Refined Test Procedure for the Parking Brake of Freight Cars

Purpose: A refined test procedure for the parking brake of freight cars is described, which simultaneously satisfies the requirements of two regulatory documents: GOST 26686-96, which establishes the moment applied to the handle (steering wheel) of the parking brake, not more than 300 N, at which a single freestanding loaded car on a slope of at least 30‰ must be retained, and GOST 34434-2018, which sets the design (test) moment of force applied to the parking brake handle at 100 N∙m. Methods: Stage-by-stage processing of test results is carried out: initially, the average values of pressing force and the actual pressing force on a single brake block is determined. Then the coefficient of friction between the blocks and the wheel and the maximum slope of the track, on which the railway rolling stock is retained by the parking brake, are calculated. The solution of the problem is based on the iteration method, which must be applied twice: at the first stage, in order to find the value of the total pressing force on the brake blocks from the action of the parking brake, taking into account that the maximum slope of the track, on which the train is retained by the parking brake, equals 30‰, then at the second stage, such a value of the moment on the parking brake drive shaft is selected so that the value of the required pressing force on the brake blocks from the action of the parking brake is the same as with the maximum slope of the track id = 30 ‰, after which the obtained results are evaluated and compared with the normative values. Results: An updated method for testing the parking brake of freight cars has been developed. Practical significance: The application of this technique will allow taking into account the requirements of two regulatory documents at the same time preventing their contradiction.