Railway applications - Vehicle end design for trams and light rail vehicles with respect to pedestrian safety

This technical report is applicable to tram vehicles according to EN 17343. Tram-Train vehicles, on track machines, infrastructure inspection vehicles and road-rail machines according to EN 17343 and demountable machines/machinery are not in the scope of this
technical report.
This technical report describes passive safety measures to reduce the consequences of collisions with pedestrians. These measures provide the last means of protection when all other possibilities of preventing an accident have failed, i.e.
- Design recommendations for the vehicle front to minimize the impact effect on a pedestrian when hit,
- Design recommendations for the vehicle front end for side (lateral) deflections in order to minimize the risk of being drawn under the vehicle on flat ground (embedded track),
- Design recommendations for the vehicle body underframe to not aggravate injuries to a pedestrian/body lying on the ground,
- Recommendations to prevent the pedestrian from being over-run by the leading wheels of the vehicle.
The following measures to actively improve safety are not in the scope of this technical report:
- Colour of front;
- Additional position lights;
- Additional cameras;
- Driver assistance systems;
- Additional acoustic warning devices, etc.;
- View of the driver / mirrors;
- Consequences for pedestrian injuries due to secondary impact with infrastructure (side posts, concrete ground, poles, trees, etc.).
The recommendations of this technical report only apply to new vehicles.

Bahnanwendungen - Fahrzeugkopfgestaltung von Straßenbahnen und Light rail Fahrzeugen im Hinblick auf den Passantenschutz

Applications ferroviaires - Conception de l'extrémité des tramways et véhicules ferroviaires légers pour la sécurité des piétons

Le présent Rapport technique s'applique aux tramways selon l'EN 17343 . Les trams-trains, les engins de travaux sur voie, les véhicules d'inspection de l'infrastructure et les machines rail-route selon l'EN 173431, ainsi que les machines déraillables ne sont pas couverts par le présent Rapport technique.
Le présent Rapport technique décrit les mesures de sécurité passive en vue de réduire les conséquences des collisions avec les piétons. Ces mesures décrivent les moyens de protection de dernier recours lorsque toutes les possibilités de prévention d'accidents ont échoué, par exemple :
- des recommandations de conception pour l'avant du véhicule afin d'atténuer l'impact d'une collision sur le piéton ;
- des recommandations de conception pour l'avant du véhicule, concernant la déviation latérale afin de réduire le risque de projection du piéton sous le véhicule sur terrain plat (voie encastrée) ;
- des recommandations de conception pour le châssis du véhicule afin de ne pas aggraver les blessures d'un piéton/corps allongé sur le sol ;
- des recommandations afin d'éviter un écrasement du piéton sous les roues avant du véhicule.
Le présent Rapport technique ne traite pas des mesures d'amélioration de la sécurité active suivantes :
- couleur de l'avant du véhicule ;
- feux de position supplémentaires ;
- caméras supplémentaires ;
- systèmes d'assistance à la conduite ;
- systèmes d'avertissement sonore supplémentaires, etc. ;
- visibilité du conducteur/rétroviseurs ;
- blessures liées à un impact secondaire avec l'infrastructure (poteaux latéraux, sol en béton, arbres, etc.).
Les recommandations du présent Rapport technique s'appliquent exclusivement aux véhicules neufs.

Železniške naprave - Zunanja konstrukcija tramvajskih in lahkih železniških vozil glede na varnost pešcev

Ta dokument se uporablja za tramvajska vozila v skladu s standardom prEN 17343. Tramvajska vozila, tirni stroji, vozila za pregledovanje infrastrukture in cestna železniška vozila v skladu s standardom prEN 17343 ter demontažni stroji/ustroji ne spadajo na področje uporabe tega tehničnega poročila.
Ta dokument opisuje pasivne varnostne ukrepe za zmanjšanje posledic trkov s pešci. Ti ukrepi zagotavljajo zadnje sredstvo za zaščito, kadar vse druge možnosti preprečevanja nesreče niso uspele, t.j.:
– oblikovalska priporočila za prednji del vozila, s katerimi se zmanjša vpliv na pešca ob trku;
– oblikovalska priporočila za prednji del vozila za bočne (lateralne) odklone, s katerimi se zmanjša tveganje, da bi pešca na ravnem terenu (vdelana proga) potegnilo pod vozilo;
– oblikovalska priporočila za podvozje karoserije vozila, s katerimi se prepreči dodatno poškodovanje pešca/telesa, ki leži na tleh;
– priporočila za oblikovanje, s katerimi se prepreči, da bi vodilna kolesa vozila povozila pešca.
Naslednji ukrepi za aktivno izboljšanje varnosti niso zajeti v tem dokumentu:
– barva prednjega dela vozila;
– dodatne pozicijske luči;
– dodatne kamere;
– sistemi za pomoč voznikom;
– dodatne zvočne opozorilne naprave itd.;
– pogled voznika/zrcal;
– posledice za poškodbe pešcev zaradi sekundarnega trka z infrastrukturo (stranski stebri, betonska tla, drogovi, drevesa itd.).
Priporočila tega dokumenta veljajo samo za nova vozila.

General Information

Status
Published
Publication Date
14-Jan-2020
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
15-Jan-2020
Completion Date
15-Jan-2020

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SLOVENSKI STANDARD
SIST-TP CEN/TR 17420:2020
01-marec-2020

Železniške naprave - Zunanja konstrukcija tramvajskih in lahkih železniških vozil

glede na varnost pešcev

Railway applications - Vehicle end design for trams and light rail vehicles with respect to

pedestrian safety
Bahnwendungen â Fahrzeugkopfgestaltung von StraÃen- und Stadtbahnen im Hinblick
auf den Passantenschutz

