Tunnel safety concept for the new railway line Divača - Koper - DRC

Tunnel safety concept for the new railway
line Diva a - Koper
Dr.Dipl.Ing. Rudolf Bopp
Gruner, ZT GmbH, Wien; Austria
Angelo Žigon, univ.dipl.inž.grad.
Marko Žibert, univ.dipl.inž.grad.
ELEA-iC, Ljubljana
Abstract
The new railway line planned between the city of Diva a and the port of Koper is characterised
by a sequence of tunnels and viaducts separated only by short stretches of open line. Due
to the high proportion of tunnels and the difficult access to the line particular attention must be
paid to the development of a safety concept.
The paper focuses on tunnel safety concept for the railway line on subsection rni Kal –
Koper which is designed and will be executed as a 1st stage of the new railway line. Nevertheless
the paper gives a short overview of the whole project. The main infrastructural safety measures
such as the escape routes and the rescue areas near the portals are described. As an example of
a technical safety measure the tunnel ventilation concept is presented.
Keywords: Tunnels, Safety concept, Safety in tunnels, Railway, V. corridor
Povzetek
Zna ilnost novega odseka železniške proge med Diva o in pristaniškim mestom Koper je
zaporedje predorov in viaduktov, ki jih lo ujejo kratki odseki odprte trase. Glede na velik delež
trase, ki poteka v predorih in težko dostopnost je potrebno posebno pozornost nameniti izdelavi
varnostnega koncepta.
Prispevek se osredoto a na predstavitev koncepta za pododsek rni Kal – Koper, ki je v
terminskem planu izvedbe postavljen v 1. fazo, hkrati pa podaja kratek pregled celotnega projekta.
Opisani so vsi pomembnejši infrastrukturni varnostni ukrepi kot so ubežne poti, reševalne
površine in postaja na portalnih obmo jih.
Kot primer tehni nega varnostnega ukrepa je predstavljena zasnova prezra evanja.
Bopp, R., Žigon, A., Žibert, M.: Koncept varnosti v predorih za novo železniško progo Diva a - Koper

1 Introduction
Bopp, R., Žigon, A., Žibert, M.:
Tunnel safety concept for the new railway line Diva a - Koper
Port of Koper is one of most important
centers of logistics and freight transportation
in Slovenia. In year 1967 the new single track
railway line was opened to connect flourishing
port with middle European cities. After
1990 the business growth almost tripled and
with more ambitious projects ahead a need for
a higher capacity railway line was evident. A
new single track railway line between Koper
and Diva a was proposed in a corridor which
is a:
part of V. pan-European transportation
corridor Venice – Kiev and
part of VI. trans-European transportation
corridor Lyon – Budapest
Since the negotiations with Republic of
Italy over the alignment of new railway
section were not finished in time the client
(Government of Republic of Slovenia - Ministry
for Transportation) decided to move
ahead with first stage from Koper to rni Kal
which probably will not be part of the main
corridor.
This new high capacity railway line will
run predominantly through tunnels. As safety
measures may greatly influence the tunnel
design, tunnel safety aspects must be considered
in an early phase of the project and some
fundamental decisions have to be taken. As
these decisions influence not only the safety
but have also wide impacts on the construction
and operation costs of the new railway
line a close examination is necessary.
Figure 1: Location of the railway line regarding pan-european and trans-european corridors
The paper gives first some information
on the relevant guidelines for tunnel safety
and the approach for the development of a
tunnel safety concept. In a second part the
most important safety measures which have
been decided for the Diva a - Koper project
are described.
2 Project overview
2.1 General description
In order to cope with immediate ascent
of the terrain in Koper hinterland the alignment
of the high capacity railway line travels
rather through tunnels in constant gradient
than in many twists on open section like the
existing line.
The whole section of railway line alignment
from Koper to Diva a is characterized
by two distinctive subsections (see Figure 2).
The first section with 6 tunnels and two long
viaducts leads from Koper to rni Kal with a
length of 12.135 km where alignment gains
height traveling just under the surface on the
slopes of Tinjan hill in big circular section
and ends with crossing Osp Vally with long
viaduct. The second section from rni Kal to
Diva a with a length of 15.061 km travels
through 2 deep long straight tunnels in karstic
region. Only the first section will be described
in further text.
