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How to use it
Enter mass, initial speed and gradient, then the force on each block or pad, their number and the friction coefficient. You get the braking force at the wheels, the deceleration, the stopping distance and time, the adhesion used and the energy to be dissipated. With the parking brake data you also get the maximum gradient held.
Formulas used
Limits
The calculation uses a constant mean friction and a braking force that builds up after the response time. It does not derive the block force from the brake rigging and cylinder, nor the braked weight and the braked weight percentage, which are determined with the method of the applicable standard and by tests.
FAQ
Why is the adhesion used checked?
If the braking force exceeds what the wheel can transmit to the rail, the wheel locks and develops flats. For block brakes one normally stays below 0.15.
What friction should be used for the blocks?
It depends on the material: cast iron blocks have a friction that rises sharply at low speeds, composite ones are more constant. For a first calculation a mean value between 0.15 and 0.25 is used.