, as their effectiveness diminishes as vehicle speed lowers. Retarders serve to slow vehicles, or maintain a steady speed while traveling down a hill, and help prevent the vehicle from 'running away' by accelerating down the hill.

Torque converter, opened, interior similar to a retarderĪ retarder is a device used to augment or replace some of the functions of primary friction-based braking systems, usually on heavy vehicles.

Controller remapping bus simulator 18