2 8 · d e t e k t o r i n t e r n a t i o n a l
Special Feature: Perimeter Security
Train derailments and accidents cost both money
and lives. That is why companies and governments
across Europe are keen to make transport tunnels
safer.
"Modern laser detection sensors can see in com-
plete darkness, strong sunlight, and artificial light,
and are unaffected by the train's bright headlights,
reflections on tunnel walls, or other trains passing
through", says Eelko Griepink, Area Sales Manager
for Benelux and Northern Europe at Optex.
How modern technology safeguards Europe's transport
tunnels
Tunnels are a vital part of Europe's
transport infrastructure, connect
communities, and contribute to
the overall economy and com-
petitiveness of the single Euro-
pean market. And as tunnels have
become more complex, so too
has the technology required to
protect them, according to Eelko
Griepink.
Tunnels are getting
longer and deeper
More transport systems are being
built in underground tunnels each
year in order to reduce the effect
of noise and pollution on people's
lives and the environment. And
these tunnels are getting longer and
deeper. For instance, the tunnel
from Randabreg to Bokn in Roga-
land County, Norway, is 26.7km
long and 392 metres deep under
water, and the Fehmarnbelt tunnel
between Germany and Denmark,
once complete in 2029, will be the
world's longest underwater tunnel
and create a direct corridor from
Northern to central Europe.
"Without these tunnel
networks, economies may falter.
Railway incidents, for example,
can be costly. In December 2023,
a fully loaded iron ore train
derailed at Vassijaure Station near
the Swedish-Norwegian border
on the Malmbanen line, a critical
route for Sweden's largest mining
company, LKAB. The line was not
reopened until 20 February 2024,
but it closed again just days later,
following a second derailment, and
remained closed until early March",
says Eelko Griepink.
This disruption had a signifi-
cant impact, with LKAB reporting
daily revenue losses of 8.8 million
Euro during the closures. Similarly,
when part of the Alpine network,
the Mont Blanc tunnel, closed
following a fire in 1990, the Italian
economy lost an estimated 300 to
450 million Euro per annum until
it reopened three years later.
More than 800
deaths each year
Whilst such large-scale incidents
are rare, smaller ones are not.
European Railway safety statistics
reveal there were 1,567 significant
railway accidents in 2023 with
841 lives lost and 569 people seri-
ously injured. Over half (58.4 per
cent) of fatalities were trespass-
ers typically vagrants (setting
up tents in tunnels), vandals, or
graffiti artists, according to Eelko
Griepink.
Even if there is no injury or
loss of life, vandalism can cause
derailments, collisions and fires, all
of which is costly. In one year alone
there were 3,559 acts of vandalism
and graffiti on Spanish railways, of
which 729 attempts were stopped.
Such incidents cost Spanish Renfe
roughly 25 million Euro annually,
Deutsche Bahn spends 12.1 million
Euro, and Brussels' SNBC around
6 million Euro cleaning graffiti off
rolling stock.
"These incidents are not as eco-
nomically damaging as the Mont
Blanc fire, but show that protecting
the railways and the trespassers is
both expensive and challenging",
says Eelko Griepink.
From CCTV to
smart surveillance
Accurately detecting a person in
the confines of a tunnel is chal-
lenging enough by itself and is
only made more difficult when
several trains are using the tunnels
at the same time.
For around 50 years, CCTV has
been used to monitor tunnel en-
trances and exits. But early systems
needed security teams to constantly
watch between 12 to 24 camera
feeds on a single screen. Thankfully,
video analytics was created and
overcame some of these challenges.
A trespasser will instantly trigger
an alert which directs the security
teams to the appropriate camera
feed, who can then immediately
decide what action to take.
"The technology, though, has
to keep evolving. Trespassers have
learnt that they can go undetected
by moving towards or entering the
tunnel as the train is passing or
deliberately alter their appearance
to fool the analytics software. The
heat and humidity inside tunnels
can adversely affect many older
technologies, and radar or micro-
wave technology struggles to filter
the noise and false alarms generated
by the train, and so they fail to
provide adequate detection", says
Eelko Griepink.
He points out that Optex's
Redscan sensors operate reliably at
temperatures as low as -40°c and
modern laser detection sensors are
unaffected by humidity, tempera-
ture, or lighting conditions.
Eelko Griepink says: "Equipped
with intelligent sensing analytics,
the Lidar technology does not
depend on visible light or thermal
spectrums, which is useful when
tracking a person or animal from
the lit tunnel entrance to inside and
further along the tracks or in the
shadows. They perform remarkably
well even during heavy snowfall
that alters the apparent ground
height and light levels."
Accurate detection
Tunnels located in isolated regions
need accurate detection because
a false alarm is costly in time and
effort if security services are called
out unnecessarily. More advanced
detection sensors, such as Optex's
Redscan series, use dynamic event
filtering to accurately identify hu-
man trespassers.
Eelko Griepink, Area Sales Manager for
Benelux and Northern Europe at Optex.