Applications ferroviaires - Conception de l'extrémité des véhicules pour tramways et

métros légers en ce qui concerne la sécurité des piétons
Ta slovenski standard je istoveten z: CEN/TR 17420:2020
ICS:
45.140 Oprema za podzemne vlake, Metro, tram and light rail
tramvaje in lahka tirna vozila equipment
SIST-TP CEN/TR 17420:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TP CEN/TR 17420:2020
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SIST-TP CEN/TR 17420:2020
CEN/TR 17420
TECHNICAL REPORT
RAPPORT TECHNIQUE
January 2020
TECHNISCHER BERICHT
ICS 45.060.10; 45.140
English Version
Railway applications - Vehicle end design for trams and
light rail vehicles with respect to pedestrian safety

Applications ferroviaires - Conception de l'extrémité Bahnanwendungen - Fahrzeugkopfgestaltung von

des véhicules pour tramways et véhicule ferroviaire Straßenbahnen und Light rail Fahrzeugen im Hinblick

léger en ce qui concerne la sécurité des piétons auf den Passantenschutz

This Technical Report was approved by CEN on 23 September 2019. It has been drawn up by the Technical Committee CEN/TC

256.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,

Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 17420:2020 E

worldwide for CEN national Members.
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Contents Page

European foreword ....................................................................................................................................................... 3

1 Scope .................................................................................................................................................................... 3

2 Normative references .................................................................................................................................... 4

3 Terms and definitions ................................................................................................................................... 5

4 Symbols and abbreviations ......................................................................................................................... 7

5 Front end design of tram vehicles and light rail vehicles ................................................................. 7

6 Reference collision scenario type A.......................................................................................................... 8

7 Reference collision scenario type B....................................................................................................... 18

Annex A (informative) PACM test protocol report ........................................................................................ 24

Bibliography ................................................................................................................................................................. 30

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European foreword

This document (CEN/TR 17420:2020) has been prepared by Technical Committee CEN/TC 256 “Railway

applications”, the secretariat of which is held by DIN.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

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1 Scope

This technical report is applicable to tram vehicles according to EN 17343 . Tram-Train vehicles, on track

machines, infrastructure inspection vehicles and road-rail machines according to EN 17343 and

demountable machines/machinery are not in the scope of this technical report.

This technical report describes passive safety measures to reduce the consequences of collisions with

pedestrians. These measures provide the last means of protection when all other possibilities of

preventing an accident have failed, i.e.:

— design recommendations for the vehicle front to minimize the impact effect on a pedestrian when

hit,

— design recommendations for the vehicle front end for side (lateral) deflections in order to minimize

the risk of being drawn under the vehicle on flat ground (embedded track),

— design recommendations for the vehicle body underframe to not aggravate injuries to a

pedestrian/body lying on the ground,

— recommendations to prevent the pedestrian from being over-run by the leading wheels of the

vehicle.

The following measures to actively improve safety are not in the scope of this technical report:

— colour of front;
— additional position lights;
— additional cameras;
— driver assistance systems;
— additional acoustic warning devices, etc.;
— view of the driver / mirrors;

— consequences for pedestrian injuries due to secondary impact with infrastructure (side posts,

concrete ground, poles, trees, etc.).
The recommendations of this technical report only apply to new vehicles.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

EN 15663:2017+A1:2018, Railway applications – Vehicle reference masses
Under preparation. Stage at the time of publication: prEN 17343.
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3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at http://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
tram vehicle
urban rail vehicle designed to run on a tram network
[SOURCE: EN 17343:— , 3.1.6.1.2.3]
3.2
collision scenario

collision scenario derived from accident analysis that is applicable for design and assessment

3.3
head injury criterion
HIC
measure of the likelihood of head injury stemming from impact or acceleration

Note 1 to entry: The head injury criterion (HIC) should not exceed a value of 1 000 over any time interval of up

to 15 ms. The HIC is calculated using the following formula:
25,
A dt
HIC t− t
( )
2 1
tt−
( )
2 1
where
t1 represents the start of the time interval,
t represents the end of the time interval,
HIC is the maximum value of HIC for (t – t ) ≤ 15 ms,
2 1
A is the resultant acceleration
2 22
A A++A A
R XY Z
where
A , A and A represent the accelerations in g in X, Y and Z directions.
X Y Z

Note 2 to entry: The 15 ms time frame relates to the original biomechanical testing used to establish the HIC as

an injury criterion commonly accepted for impacts against fixed surfaces.

Note 3 to entry: This criterion can be used to assess the safety regarding vehicles, personal protective gear and

sports equipment.
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3.4
light rail vehicle

urban rail vehicle designed to be line of sight operated and/or to be operated on segregated lines by

signalization
Note 1 to entry: German: Light-Rail-Fahrzeug.

Note 2 to entry: Light rail vehicle is a generic term used to distinguish a vehicle from heavy rail vehicles.

[SOURCE: EN 17343:—, 3.1.6.1.2.1, modified — The end of the original definition "signal-controlled

segregated lines" was replaced with "segregated lines by signalization" and Note 1 to entry" was added.]

3.5
tram system

urban rail system operated on infrastructure shared with road traffic and/or its own infrastructure

[SOURCE: EN 17343:—, 3.1.2.2, modified — The original Notes to the definition were not reproduced

here.]
3.6
rescue mannequin

life size model of a person used in tests to simulate what happens to people when a vehicle gets into an

accident (with a pedestrian)
3.7
anthropomorphic test device
ATD
model or mannequin of a person used in tests
3.8
pedestrian
walking, standing or lying person
Note 1 to entry: In this context, person can refer to an adult or a child.

Note 2 to entry: Any recommendations defined in this document for walking or standing persons will also

improve the impact effect on cyclists (self-propelled or on e-bikes), skaters, persons in wheel chairs, or children in

baby buggies, etc. Persons on e-scooters, motorbikes, etc. are not considered.
3.9
pedestrian deflector

technical device that pushes the pedestrian out of the path of the tramway in case of a collision

3.10
pedestrian anti-crush mechanism
PACM
mechanism like a trap basket / drop down tray
3.11
front cover
front fairings

outside front panels of the tram vehicle structure below the windscreen, i.e. streamlining

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3.12
tram-train vehicle

vehicle designed to operate on urban and/or regional networks, in track-sharing operation and

interfacing with road traffic

[SOURCE: EN 17343:—, 3.1.6.1.3, modified — The current definition was substantially reworded.]

