Overview
Braking performance can be expressed via a braked weight or via decelerations. This is scope o the UIC Leaflet 544-1 Brakes - Braking performance. The leaflet details the conversion of the braked weight to the braked weight percentage of a vehicle or train for operating purposes. Reference is also made to limiting features arising during operational application of the braked weight percentage of a train calculated from the vehicles' specified braked weight, for different train formations.
Braking performance is defined based on a number of standardised conditions (e.g. gradient) and a mean in-service vehicle condition. Brake assessment thus currently does not assume the worst possible vehicle condition, which may be the result of e.g. braking force tolerances, friction coefficient scatter, downgraded efficiency etc. It led to the conclusion to update UIC leaflet on Brakes and Braking performance.
Update UIC Leaflet 544-1 Brakes - Braking performance.
Funding
Results
Updated UIC Leaflet 544-1 Brakes - Braking performance.
This leaflet defines braking performance and describes the method for determining the braking performance of railway vehicles and trains.
Currently there is 6th version of the leaflet and last modification was done on November 2014.
Innovation aspects
By default the brake assessment is made using the brake position "P". However, the leaflet also indicates reference values for stopping distances which can be obtained in the brake position "G". The assessment curves are presented as graphs and in mathematical terms.
Technical Implications
The assessment in the shape of a braked weight is valid for trains and individual vehicles at speeds up to 200 km/h. Assessment via decelerations is valid only for trains, though irrespective of speed.
The leaflet provides pointers for calculating the performance of the screw brake with hand wheel and the spring-loaded brake.
Readiness
Up to date leaflet can be downloaded (6th edition, 147 pages):
https://www.uic.org/etf/codex/codex-detail.php?langue_fiche=E&codeFiche=544-1
Price is 915 Euros.