Dowty retarder
As Dowty retarder (also piston Klein brake ) are stationary mounted brake elements in the track referred to the above-propelled freight cars to a predetermined steady speed down brake. This type of track brake was named after the developer George Dowty , who developed this type in the 1960s.
functionality
Each individual retarder consists of a small cylinder filled with hydraulic oil in which the brake piston moves. The brake is triggered by the flange of the wheel rolling over it and is similar to a screw brakespeed dependent. The preset response speed determines the damping of the piston through controlled escape of the oil through small or large bores. As a result, each individual retarder performs a work or an idle stroke automatically and without external energy supply. Since each individual brake pad can only perform a braking work of 1.25 kJ, these must be arranged over the entire deceleration distance at short intervals of less than one meter. To avoid damage, the retarders may only be driven on at a maximum speed of 10 km / h.
To enable the braking effect to be switched off for poorly running cars or maneuvering journeys , the retarders can be grouped together on bars that can be folded down without a profile . A further development of the Dowty-Retarder is the so-called Dowty-Booster , which also allows acceleration through an active control. Immediately after passing the wheel, the ram is lifted hydraulically and thereby the wheel is pushed. This variant is occasionally used to make the drainage hill lower and to avoid problems with poorly running trolleys.
Applications
Dowty retarders are used, among other things, in marshalling yards with free drainage as slope compensation brakes . In the Nuremberg marshalling yard, for example, they are used to automatically slow down wagons in the directional tracks to 1 m / s (3.6 km / h). At this speed, newly arriving wagons collide with those that are already waiting, without damaging the wagon or load. In Austria the system is used in the central marshalling yard in Vienna-Kledering.
Individual evidence
- ↑ cf. also en: Dowty Group
- ^ Ultra Railway Products. Ultra Dynamics , archived from the original on October 3, 2011 ; accessed on June 26, 2011 (English).
- ↑ a b Jörn Pachl : System technology of rail traffic , planning, controlling and securing rail operations, Wiesbaden: Vieweg + Teubner 2003, ISBN 978-3-8351-0191-3 , p. 280
- ↑ a b DB Cargo branch Nuremberg, DB Museum Nuremberg, History For All eV (Ed.): 100 years of the Nuremberg marshalling yard . Nuremberg: Sandberg Verlag 2003, ISBN 3-930699-36-2 , p. 49