Load deceleration

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Representation of a manual load change. If the total weight of the wagon reaches or exceeds the stated conversion weight, the load change must be set to "loaded".

Cart, in which the gross weight is significantly greater than the empty weight , are provided with a load-proportional equipped. This device enables the brake pad pressure to be adapted to the effective weight of the vehicle. It prevents overbraking when the load is low and counteracts insufficient braking force when vehicles are loaded. If the vehicle weight increases due to the load while the braking force remains the same, the braking effect is reduced. This becomes more noticeable the lower the curb weight and the greater the payload.

There are various options for braking the load with both the compressed air brake and the suction air brake . A distinction is made here between load changes - which change manually or automatically - between defined positions, and automatic load braking, the braking force of which is adjusted continuously and always automatically.

Manual two-stage load change of a freight wagon in the empty position . From a total vehicle weight of 44 t, the load change to Bel. (Loading) to convert.

The brake pad pressure is changed by hand when the load is changed manually. These are available as two-stage load changes with the positions “empty” and “loaded” and as three or multi-stage load changes with the positions “empty” and several positions “loaded”. In the case of cars with more than one control valve or brake cylinder, there can also be more than one load change. It is precisely the purely mechanical load changes that have to be built into each independent brake linkage, since these work their braking force by changing the force triangle in the brake linkage. There are also systems in which an additional brake cylinder is switched on.

Address of the automatic load change on a freight wagon. From a total vehicle weight (vehicle weight + load) greater than 22 t, the brake automatically switches to loaded. This can be checked with the help of the monitoring display.

With the automatic load change , the changeover takes place automatically between the positions. Depending on the system, this can only consist of “empty” and “loaded” or, more rarely, also include several intermediate stages. The automatic load changes are mainly found in freight wagons that are either fully loaded or empty (e.g. tank wagons).

Address of the automatic load braking on the side member of a freight wagon. A maximum braked weight of 56 t can be achieved. The maximum braked weight of 56 t is the sum of the weight of the wagon and the load. With a dead weight of 27 t and no load, the braked weight is 27 t. With a load of z. B. 10 t a braked weight of 37 t. With a load of z. B. 29 t a braked weight of 56 t. With further loading, the braked weight does not increase any further.

In addition, there is also the continuously acting automatic load braking, which increases continuously to the measured vehicle weight up to a certain braked weight. Recognizable by the -A of the brake address (example "Brake O - GP - A Max. 23 t.").

With both automatic systems, the weight can be recorded via one (or more) measuring cells (pneumatically operated) or via a mechanical weighing device (in the manner of an inclination scale ). With the mechanical weighing device, a different torque acts on an angle lever - due to the different car weights - against a spring. Due to the resulting twisting and the resulting changes in length of the attached rod, this can be used as a mechanical drive to adjust the pressure booster on the control valve.

literature

  • Directive 915.01 of the DB AG

Individual references, comments

  1. ↑ Frank Minde: Fundamentals of Railway Brake Technology (PDF; 144 kB). Minden (Westphalia), 2007
  2. ↑ SBB R 450.2 Volume 2 Issue 84 (regulations repealed)
  3. ↑ Addresses and symbols on freight wagons ( Memento from March 4, 2016 in the Internet Archive ) AVV Annex 11 Chapter 4.3.7 PDF page 44
  4. ↑ SBB R 450.2 Volume 2 Booklet 85 (regulations repealed)