More than 7.5 km out of 12.1 km of the
railway line from Koper to rni Kal travels
through tunnels. The distance between portals
of consecutive tunnels in the upper part of this
section is very short. Tunnels T3 to T7 must
therefore be considered as one long tunnel
(see also Table 1)
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Bopp, R., Žigon, A., Žibert, M.:
Tunnel safety concept for the new railway line Diva a - Koper
Figure 2: The general layout of the railway alignment
Figure 3: The longitudinal profile of the railway line
Table 1: Description of the tunnels on subsection Koper – rni Kal
Tunnel Length Tunnel Set Start Ch. End Ch. Length of
tunnel set
T3 330 m
T4 1947 m
T5 115 m 1 16+760,000 21+020,000 4360 m
T6 335 m
T7 1150 m
T8 3760 m 2 22+280,000 26+040,000 3760 m
2.2 Description of a typical
tunnel
Typical tunnel on the new railway line is
a single track, single tube NATM tunnel
consisting of primary shotcrete lining, waterproof
layer and cast in place concrete lining.
Typical inner dimension of horseshoe like
form of normal cross section is width/height
=6’7m/7’0m, designed around demanded
modified GC train clearance profile (see
Figure 4). With a possible future second tube
in mind the cross section is designed as
symmetrical thus track (width=3’40m) is
positioned in the axis of the tunnel with raised
emergency walkway (width=1’65m) located
on both sides. Bellow walkways the space for
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Bopp, R., Žigon, A., Žibert, M.:
Tunnel safety concept for the new railway line Diva a - Koper
supply and telecommunication cabling is
provided.
The track structure is designed as a slab
track system sitting on tunnel invert concrete.
Table 2: Overview of traffic characteristics
2.3 Operation of the new line
The railway line will be used mainly by
freight trains climbing the ascent from the
port of Koper towards Diva a. Nevertheless
the railway line is designed for both freight
and passenger trains (see Table 2) in both
directions driving in bundles of 3 to 5 trains.
Type Number Length of train
(max./average)
Vmax Notes
IC/EC 3 pairs of trains/day 400 m/250 m 160 km/h
Pendolino 2 pairs of trains/day 82 m/82 m 160 km/h
Freight trains direction 45 (fully loaded) or 750 m/500 m 120 km/h Ro-La
to Koper
57 (dynamic ut. )
Freight trains direction 50 (fully loaded) or 750 m/500 m 80 km/h Ro-La
to Diva a 63 (dynamic ut. )
In accordance with TSI RST HS only
trains category B shall be used in passenger
traffic on the new railway line. This category
demands that in case of fire the train is capable
of driving at least 80km/h for next 15
minutes ignoring emergency brakes and
maintaining means of communication.
Currently a 3kV DC (direct current) supply
catenary system is planned. In future a
25kV 50Hz AC system is foreseen.
Figure 4: Typical NATM tunnel cross section
3 Guidelines
3.1 European and national
guidelines
The main risks in railway tunnels are
fire, collision and derailment. As a fire in a
passenger train is a major and specific hazard
in tunnels with potentially catastrophic consequences,
discussions about tunnel safety
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Bopp, R., Žigon, A., Žibert, M.:
Tunnel safety concept for the new railway line Diva a - Koper
often concentrate on this type of incident.
However this limited perception must be
abandoned when a safety concept for a railway
line as the Diva a -Koper line is developed.
The elaboration of a tunnel safety concept
is a quite complex task where an important
number of aspects and subsystems must
be considered. There are however only few
guidelines on safety in railway tunnels which
can be consulted. The most important are the
technical specification of interoperability
relating to ‘safety in railway tunnels’ in the
trans-European conventional and high-speed
rail system, the so called TSI SRT 0. These
relatively new specifications define for a first
time a minimal safety standard for railway
tunnels in Europe. However TSI SRT specifies
only few mandatory safety measures.
