Sector project "BB-Wheel Interaction" - WP1/Activity 1.3: "Assessment of the brake heterogeneity” - Activity report

"Brake Block Wheel interaction” is a sector project involving Brake block manufacturers, Entities in charge of wagon maintenance, Railway Undertakings, UIC Staff, Universities, Wagon keepers and Wheel Manufacturers.

Its goal is to define the appropriate conditions for managing brake block/wheel interaction avoiding safety risks and restrictions in the use of tread-braked wheels, improving the reliability of the system, and improving and harmonising rules to prevent approaches based on singular experience.

The sector project is structured in three major work packages:

§   WP1 “Analysis of the state of the art, calculations and tests specifications”

§   WP2 “Calculations, laboratory and field tests”

§   WP3 “Summary of the results”

WP1 is articulated in four activities:

§   WP1/Activity 1.1 “Influence of the operational conditions on wheel design”

§   WP1/Activity 1.2 “Wheel design worst case scenario assessment”

§   WP1/Activity 1.3 “Braking heterogeneity assessment”

§   WP1/Activity 1.4 “Brake block characteristics - impact on energy distribution”

The specific tasks to be managed were:

§   a statistical study on the composition of the freight trains operated in Europe, depending on the types of the conveyed wagons, their braking equipment, the value of coefficient of frictions of the different types of brake blocks.

§   the assessment of the variation of the brake rigging efficiency during the life cycle of the wagons.

§   the assessment of the distribution of the braking power along freight trains, depending on the train configuration (distribution of G-braked and P-braked train, wagon loading conditions, number and position of the unbraked wagons), the brake rigging efficiency, the applied braking forces, the types of brake blocks.

The objective was to provide:

§   a clear definition of brake heterogeneity

§   the list of the parameters having impact on the energy distribution along freight trains,

§   the results of the enquiry carried out to assess how these parameters affect the European wagon fleet,

§   requirements to make measurement to assess the efficiency of the brake rigging during the life cycle of the wagon, proposals and requirements for numerical simulations, test benches, field tests to be performed in the framework of WP2.