Braking Questions - Substantiation and explanation for use of the tool for the identicality-check for recertification of LL-blocks

A tool has been developed to be able to assess whether the dry friction behaviour of LL brake blocks under recertification can be considered sufficiently similar to the original approved blocks to state that the blocks are identical. This tool is based on the variation in friction properties of cast iron, and can be applied to LL-blocks in 2xBg and 2xBgu configuration. This document describes the substantiation and development of the tool, and provides a manual for assessors on how to apply the tool.