In addition to the safety measures specified
in the TSI SRT, the guidelines of the UIC
Codex 779-9 0 concerning tunnel safety
should be considered. The UIC document
gives a good overview over a more general
set of possible safety measures and provides
additional information concerning the efficiency
of different safety measures.
Along with the European guidelines
there are a number of national guidelines as
for example the German EBA guideline 0 or
the Swiss guideline SIA 197 0, 0. In Austria
the guideline of the national fire fighting
association has to be considered 0. These
national guidelines ask to some extent for
additional safety measures and they often do
specify the needed measures in more detail.
This may lead to a different set of safety
measures when different national guidelines
are used (see examples in chapter 3.3).
In the absence of national guidelines and
lack of most recent national experience in
railway tunnel safety, as it is the case in
Slovenia, the development of a specific
railway tunnel safety concept is therefore a
long process which has to involve a various
authorities (see chapter 4.2).
3.2 Application of guidelines
In the application of the different guidelines
the following problems may appear:
National guidelines are normally
stricter than the regulations of the TSI
SRT.
When comparing different national
guidelines different safety measures
may result.
3.2.1 Comparison between TSI
SRT and national guidelines
The most important infrastructural safety
measures specified in the TSI SRT are:
Escape distance: The maximum distance
of cross passages (in double bore tunnels or in
tunnels with a parallel service and safety
tunnel) or distance of emergency exits in
single bore tunnels is stipulated in the TSI
SRT (maximum 500 m for tunnels with a
parallel tube or maximum 1000 m for a
double track tunnel).
Escape walkways: Lateral walkways
inside the tunnel with a minimal width
of 0.7 m must be provided.
Rescue areas at tunnel portals: In the
vicinity of the tunnel portals enough
space for the deployment of the rescue
services is needed. The TSI SRT defines
a minimal area of 500 m 2 .
The fact that some of the very long
double bore tunnels planned or built in
the last years, have considerably lower
distances between cross passages (see
table 3) shows that in the application of
the TSI SRT and national guidelines
different solutions may result. This is
not only true for the distance of cross
passages but also for the width of the
escape walkway which is normally
bigger than 0.7 m or the rescue areas at
portals which are normally considerably
larger than 500 m 2 as stipulated in
the TSI SRT.
Table 3: Distances of cross passages in long railway tunnels
Tunnel Length Cross passages Special features
Channel Tunnel 50.5 km 375 m lorry transport
Lötschberg Base Tunnel 34.6 km 333 m underground emergency station
Tunel de Guardarrama 28.4 km 250 m
Great Belt Tunnel 8.0 km 250 m underwater tunnel
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3.2.2 Comparison between national
guidelines
Consulting different national guidelines
may lead to contradictory recommendations
as the following examples show:
Water supply for fire fighting: In Germany
dry water pipes in all tunnels
longer than 500 m are mandatory
whereas in Switzerland normally rescue
trains (mobile water supply) are
used and no fixed water pipes are foreseen
in railway tunnels. In Austria permanently
filled or dry pipes are demanded.
However in very long tunnels
as the 32.8 km long Koralmtunnel 0 or
the 27 km long Semmering-Base Tunnel
0 the water is brought into the tunnel
by a rescue train and a fixed water
supply system is planned only in the
underground emergency station.
Ventilation: Another example is the
ventilation of cross passages which
connect two parallel tunnel tubes. Ac-
Professional
Qualifications
Maintenance
Rules
Operation
Rules
Health &
Safety
Conditions
Tunnel
Safety
Bopp, R., Žigon, A., Žibert, M.: Koncept varnosti v predorih za novo železniško progo Diva a - Koper
cording to the German EBA guideline
airlocks without any mechanical installation
to prevent a propagation of
smoke to the parallel tunnel tube (safe
area) are possible, whereas in Austria a
mechanically generated overpressure is
requested.
4 Approach to develop a
safety concept for a
railway tunnel
4.1 Subsystems
Although in tunnel projects major focus
is put on infrastructural safety measures it has
to be pointed out that tunnel safety depends
not only on infrastructural measures but on a
bigger number of subsystems. Figure 5 gives
an overview over these subsystems. All of
them are equally important and have to be
considered in the development of a tunnel
safety concept.