3.13
tram width

overall width of the car body excluding additionally fixed equipment like mirrors and cameras

4 Symbols and abbreviations
ATD Anthropomorphic Test Device
IIV Infrastructure Inspection Vehicle
LRV Light Rail Vehicle
OTM On-Track Machine

PACM Pedestrian Anti-Crush Mechanism (fr: dispositif anti-écrasement d'un piéton (DAEP))

5 Front end design of tram vehicles and light rail vehicles
5.1 Objective / concept

The objectives of this technical report are to provide protection for pedestrians by reducing the risk of

severe injuries, of being trapped under the vehicle, of being hit by underfloor equipment, and of being

run over by the wheels of the vehicle. All tram vehicles and light rail vehicles should have a design that

enables a pedestrian’s body to be deflected rather than be run over during an impact. The pedestrian is

considered to have been deflected onto the side once the pedestrian has been moved out of the path of

the vehicle.
5.2 Sequence of an impact

The entire sequence of an impact can be divided into three phases. All three phases can cause severe

injuries to the involved pedestrian:

— Phase 1 is considered as primary impact. A pedestrian, standing or walking in front of a moving tram,

comes in contact with the vehicles front end. It is assumed that the pedestrian is moving

perpendicular to the direction of the tram. Consequently, the tram hits the pedestrian at his side.

— Phase 2 is considered as secondary impact. Once being hit by the tram the pedestrian is thrown

forward or to the side. As a consequence, the pedestrian impacts on the infrastructure (e.g. pavement,

track, side poles).

— Phase 3 is considered as tertiary impact. As a consequence of Phase 2 the pedestrian might lay on the

track, be overrun by the tram and collide again with the lower parts of the tram.

This technical report focuses on the consequences of the primary and tertiary impact. The consequences

of a secondary impact are out of the scope of this technical report. Due to the recommendations given in

this technical report, the consequences for the pedestrian in the primary impact and the risk to be run

over by the wheels of the vehicle should be minimized (see 7.3).
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5.3 Reference collision scenarios

The following reference collision scenarios with pedestrians should be considered:

— Type A: Collision with a passing pedestrian in the front area of the vehicle;

— Type B: Collision with a lying pedestrian on the ground in front of the vehicle.

Collision type A covers the effects of a primary impact and influences the effects of the downstream

phases.
The tertiary impact is regarded to be identical to the collision type B.
6 Reference collision scenario type A
6.1 Introduction

The general approach is to achieve compliance with the geometrical requirements defined in 6.3.

If it is not possible to comply with all geometric parameters, numerical simulations can be carried out to

demonstrate the ability to limit the risk of severe injuries and to encourage lateral ejection. Nevertheless,

the criteria for h in the impact surface and for the avoidance of sharp edges in the extended impact zone

should still be fulfilled in this case (from 6.3).

The recommendations of this section focus on the side impact against a pedestrian at the front end (i.e.

passing pedestrian). Two categories of pedestrians are identified:
— a 6-year-old child, 1,10 m in height;
— a medium-sized adult, 1,75 m in height (50 percentile/average size).

If the requirements are fulfilled for these two categories, the design characteristics of the front end will

also be beneficial to the impact effect in collisions with other sizes of pedestrians.

6.2 Impact surfaces
6.2.1 General

The impact surface is part of the front face of a tram predestined for contact with pedestrians in case of a

collision and with the most likely possibility of severe injuries. This region should be used for evaluation

of the geometric requirements. The impact surface is divided into two zones:
— centre zone;
— intermediate zone.

The impact surface is defined as the front surface of the tram up to a height of 1,75 m from the ground

(the average height of an adult). The width of the impact surface is 50 % of the maximum tram width

centred to the tram centre line (see Figure 1),
The projection surface from the front view is used to define the impact surface.

Based on the current requirements for visibility the impact surface is not assumed to interfere with the

A-pillars of the tram front. If the impact surface overlaps the A-pillars nevertheless, then the impact

surface may be reduced to the width between the A-pillars at a height of 1,75 m from the ground, minus

100 mm on each side.
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6.2.2 Extended impact surface

The extended impact surface is defined in analogy to the impact surface with the exception that the width

is 75 % of the maximum tram width.
The impact surface is displayed in Figure 1:
Figure 1 — Impact surface
6.3 Geometric criteria to reduce the severity of injuries
6.3.1 General

If the compliance with the geometric recommendations given in this chapter is proven, the HIC value is

assumed to stay below 1 000. In this case, any additional numerical analyses (according to 6.4) for this

proof are not mandatory but monitoring of this value is recommended.
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6.3.2 Objective of the desired kinematics

In order to limit severe injuries, in particular to the head, the body kinematic to be favoured is either to

block the shoulder and the torso as quickly as possible while limiting the rotation of the torso or to

progressively impact-the pedestrian starting from the lower legs up to the torso and shoulders.

All trams and light rail vehicles should have a design that enables a body to be deflected rather than be

run over in an accident. The objective is to limit the risk of intrusion of a pedestrian, including a child,

under the tram.
6.3.3 Definition of evaluation points

The criteria mentioned are defined to ensure a lateral deflection of a body in case of collision with a

pedestrian. Additionally, the risk of fatal head injury at all points of the potential impact surface is reduced

(criterion: HIC ≤ 1 000). Figure 2 shows the entire width of the tram and the angle α of tangents at the

front in height of the foremost points below z = 1,75 m to ensure an efficient deflection to the side.

The values of the geometric parameters at the specific points should be measured to ensure compliance

with the criteria. In case of a symmetrical tram, regarding the XZ plane, the values may be measured for

one half only.
Figure 2 — Definition of evaluation points
6.3.4 Geometric parameter definition
The parameters β and d should be applied at all points on the impact surface.
The following geometric parameters are taken into account:
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Figure 3 — Side view of vehicle front (projection to cutting plane parallel to XZ plane)

The parameters in Figure 1 to Figure 3 are defined in the following table:
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Table 1 — Definitions of geometric parameters for Figure 1 to Figure 3
Parameter Definition

h h is determined by cutting the impact surface with planes parallel to the XZ plane.

s s

h corresponds to the height of the foremost points of these intersection curves (e.g. the

Z coordinate of the maximum X abscissa point).

h is determined for the vehicle in design mass in running working order according to

EN 15663:2017+A1:2018, Table 5 (based on EN 15663).

