Page 1 of 6 TITLE MINIMUM BRAKE PERFORMANCE OF DISC BRAKED WAGONS ORIGINATOR TÜV RHEINLAND INTERTRAFFIC GMBH SUBJECT RELATED TO CR TSI WAG DOC NO (2006/861/EC) DESCRIPTION AND BACKGROUND EXPLANATION Scope: This question is related to minimum brake performance requirements for freight wagons with disc brakes. Description: The Table under clause 4.2.4.1.2.2 Braking Performance elements which defines the The minimum braking performance for brake-modes G and P differentiates in Case A - Brake only on wheels (Brake blocks) and Case B Other cases so any brake that is not using brake blocks on wheels, i.e. disc brakes. The different requirements (case A and B) would cause a considerable difference in the brake performances within a train composition with a mixed service of block brake and disc brake freight cars. In particular in case of SS wagons that are equipped with disk brakes (λ=100%) and S wagons that are equipped with wheel brakes (λ=65%). Due to higher deviation in the brake performance the tension and stress at the intercar couplers could be significantly increased. The referred table is shown below: QUESTION & CLARIFICATION
Page 2 of 6 QUESTION & CLARIFICATION
Page 3 of 6 Question: Does a wagon that is equipped with disks brakes comply with the TSI if it meets only the required values of Case A? SUGGESTED RESOLUTION / INTERPRETATION 1) To improve the above described situation of the different brake performances in a mixed service the requirements for the brake performance should not depend on the type of brake (i.e. block brakes or disc brakes) Since the brake performance is typically determined by the block brake characteristic and the majority of wagons are fitted with this type of brake the common solution should be only the application of the brake performance of Case A also to wagon with disc brakes. The latest revision of the Wagon TSI, Final draft 1.0, 07.11.2011 shows this solution already. Please refer to the table below. 2) Case B may be kept as option for operators that operate train compositions with disc brake only. 3) The solution should be limited to wagons to be assessed according to TSI 2006/861/EC and amendments 2009/107/EC QUESTION & CLARIFICATION
Page 4 of 6 QUESTION & CLARIFICATION
Page 5 of 6 (6) The maximum mean retardation force admitted (for running speed at 100km/h) is 18x0,91 = 16,5 kn/axle. This value comes from the maximum braking energy input QUESTION permitted on a clasp braked & CLARIFICATION wheel with a nominal new diameter in the range of [920 mm; 1 000 mm] during braking (the brake weight shall be limited to 18 tonnes/axle). Usually a unit, with V max = 100 km/h and fitted with a variable relay is designed to obtain λ = 100% up to 14.5 t/axle. (7) The maximum mean retardation force admitted (for running speed at 120km/h) is 18x0,88 = 16 kn/axle. This value comes from the
Page 6 of 6 ORGANISATION(S) REQUESTED TO RESPOND (E.G. TSI GROUP, RISC, ERA ETC.) DATE OF AGREEMENT AT NB RAIL PLENARY MEETING RESPONSE FROM ORGANISATION ABOVE QUESTION & CLARIFICATION