Rolling
Stock
Infrastructure
Energy
Figure 5: Subsystems relevant for railway tunnel safety according to 0
4.2 Basic principles
Although there is no generally accepted
state of the art for tunnel safety some generally
agreed principles do exist. So the design
of a tunnel must allow the self-rescue and
evacuation of train passengers and staff.
Furthermore provisions for the rescue services
to rescue people in the event of an
incident in a tunnel shall be provided. Appropriate
safety measures should be considered
when a tunnel safety concept is developed.

Bopp, R., Žigon, A., Žibert, M.:
Tunnel safety concept for the new railway line Diva a - Koper
According to 0 and 0 there are the 4 following
categories of measures which can be
discerned:
Prevention of incidents,
Mitigation of impact of accidents,
Facilitation of escape,
Facilitation of rescue.
The order in which these categories are
listed reflects their decreasing effectiveness to
Safe side
Risk in tunnels
Prevention
A safety concept generally consists of a
combination of infrastructure (civil and
technical), operations and rolling stock measures,
which should be combined in a manner
to achieve an optimised concept. The definition
of specific safety measures in a project
should be based on an assessment of the risk
(risk based safety concept).
4.3 Safety management
group
Mitigation
There is not only a big number of subsystems
which must be considered in the
elaboration of a safety concept, but also the
different stakeholders involved in the planning
process (national authorities, the owner,
the designer of the tunnel and the technical
installations, contractor(s), operator, emergency
services as fire fighters). It is therefore
recommended that a safety concept is developed
in a safety management group 0 which
goes along with the project over all project
phases. The safety management group will
normally be a "living structure/organism"
which has to adapt to the changing needs
during the different phases of the project.
Figure 6: Hierarchy of safety measures
reduce the risk in a railway tunnel (see Figure
6). It is important to note that measures preventing
an incident in the tunnel (e.g. emergency
brake neutralisation during a tunnel
passage) are much more effective than measures
which improve the self rescue (facilitation
of escape) of passengers or measures
which support the rescue services (facilitation
of rescue). The strength of railways lies in the
prevention of accidents.
Evacuation
Rescue
Residual
risk
One of the very important tasks of the
safety management group is the definition of
specific (quantitative or qualitative) safety
goals. The instruments to check the achievement
of these safety goals and the methods to
assess the (residual) risk should be defined.
Furthermore the key decisions should be
systematically recorded and the contents of
the safety documents for the procedure of
approval by the authorities as well as the
documents, which will be used in the operation
phase, should be defined in an early stage
of the project.
5 Key elements of the
safety concept rni Kal
- Koper
5.1 Infrastructural safety
measures
In the early phase of the project the infrastructural
measures had to be defined as a
basis for the planning of the tunnels. The
most important measures are:
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Bopp, R., Žigon, A., Žibert, M.:
Tunnel safety concept for the new railway line Diva a - Koper
5.1.1 Tunnel system
Single track tunnels: All tunnels are
single track, so that there are no
switches in the tunnels. The risks associate
with train crossings and derailment
are thus reduced.
Escape routes: Special lateral escape
galleries in longer tunnels (T4, T7) will
be built. The maximum distance between
to escape galleries is 660 m. For
the longest tunnel (T8) a parallel safety
tunnel with cross passages to the railway
tunnel every 500 m is planned. In
the railway tunnels on both sides a lateral
walkway is available. The width of
the lateral walkway is 1.65 m and the
walkway on the side which leads to the
escape galleries / cross passages is
equipped with a handrail.
Fire protection for structures: The
zones where tunnels cross critical infrastructures
as the highway Koper -
Ljubljana with low overburden special
reinforcement of the tunnel structure is
foreseen to guarantee the stability of
the tunnel for a sufficient time in the
case of a fire in the tunnel.
Collection of water and liquids: In addition
to the drainage system to collect
the rock water, a separate de-watering
system is foreseen in the tunnels to
drain forge water or toxic liquids in
case of a spillage of dangerous goods.