α The h points and also the foremost points below z = 1,75 m within the complete width

of the tram are combined with a curve and projected to the XY plane, α is the angle

between the y-axis and the tangent to the projected curve.

Line B Line B is defined by the point h and the upper point of the impact surface of the

corresponding cutting plane (parallel to XZ plane) at a height of 1,75 m (see Figure 3).

β The angle β defines the inclination of line B versus the Z axis (β ≥ 10°)

d d defines the tolerance band centred by line B and marked by two lines parallel to line

f f

B with a distance of d /2. Any front geometries in the impact surface should lie within

this tolerance band (d = 250 mm), measured horizontally. d should be minimized.
f f
g ground clearance - refer to 7.2

NOTE 1 An intersection curve with a vertical slope at the maximum abscissa point gives several values of

h (see 6.3.5.2).
NOTE 2 Different values of Y can give different values for h (see 6.3.5.2).
6.3.5 Evaluation criteria for impact surface
6.3.5.1 Criterion for angle α

The angle α should be continuously increased by growing lateral coordinate (y-axis).

The criterion for angle α depends on the lateral position of the evaluation point (see Figure 2: ignoring

transitions and blending):

— Centre zone of impact surface: Surface at the centre of the front end (15 % range of the tram width

in the centre - see Figure 2) should be curved (in order to take into account any design constraints).

This width represents the side-on envelope of a regular-sized human. From the transition point to

the intermediate zone, the angle α should be equal to or more than 15°.

— Intermediate zone of impact surface (lateral position between centre zone (15 % range of the tram

width) and a lateral position of the ± 50 % value of half of the tram width measured from the centre

line): The angle α should be continuously increased to reach equal or more than 30° from the

transition point to the extended impact zone.

— Extended impact surface (lateral position between 50 % and 75 %): The angle α should be

continuously increased (ignoring transitions and blending) from 30° to reach equal or more than 60°.

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6.3.5.2 Criterion for h

In the impact surface the curve of the most protruding points of the impact area (curve of the h points)

should have the lowest Z coordinates possible in order to hit an adult pedestrian below the knees:

h ≤ 350 mm (see also 6.3.4).

If there are several values for h , the lowest h value should be considered/assumed.

s s
6.3.5.3 Criterion for angle β
The angle β should be ≥ 10° over the whole width of the impact surface.
6.3.6 Guiding procedure
The evaluation should be performed according to the following steps:
1) Define the impact surface;

2) Project the front surface to the ground plane (XY) to determine the foremost boundary line for h

and α determination;

3) Determine the evaluation points, e.g. different Y-values for the cutting planes – the evaluation points

should cover the extremities of the impact surface;

4) Determine the values for the angle α in the evaluation points and check the criteria for angle α;

5) Sketch line B in the different cutting planes;
6) Determine d and check the criteria;
7) Determine β and check the criteria.

If these criteria are not met, numerical analyses with ATD models should be carried out to prove

compliance with the criteria or the front design has to be adapted.
6.3.7 Front end geometry
6.3.7.1 Sharp edges and protruding parts

All exposed rigid edges on the extended impact surface (75 % of tram width) and up to a height of

1 750 mm should have radius of at least 10 mm. An edge is considered as exposed only if it can be

contacted by a sphere of 100 mm diameter. In case of pillars that widen towards the top, the requirement

for the absence of sharp ends is valid for the entire range of the impact and extended impact surface

(including the A-pillars).

Any gaps between skirts should be as small as possible. The surface of the A-pillar and/or its cover layer

should be as soft as possible.

Sharp edges should be avoided or covered, e.g. windscreen wiper motor output shaft. Windscreen wiper

arms and blades are excluded. They are considered to be flexible. A rigid edge should be considered to be

one using material with a Shore A hardness greater than 50. For exposed rigid external edges, where the

edge projects not more than 3,2 mm from the adjacent surfaces, the requirements for minimum radii

should not apply, provided that the height of the projection is not more than half its width and its edges

are blunted.
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For the transition between two parts forming a continuous surface (typically transition between two

parts of fairing), the minimum radius of the edges does not apply provided that the gap between the two

adjacent surfaces is less than 20 mm. Edges should be blunted.
Key
R radius 100 mm of sphere
Figure 4 — Transition condition between two parts forming a continuous surface

Coupling elements on trams and light rail vehicles should be covered and the rigidity of their structure

should not represent a risk of aggravating injuries in relation to other nearby structures.

Any rear-view cameras or rear-view mirrors should be positioned higher than 1,75 m.

6.3.7.2 Front window / windscreen

The windscreen at the front window should comply with the requirements of ECE R43 or of EN 15152.

In general, a lower windscreen stiffness is considered favourable, as the risk for severe injuries is

reduced.
6.3.7.3 Tram-surfing
Tram-surfing on the lateral and front surfaces should be impeded.
6.3.8 Summary of recommendations to minimize the severity of pedestrian injuries

This chapter summarizes the recommendations that should minimize the severity of pedestrian injuries.

The following limits for the geometric parameters are recommended:
— β ≥ 10°;
— d ≤ 250 mm.

