ORIGINATOR SUBJECT ELATED TO · passenger coach buffers as defined in EN 15551:2009 with a stroke of 110 mm are generally used on coaches to protect them against buffing impacts at

QUESTION / CLARIFICATION Q&C RST-012 Issue 01 Date: 08/02/2012 Page 1 of 8

CO-ORDINATION BETWEEN NOTIFIED BODIES

DIRECTIVES 2008/57/EC AND SUBSEQUENT AMENDMENTS

ON THE INTEROPERABILITY OF THE RAILWAY SYSTEMS

WITHIN THE UNION

QUESTION & CLARIFICATION

TITLE

INTEROPERABILITY CONSTITUENT – "BUFFER" (ON COACHES ACCORDING TSI_HS_RST)

ORIGINATOR SUBJECT RELATED TO

SCONRAIL LTD. TSI_HS_RST (2008/232/EC)

DESCRIPTION AND BACKGROUND EXPLANATION

Scope

Interpretation of the requirement for conventional buffers on passenger coaches, certified in accordance with TSI_HS_RST (2008/232/EC).

Introduction

The technical specification for interoperability relating to the ‘rolling stock’ sub-system of the trans-European high-speed rail system TSI_HS_RST (2008/232/EC) has obviously been written for multiple units in fixed configuration. Passenger coaches were not in the focus of this TSI, even though they also are part of the high speed rolling stock.

The respective section in the TSI_HS_RST is phrased as follows:

4.2.2.2. End couplers and coupling arrangements to rescue trains

4.2.2.2.1. Subsystem requirements

(a) Class 1 trains ......

(b) Class 2 trains shall be equipped at each end either

— with an automatic centre buffer coupler as defined in clause 4.2.2.2.2.1

— or with buffing and draw gear components compliant with clause 4.2.2.2.2.2.

4.2.2.2.2.2. Buffing and draw gear components

The buffing and draw gear components shall be compliant with clause 4.2.2.1.2 of the Conventional Rail Rolling Stock Freight Wagons TSI 20051.

Technical Problem

Coaches to be certified in accordance with TSI_HS_RST, which are designed for a speed of 200 km/h and which are freely used in locomotive hauled trains (under the former RIC regime) are still designed and built. They are mixed with various interoperable coaches; there is no defined formation of the train. Therefore each coach could be “at each end of the train”.

1 This reference is not clear; there is no "Conventional Rolling Stock Freight Wagons TSI

2005". It is assumed, that the reference means: TSI_CR_WAG (2006/861/EC)





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Certain types of passenger coaches on the high speed rail system are equipped with crash buffers, fully compliant with the with the requirements of EN 15551:2009+A1 “Railway applications - Railway rolling stock – Buffers”, section 4.3 – Buffers with 110 mm stroke (for passenger coaches). These buffers however do not comply with some requirements for end couplers and coupling arrangements to rescue trains as defined in section 4.2.2.2. of the TSI_HS_RST; for this application a freight wagon buffer in accordance with the requirements of EN 15551:2009 would be required.

The deviation of a passenger coach (crash) buffer from a TSI_HS_RST compliant freight wagon buffer are:

a) The passenger coach (crash) buffers have lower dynamic (reversible) energy absorption capacity than freight wagon buffers, and will not meet this requirement because:

the dynamic energy absorption is the integral of force over the stroke; the force must build-up slower on a passenger coach buffer in order to limit the exposure of the passengers to longitudinal accelerations (the “load” on a passenger coach are people, not freight!)

without jeopardizing the requirement for the reduced longitudinal accelerations the stroke would have to be increased considerably (about double) in order to achieve the dynamic energy absorption capacity of > 30 kJ as required for a freight wagon buffer (the buffer would get too long and would not meet the geometric boundary conditions on the passenger coach end); further on the buffer then would exceed the buffer length requirement of EN 15551

passenger coach buffers as defined in EN 15551:2009 with a stroke of 110 mm are generally used on coaches to protect them against buffing impacts at speeds of up to 10 km/h.

b) The buffer head has a radius of 1’500 mm, as defined for passenger coach buffers in EN 15551 (a freight wagon buffer has a radius of 2’750 mm) and will not meet the TSI requirement.

This requirement for passenger coach buffers is based on safety criteria: Passenger coaches are longer than freight wagons and are featuring and longer overhang.

Therefore the transverse displacement and the angles between the two coach ends are much greater in S-curves than for freight wagons.

In order to guarantee that the two buffers are in contact with their surfaces and not the edge of the plate a smaller radius is mandatory for passenger coach buffers for safety reasons.

The passenger coach (crash) buffers are meeting all other requirements of the TSI as well as the additional requirements.

Special “passenger coach crash buffers in accordance with TSI_HS_RST” should not be designed, because:





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1. It would bee too stiff, exposing the passengers to excessive longitudinal accelerations

2. It would feature increased risks because of the non-adequate radius of the buffer plate

3. It would make the design of the coach more complex, because some of the crash functionality would have to be transferred to additional elements

4. A sub-optimal design would have to be conceived for the normal operational case of the train just to satisfy the formal requirement when rescuing a train

A passenger coach, equipped with a buffer fully compliant with the requirements for a passenger coach buffer as per EN 15551:2009, can be safely coupled to and operated with a rail vehicle, equipped with freight wagon buffers in accordance with the TSI and EN 15551:2009. It is not necessary for this part of the interoperability to be compliant with all the “internal” requirements of the freight wagon buffer in order to meet the essential interoperability functionality (which is really only required for the “emergency case when rescuing a train”)

Concept

A passenger coach can get a EC Type Examination Certificate in accordance with TSI_HS_RST (2008/232/CE) when it is equipped with buffers, meeting the requirements of TSI_CR_LOC+PAS (2011/291/EU), because the essential requirement for the interoperability are inevitably fulfilled.

Assessment of this buffer would be performed against the requirements, defined for passenger coach buffers in EN 15551:2009.

SUGGESTED RESOLUTION / INTERPRETATION

A passenger coach can get an EC Type Examination Certificate in accordance with TSI_HS_RST (2008/232/CE) when it is equipped with buffers, meeting the requirements of TSI_CR_LOC+PAS (2011/291/EU).

We propose that ERA issues a TO in the first step.

In the second step, this topic shall be covered in the merged passenger TSI for high and conventional speed rolling stock.

ERA 28/06/2012

RESPONSE FROM ORGANISATION ABOVE





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Documents

ORIGINATOR SUBJECT ELATED TO · passenger coach buffers as defined in EN 15551:2009 with a stroke of 110 mm are generally used on coaches to protect them against buffing impacts at