These liquids are collected by a separate
drainage tube which is equipped
with siphons in regular intervals and
which is connected to a retention basin
at the lower tunnel portal.
5.1.2 Emergency stop area
The probability that a burning train can't
reach the portal (safe area) increases with
increasing tunnel length. Therefore, according
to TSI SRT "appropriate provisions must be
laid down to take account of the particular
safety conditions in very long tunnels". As the
Diva a - Koper line consists of a continuous
succession of tunnels and viaducts there is no
natural place, where a train could be stopped
and evacuated in the case of a fire. The situation
is thus comparable with a very long
tunnel.
In the case of a train fire a modern passenger
train should maintain its movement
capability for 15 minutes 0. Assuming a train
speed of 80 km/h a train can thus travel a
distance of about 20 km. Therefore in tunnels
which are significantly longer than 20 km
normally an emergency station is foreseen,
where a tunnel can be stopped and evacuated
0, 0. This safety measure which can drastically
reduce the severity of a train fire is also
implemented in the Diva a - Koper project.
At km 16.1, which is approximately in
the middle of the section with the 8 tunnels an
emergency stop area is planned at the lower
portal of Tunnel T2. A platform with a length
of 400 m allows a fast and safe evacuation of
a train. Due to the limited space a part of the
platform will be located on the viaduct. The
area is equipped with lighting, communications
facilities, video control, etc and can be
accessed by road vehicles.
5.1.3 Portal areas and access
to tunnels
The roads which are built for the construction
of the tunnels will serve as access
roads to the tunnel in the operation phase.
Despite the mountainous area each tunnel
portal can be reached by road vehicles. Totally
6 portal areas with a surface of minimum
1500 m 2 and 7 portal places with a surface of
minimum 500 m 2 are available for emergency
services.
The slab track is not trafficable by road
vehicles. Access into the tunnel is ensured by
two way vehicles (road - rail) of the fire
fighters. Additionally rolling pallets for the
transport of injured passengers and material
will be available at the portals of the tunnels
and the escape galleries.
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Bopp, R., Žigon, A., Žibert, M.:
Tunnel safety concept for the new railway line Diva a - Koper
Figure 5: Typical section of layout for safety concept showing rescue areas, equipment provided, emergency
routes for rescuers and time prognoses,….
5.2 Technical safety measures
Beside the infrastructural safety measures
a big number of technical safety measures
are planned. The most important are
given below:
5.2.1 Ventilation
Whereas longer road tunnels are generally
equipped with a mechanical ventilation
system, railway tunnels normally do not have
a mechanical ventilation system because there
is no exhaust from combustion engines which
has to be removed from the tunnel. If railway
tunnels are equipped with ventilation system,
the primary goal is to guarantee smoke free
areas (a safe area according to TSI SRT). This
is normally achieved by a positive pressure
compared to the incident tube. It has to be
noted however, that it is not state of the art to
use the ventilation in rail tunnels to control
the smoke movement in the incident tunnel
itself.
In the Crni-Kal section of Diva a - Koper
project the following ventilation system
are planned:
Ventilation of service tunnel (T8): The
3.8 km long tunnel T8 has a parallel
service tunnel with ventilation buildings
on both sides. A mechanical ventilation
system is needed to remove the
waste heat of the technical equipment
which is placed in technical rooms
which are located in the cross passages.
Additionally the ventilation system
must guarantee a sufficient airflow
through open escape doors in the case
of a fire.
The fans, which are located at both portals
of the service tunnel, bring air into
the service tunnel to generate an overpressure
to the railway tunnel. On both
sides 2 fans are foreseen, so that even
in the case of one fan failing, still more
than 75% of the maximum airflow can
be delivered. This partly redundancy is
important because the waste heat has to
be removed permanently from the tunnel
to guarantee a safe operation of the
technical equipment.
In each of the 7 cross passages a door is
foreseen separating the railway tunnel
from the safe area. To maintain the
overpressure in the parallel service tunnel
during self rescue and access of
rescue services both portals are
equipped with an airlock.