These parameters should be checked in the cutting planes parallel to the XZ plane in the evaluation points

of the impact surface (see Figures 2 and 3).
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Table 2 — Summary of recommendations
Zone considered Recommendation Objective
Front surface of the vehicle no possibility of tram-surfing Avoid tram-surfing
on protruding or external built-
in parts
Extended impact surface 30° ≤ α < 60° Deflection to the side
Covering lights, windscreen Limit aggressiveness of local
wiper motor output shaft, shapes by shielding the main
automatic coupling components
Shape of the front end with Limit aggressiveness of local
radius ≥ 10 mm shapes by rounding the curves
over 10 mm radius
Intermediate zone of impact 15° ≤ α < 30° Deflection to the side
surface
Impact surface h ≤ 350 mm Avoid to push down the
pedestrian
Inclination of impact surface Avoid severe injuries and avoid
(Line B): β ≥ 10° to push down the pedestrian
Surface of the front end inside a Avoid severe injuries and avoid
tolerance band of width to push down the pedestrian
d ≤ 250 mm and centred on
line B
The windscreen at the front Avoid severe head injuries
window should comply with
the requirements of ECE R43 or
of EN 15152.
6.4 Numerical simulation of pedestrian impact scenario type A
6.4.1 Introduction

As an alternative to the geometrical recommendations of 6.3, numerical simulations of pedestrian impact

scenarios may be conducted to demonstrate the ability of the front-end design to limit the risk of severe

injuries and to encourage lateral ejection.

If numerical simulations are applied, the criteria for h in the impact surface and for the avoidance of

sharp edges in the extended impact surface should still be fulfilled (see 6.3).

The numerical models applied should be validated by the comparison with dynamic test results. A

maximum deviation of 20 % between test and numerical results is the criterion for the validation. Force-

deflection curves and force-time curves have to be evaluated. A special focus should be put on the

modelling of the front windscreen.

In this case, the front end of the vehicle should be assessed for the following reference impact scenario.

The front end of the vehicle should be assessed for two positions of the pedestrian relative to the vehicle,

and be aligned (see Figure 5 and Figure 6):
— at the 15 % value of half of the tram width;
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— at the 50 % value of half of the tram width.

The vehicle is initially moving at 20 km/h. The pedestrian is assumed to be a 50th percentile male,

standing still (initially), facing the vehicle sideways/body turned sideways to the vehicle, one step

forward/in the middle of a stride.
Figure 5 — Example for 15 % position
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Figure 6 — Example for 50 % position

The vehicle is moving on a horizontal track and does not decelerate, even during and after the impact

with the pedestrian. The pedestrian stands atop the rail level or at the running surface for rubber-tired

wheels.

Due to the significant mass difference between a rail vehicle and a pedestrian, the vehicle is considered

to have a constant velocity of 20 km/h).

For non-symmetric vehicle front ends, the assessment should be performed for both halves/sides of the

vehicle.

It should be verified that the numerical model of the pedestrian used for the impact simulations is

validated from directly comparable impact configurations. Typically, the use of a numerical model of a

seated person positioned in a standing position is prohibited.

The numerical model of the front-end surface of the vehicle should at least comprise all parts potentially

impacted by the pedestrian in the impact scenarios. The scope of parts represented in the model may be

extended to avoid unrealistic effects close to the boundary conditions. The components situated behind

fairings (structural elements in general) should also be represented to reflect potential hard contact

points.
In general, the parts to be modelled should be:
— front fairings,
— windscreen,
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— cabin supporting structure,
— external fittings,
— lights,
— wiper motor shaft,
— coupler (if not covered by fairings).
6.4.2 Modelling hypotheses for a pedestrian – tram / LRV collision
The ATD to be used should meet the following criteria:
— Validated computer models of the anthropomorphic test devices (ATDs) are used.

— Adult dummies that represent the 50 percentile male and a 6-year-old child. With the child ATD, it

should be possible to verify whether the results obtained with the adult ATD do not result in fatal

injuries for the child.
— The tram should be modelled so that it
...

SLOVENSKI STANDARD
kSIST-TP FprCEN/TR 17420:2019
01-september-2019

Železniške naprave - Zunanja konstrukcija tramvajskih in lahkih železniških vozil

glede varnosti pešcev

Railway applications - Vehicle end design for trams and light rail vehicles with respect to

pedestrian safety
Bahnwendungen â Fahrzeugkopfgestaltung von StraÃen- und Stadtbahnen im Hinblick
auf den Passantenschutz

Applications ferroviaires - Conception de l'extrémité des véhicules pour tramways et

métros légers en ce qui concerne la sécurité des piétons
Ta slovenski standard je istoveten z: FprCEN/TR 17420
ICS:
45.140 Oprema za podzemne vlake, Metro, tram and light rail
tramvaje in lahka tirna vozila equipment
kSIST-TP FprCEN/TR 17420:2019 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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kSIST-TP FprCEN/TR 17420:2019
FINAL DRAFT
TECHNICAL REPORT
FprCEN/TR 17420
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
May 2019
ICS 45.060.10; 45.140
English Version
Railway applications - Vehicle end design for trams and
light rail vehicles with respect to pedestrian safety

Applications ferroviaires - Conception de l'extrémité Bahnwendungen â¿¿ Fahrzeugkopfgestaltung von

des véhicules pour tramways et métros légers en ce qui Straÿen- und Stadtbahnen im Hinblick auf den

concerne la sécurité des piétons Passantenschutz

This draft Technical Report is submitted to CEN members for Vote. It has been drawn up by the Technical Committee CEN/TC

256.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are

aware and to provide supporting documentation.

Warning : This document is not a Technical Report. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a Technical Report.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. FprCEN/TR 17420:2019 E

worldwide for CEN national Members.
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Contents Page

European foreword ....................................................................................................................................................... 3

1 Scope .................................................................................................................................................................... 4

2 Normative references .................................................................................................................................... 4

3 Terms and definitions ................................................................................................................................... 4

4 Symbols and abbreviations ......................................................................................................................... 7

5 Front end design of tram vehicles and light rail vehicles ................................................................. 7

5.1 Objective / concept ......................................................................................................................................... 7

5.2 Sequence of an impact ................................................................................................................................... 7

5.3 Reference collision scenarios ..................................................................................................................... 7

6 Reference collision scenario type A.......................................................................................................... 8

6.1 Introduction ...................................................................................................................................................... 8

6.2 Impact surfaces ................................................................................................................................................ 8

6.2.1 General ................................................................................................................................................................ 8

6.2.2 Extended impact surface .............................................................................................................................. 8

6.3 Geometric criteria to reduce the severity of injuries ......................................................................... 9

6.3.1 General ................................................................................................................................................................ 9

6.3.2 Objective of the desired kinematics ......................................................................................................... 9

6.3.3 Definition of evaluation points ............................................................................................................... 10

6.3.4 Geometric parameter definition ............................................................................................................. 10

6.3.5 Evaluation criteria for impact surface .................................................................................................. 12

6.3.6 Guiding procedure ....................................................................................................................................... 13

6.3.7 Front end geometry ..................................................................................................................................... 13

6.3.8 Summary of recommendations to minimize the severity of pedestrian injuries ................. 14

6.4 Numerical simulation of pedestrian impact scenario type A ....................................................... 15

6.4.1 Introduction ................................................................................................................................................... 15

6.4.2 Modelling hypotheses for a pedestrian – tram / LRV collision .................................................... 18

6.4.3 Criteria ............................................................................................................................................................. 18

7 Reference collision scenario type B....................................................................................................... 18

7.1 Introduction ................................................................................................................................................... 18

7.2 Objectives ........................................................................................................................................................ 18

7.3 Assessment of a PACM ................................................................................................................................ 19

7.4 Validation program for PACM .................................................................................................................. 19

7.4.1 Test objectives ............................................................................................................................................... 19

7.4.2 Test conditions .............................................................................................................................................. 19

7.4.3 Run over tests ................................................................................................................................................ 20

7.4.4 Documents to be provided ........................................................................................................................ 22

Annex A (informative) PACM test protocol report .......................................................................................... 24

Bibliography ................................................................................................................................................................. 28

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European foreword

This document (FprCEN/TR 17420:2019) has been prepared by Technical Committee CEN/TC 256

“Railway applications”, the secretariat of which is held by DIN.
This document is currently submitted to the Vote on TR.
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1 Scope

This document is applicable to tram vehicles according to prEN 17343. Tram-Train vehicles, on track

machines, infrastructure inspection vehicles and road-rail machines according to prEN 17343 and

demountable machines/machinery are not in the Scope of this Technical Report.

This document describes passive safety measures to reduce the consequences of collisions with

pedestrians. These measures provide the last means of protection when all other possibilities of

preventing an accident have failed, i.e.:

— design recommendations for the vehicle front to minimize the impact effect on a pedestrian when

hit,

— design recommendations for the vehicle front end for side (lateral) deflections in order to minimize

the risk of being drawn under the vehicle on flat ground (embedded track),

— design recommendations for the vehicle body underframe to not aggravate injuries to a

pedestrian/body lying on the ground,

— recommendations to prevent the pedestrian from being over-run by the leading wheels of the

vehicle.

The following measures to actively improve safety are not in the Scope of this document:

— colour of front;
— additional position lights;
— additional cameras;
— driver assistance systems;
— additional acoustic warning devices, etc.;
— view of the driver / mirrors;

— consequences for pedestrian injuries due to secondary impact with infrastructure (side posts,

concrete ground, poles, trees, etc.).
The recommendations of this document only apply to new vehicles.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

EN 15663:2017+A1:2018, Railway applications – Vehicle reference masses
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at http://www.iso.org/obp
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— IEC Electropedia: available at http://www.electropedia.org/
3.1
tram vehicle
urban rail vehicle designed to run on a tram network
[SOURCE: prEN 17343:2019, 3.1.6.1.2.3]
3.2
collision scenario

collision scenario derived from accident analysis that is applicable for design and assessment

3.3
head injury criterion
HIC
measure of the likelihood of head injury stemming from impact or acceleration

Note 1 to entry: The head injury criterion (HIC) should not exceed a value of 1 000 over any time interval of up

to 15 ms. The HIC is calculated using the following formula:
25,
A dt
HIC t− t
( )
2 1
tt−
( )
2 1
where
t represents the start of the time interval,
t represents the end of the time interval,
HIC is the maximum value of HIC for (t – t ) ≤ 15 ms,
2 1
A is the resultant acceleration
2 22
A A++A A
R XY Z
where
A , A and A represent the accelerations in g in X, Y and Z directions.
X Y Z

Note 2 to entry: The 15 ms time frame relates to the original biomechanical testing used to establish the HIC as

an injury criterion commonly accepted for impacts against fixed surfaces.

Note 3 to entry: This criterion can be used to assess the safety regarding vehicles, personal protective gear and

sports equipment.
3.4
light rail vehicle

urban rail vehicle designed to be line of sight operated and/or to be operated on segregated lines by

signalization
Note 1 to entry: German: Light Rail-Fahrzeug.

Note 2 to entry: Light rail vehicle is a generic term used to distinguish a vehicle from heavy rail vehicles.

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[SOURCE: prEN 17343:2019, 3.1.6.1.2.1, modified — The end of the original definition "signal-controlled

segregated lines" was replaced with "segregated lines by signalization" and Note 1 to entry" was added.]

3.5
tram system

urban rail system operated on infrastructure shared with road traffic and/or its own infrastructure

[SOURCE: prEN 17343:2019, 3.1.2.2, modified — The original Notes to the definition were not

reproduced here.]
3.6
rescue mannequin

life size model of a person used in tests to simulate what happens to people when a vehicle gets into an

accident (with a pedestrian)
3.7
anthropomorphic test device
ATD
model or mannequin of a person used in tests
3.8
pedestrian
walking, standing or lying person
Note 1 to entry: In this context, person can refer to an adult or a child.

Note 2 to entry: Any recommendations defined in this document for walking or standing persons will also

improve the impact effect on cyclists (self-propelled or on e-bikes), skaters, persons in wheel chairs, or children in

baby buggies, etc. Persons on e-scooters, motorbikes, etc. are not considered.
3.9
pedestrian deflector

technical device that pushes the pedestrian out of the path of the tramway in case of a collision

3.10
pedestrian anti-crush mechanism
PACM
mechanism like a trap basket / drop down tray
3.11
front cover
front fairings

outside front panels of the tram vehicle structure below the windscreen, i.e. streamlining

3.12
tram-train vehicle

vehicle designed to operate on urban and/or regional networks, in track-sharing operation and

interfacing with road traffic

[SOURCE: prEN 17343:2019, 3.1.6.1.3, modified — The current definition was substantially reworded.]