Ventilation of escape galleries (T4,
T7): As there is no need to remove
waste heat from technical installation in
the escape galleries in normal operation
a simpler ventilation system is possible.
The escape galleries of tunnels T4 and
T7 are equipped with an air lock which
is situated at the exit of the escape gallery.
At the other end of the escape gallery
an escape doors separates the safe
area from the railway tunnel. Above the
airlock a single fan is foreseen which is
able to provide an airflow through the
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Bopp, R., Žigon, A., Žibert, M.:
Tunnel safety concept for the new railway line Diva a - Koper
escape door which is high enough to
prevent smoke penetrating in the escape
gallery.
5.2.3 Measures to facilitate rescue
Table 4: Safety measures to facilitate self rescue
5.2.2 Water for fire fighting
All tunnels are equipped with hydrants at
a distance of 125 m. The water pipe, which is
permanently filled, is supplied by 3 basins
with a volume of 200 m 3 each. A pressure
between 6 and 12 bar is assure at all points
and 800 l/min can be supplied.
Measure Remarks
Emergency lighting Illuminated walkway (minimum 1 lux) and escape
galleries, brigther illumination of escape doors
Escape signage illuminated signs at a distance of 50 m on escape walkway,
reflecting signs between the illuminated signs
Table 5: Safety measures to facilitate rescue
Measure Remarks
Segmentation of overhead line segment < 5 km (details still to be defined in a later
project phase)
Earthling devices for overhead line details still to be defined
Electricity supply 230V / 400V power sockets at distance of 125 m
Communication
radio for emergency services
2 Way vehicle to facilitate access to based in Koper
tunnel
Rolling pallets at portals of main tunnels and at portal of escape galleries
5.3 Operational safety measures
and train safety
Beside the infrastructural and technical
safety measures also the trains and the operational
procedures do have an important impact
on the safety level. Passenger trains of
category B will be used. Actually there are no
restrictions for freight trains and/or transportation
of dangerous goods foreseen. Further
studies, especially on the transportation of
dangerous good should be undertaken in the
next project phase.
In the case of an emergency situation fast
operational action is needed. Only few decisions
and relatively simple operational measures
are necessary in the case of a train fire.
The most important operational measures in
an emergency situation are:
Trains following the emergency train
are stop immediately. Whenever possible
it should be avoided that two trains
are in a tunnel.
Trains in front of the emergency train
continue their journey.
The emergency train itself should not
stop inside a tunnel. The train tries to
reach the emergency stop area resp. to
the end of the line.
The detail operational procedures in a
case of an accident will be specified in a later
phase of the project.
References
TSI SRT, "Safety in railway tunnels in the trans-
European conventional and high-speed rail
system", 2008/163/EC
UIC leaflet 779-9, Safety in Railway Tunnels,
August 2003
Anforderungen des Brand- und Katastrophenschutzes
an den Bau und den Betrieb von Eisenbahntunneln,
Eisenbahn Bundesamt,
1.07.2008
SN 505 197, SIA 197, Projektierung Tunnel,
Grundlagen, SIA Zürich 2004
SN 505 197/1, SIA 197-1, Projektierung Tunnel,
Bahntunnel, SIA Zürich 2004
ÖBFV-RL A12, "Bau und Betrieb von neuen
Eisenbahntunnel bei Haupt- und Nebenbahnen,
Anforderungen des Brand- und Katastrophenschutzes"
Richtlinie, Österreichischer Bundesfeuerwehrverband,
Ausgabe 2000
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Bopp, R., Žigon, A., Žibert, M.:
Tunnel safety concept for the new railway line Diva a - Koper
Bopp, Burghart, Harer, Koinig, Neumann - "Incident
management in a very long railway tunnel",
3rd International Symposium on Tunnel
Safety and Security, 12-14 March, Stockholm,
Sweden
Bopp, Langer, Neumann, Wagner, The ventilation
and tunnel safety concept for the New Semmering
Base Tunnel, Südbahntagung, Leoben
2009
Long Tunnels at great depth, ITA working Group
no 17, ITA Report No 004, April 2010
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