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3.13
tram width

overall width of the car body excluding additionally fixed equipment like mirrors and cameras

4 Symbols and abbreviations
ATD Anthropomorphic Test Device
IIV Infrastructure Inspection Vehicle
LRV Light Rail Vehicle
OTM On-Track Machine

PACM Pedestrian Anti-Crush Mechanism (fr: dispositif anti-écrasement d'un piéton)

5 Front end design of tram vehicles and light rail vehicles
5.1 Objective / concept

The objectives of this technical report are to provide protection for pedestrians by reducing the risk of

severe injuries, of being trapped under the vehicle, of being hit by underfloor equipment, and of being

run over by the wheels of the vehicle. All tram vehicles and light rail vehicle should have a design that

enables a pedestrian’s body to be deflected rather than be run over during an impact. The pedestrian is

considered to have been deflected onto the side once the pedestrian has been moved out of the path of

the vehicle.
5.2 Sequence of an impact

The entire sequence of an impact can be divided into three phases. All three phases can cause severe

injuries to the involved pedestrian:

— Phase 1 is considered as primary impact. A pedestrian, standing or walking in front of a moving tram,

comes in contact with the vehicles front end. It is assumed that the pedestrian is moving

perpendicular to the direction of the tram. Consequently, the tram hits the pedestrian at his side.

— Phase 2 is considered as secondary impact. Once being hit by the tram the pedestrian is thrown

forward or to the side. As a consequence, the pedestrian impacts on the infrastructure (e.g. pavement,

track, side poles).

— Phase 3 is considered as tertiary impact. As a consequence of Phase 2 the pedestrian might lay on the

track, be overrun by the tram and collide again with the lower parts of the tram.

This technical report focuses on the consequences of the primary and tertiary impact. The consequences

of a secondary impact are out of the scope of this technical report. Due to the recommendations given in

this technical report, the consequences for the pedestrian in the primary impact and the risk to be run

over by the wheels of the vehicle should be minimized (see 7.3).
5.3 Reference collision scenarios

The following reference collision scenarios with pedestrians should be considered:

— Type A: Collision with a passing pedestrian in the front area of the vehicle;

— Type B: Collision with a lying pedestrian on the ground in front of the vehicle.

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Collision type A covers the effects of a primary impact and influences the effects of the downstream

phases.
The tertiary impact is regarded to be identical to the collision type B.
6 Reference collision scenario type A
6.1 Introduction

The general approach is to achieve compliance with the geometrical requirements defined in 6.3.

If it is not possible to comply with all geometric parameters, numerical simulations can be carried out to

demonstrate the ability to limit the risk of severe injuries and to encourage lateral ejection. Nevertheless,

the criteria for h in the impact surface and for the avoidance of sharp edges in the extended impact zone

should still be fulfilled in this case (from 6.3).

The recommendations of this section focus on the side impact against a pedestrian at the front end (i.e.

passing pedestrian). Two categories of pedestrians are identified:
— a 6-year-old child, 1,10 m in height;
— a medium-sized adult, 1,75 m in height (50 percentile/average size).

If the requirements are fulfilled for these two categories, the design characteristics of the front end will

also be beneficial to the impact effect in collisions with other sizes of pedestrians.

6.2 Impact surfaces
6.2.1 General

The impact surface is part of the front face of a tram predestined for contact with pedestrians in case of a

collision and with the most likely possibility of severe injuries. This region should be used for evaluation

of the geometric requirements. The impact surface is divided into two zones:
— centre zone;
— intermediate zone.

The impact surface is defined as the front surface of the tram up to a height of 1,75 m from the ground

(the average height of an adult). The width of the impact surface is 50 % of the maximum tram width

centred to the tram centre line (see Figure 1),
The projection surface from the front view is used to define the impact surface.

Based on the current requirements for visibility the impact surface is not assumed to interfere with the

A-pillars of the tram front. If the impact surface overlaps the A-pillars nevertheless, then the impact

surface may be reduced to the width between the A-pillars at a height of 1,75 m from the ground, minus

100 mm on each side.
6.2.2 Extended impact surface

The extended impact surface is defined in analogy to the impact surface with the exception that the width

is 75 % of the maximum tram width.
The impact surface is displayed in Figure 1:
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Figure 1 — Impact surface
6.3 Geometric criteria to reduce the severity of injuries
6.3.1 General

If the compliance with the geometric recommendations given in this chapter is proven, the HIC value is

assumed to stay below 1 000. In this case, any additional numerical analyses (according to 6.4) for this

proof are not mandatory but monitoring of this value is recommended.
6.3.2 Objective of the desired kinematics

In order to limit severe injuries, in particular to the head, the body kinematic to be favoured is either to

block the shoulder and the torso as quickly as possible while limiting the rotation of the torso or to

progressively impact-the pedestrian starting from the lower legs up to the torso and shoulders.

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All trams and light rail vehicles should have a design that enables a body to be deflected rather than be

run over in an accident. The objective is to limit the intrusion of a pedestrian, including a child, under the

tram.
6.3.3 Definition of evaluation points

The criteria mentioned are defined to ensure a lateral deflection of a body in case of collision with a

pedestrian. Additionally, the risk of fatal head injury at all points of the potential impact surface is reduced

(criterion: HIC ≤ 1 000). Figure 2 shows the entire width of the tram and the angle α of tangents at the

front in height of the foremost points below z = 1,75 m to ensure an efficient deflection to the side.

The values of the geometric parameters at the specific points should be measured to ensure compliance

with the criteria. In case of a symmetrical tram, regarding the XZ plane, the values may be measured for

one half only.
Figure 2 — Definition of evaluation points
6.3.4 Geometric parameter definition
The parameters β and d should be applied at all points on the impact surface.
The following geometric parameters are taken into account:
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Figure 3 — Side view of vehicle front (projection to cutting plane parallel to XZ plane)

The parameters in Figure 1 to Figure 3 are defined in the following table:
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Table 1 — Definitions of geometric parameters for Figure 1 to Figure 3
Parameter Definition

h h is determined by cutting the impact surface with planes parallel to the XZ plane.

s s

h corresponds to the height of the foremost points of these intersection curves (e.g. the

Z coordinate of the maximum X abscissa point).

h is determined for the vehicle in design mass in running working order according to

EN 15663:2017+A1:2018, Table 5 (based on EN 15663).

α The h points and also the foremost points below z = 1,75 m within the complete width

of the tram are combined with a curve and projected to the XY plane, α is the angle

between the y-axis and the tangent to the projected curve.

Line B Line B is defined by the point h and the upper point of the impact surface of the

corresponding cutting plane (parallel to XZ plane) at a height of 1,75 m (see Figure 3).

β The angle β defines the inclination of line B versus the Z axis (β ≥ 10°)

d d defines the tolerance band centred by line B and marked by two lines parallel to line

f f

B with a distance of d /2. Any front geometries in the impact surface should lie within

this tolerance band (d = 250 mm), measured horizontally. d should be minimized.
f f
g ground clearance - refer to 7.2

NOTE 1 An intersection curve with a vertical slope at the maximum abscissa point gives several values of

h (see 6.3.5.2).
NOTE 2 Different values of Y can give different values for h (see 6.3.5.2).
6.3.5 Evaluation criteria for impact surface
6.3.5.1 Criterion for angle α

The angle α should be continuously increased by growing lateral coordinate (y-axis).

The criterion for angle α depends on the lateral position of the evaluation point (see Figure 2: ignoring

transitions and blending):

— Centre zone of impact surface: Surface at the centre of the front end (15 % range of the tram width

in the centre - see Figure 2) should be curved (in order to take into account any design constraints).

This width represents the side-on envelope of a regular-sized human. From the transition point to

the intermediate zone, the angle α should be equal to or more than 15°.

— Intermediate zone of impact surface (lateral position between centre zone (15 % range of the tram

width) and a lateral position of the ± 50 % value of half of the tram width measured from the centre

line): The angle α should be continuously increased to reach equal or more than 30° from the

transition point to the extended impact zone.

— Extended impact surface (lateral position between 50 % and 75 %): The angle α should be

continuously increased (ignoring transitions and blending) from 30° to reach equal or more than 60°.

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6.3.5.2 Criterion for h

In the impact surface the curve of the most advanced points of the impact area (curve of the h points)

should have the lowest Z coordinates possible in order to hit an adult pedestrian below the knees:

h ≤ 350 mm (see also 6.3.3).

If there are several values for h , the lowest h value should be considered/assumed.

s s
6.3.5.3 Criterion for angle β
The angle β should be ≥ 10° over the whole width of the impact surface.
6.3.6 Guiding procedure
The evaluation should be performed according to the following steps:
1) Define the impact surface;

2) Project the front surface to the ground plane (XY) to determine the foremost boundary line for h

and α determination;

3) Determine the evaluation points, e.g. different Y-values for the cutting planes – the evaluation points

should cover the extremities of the impact surface;

4) Determine the values for the angle α in the evaluation points and check the criteria for angle α;

5) Sketch line B in the different cutting planes;
6) Determine d and check the criteria;
7) Determine β and check the criteria.

If these criteria are not met, numerical analyses with ATD models should be carried out to prove

compliance with the criteria or the front design has to be adapted.
6.3.7 Front end geometry
6.3.7.1 Sharp edges and protruding parts

All exposed rigid edges on the extended impact surface (75 % of tram width) and up to a height of

1 750 mm should have radius of at least 10 mm. An edge is considered as exposed only if it can be

contacted by a sphere of 100 mm diameter. In case of pillars that widen towards the top, the requirement

for the absence of sharp ends is valid for the entire range of the impact and extended impact surface

(including the A-pillars).

Any gaps between skirts should be as small as possible. The surface of the A-pillar and/or its cover layer

should be as soft as possible.

Sharp edges should be avoided or covered, e.g. windscreen wiper motor output shaft. Windscreen wiper

arms and blades are excluded. They are considered to be flexible. A rigid edge should be considered to be

one using material with a Shore A hardness greater than 50. For exposed rigid external edges, where the

edge projects not more than 3,2 mm from the adjacent surfaces, the requirements for minimum radii

should not apply, provided that the height of the projection is not more than half its width and its edges

are blunted.
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For the transition between two parts forming a continuous surface (typically transition between two

parts of fairing), the minimum radius of the edges does not apply provided that the gap between the two

adjacent surfaces is less than 20 mm. Edges should be blunted.
Key
R radius 100 mm of sphere
Figure 4 — Transition condition between two parts forming a continuous surface

Coupling elements on trams and light rail vehicles should be covered and the rigidity of their structure

should not represent a risk of aggravating injuries in relation to other nearby structures.

Any rear-view cameras or rear-view mirrors should be positioned higher than 1,75 m.

6.3.7.2 Front window / windscreen

The windscreen at the front window should comply with the requirements of ECE R43 or of EN 15152.

In general, a lower windscreen stiffness is considered favourable, as the risk for severe injuries is

reduced.
6.3.7.3 Tram-surfing
Tram-surfing on the lateral and front surfaces should be impeded.
6.3.8 Summary of recommendations to minimize the severity of pedestrian injuries

This chapter summarizes the recommendations that should minimize the severity of pedestrian injuries.

The following limits for the geometric parameters are recommended:
— β ≥ 10°;
— d ≤ 250 mm.

These parameters should be checked in the cutting planes parallel to the XZ plane in the evaluation points

of the impact surface (see Figure 3).
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Table 2 — Summary of recommendations
Zone considered Recommendation Objective
Front surface of the vehicle no possibility of tram-surfing Avoid tram-surfing
on protruding or external built-
in parts
...

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