- The Gotthard Base Tunnel
is the longest and deepest rail tunnel in the world,
57 kilometers through the Alps.
Literally, through. It's called a "base tunnel"
because it's at the base of the mountain.
At its deepest point, there are more than two kilometers of rock above.
It's so far down into the ground that the earth in there is hot.
Without ventilation, the air temperature will be more than 40°.
Around the turn of the century,
there were two devastating fires in road tunnels under those mountains,
and the authorities here in Switzerland
want to make sure that nothing like that can ever happen again.
How they do that is fascinating.
So here's what's going to happen.
We're going to see the control center that watches over the tunnel,
and also visit one of the intervention centers,
with the firefighters and first responders
that'll step in if the worst were to happen.
And then I want to show you what I reckon is the most
important bit of safety equipment.
It isn't anywhere near the tunnel,
and most people will probably never notice it.
But before that, we start at the control center,
just over there.
- In the Gotthard Base Tunnel, there are
six freight trains and two passenger trains, per hour, per direction.
This means that at the same time, there are several trains
inside the tunnel, in both of the two tubes.
The Gotthard Base Tunnel is divided into three thirds.
If there is a disturbance in one of these thirds,
the train can be diverted at one of the two changement points,
into the other tube, to bypass the disturbed section.
There are different sections to control the traffic.
The signal box controls the track.
The movement authority is given by the signal box,
and by the traffic controller.
If there is a disturbance on one of the systems in the tunnel,
then we have different possibilities.
First of all, we get noticed by an alarm that there is a problem.
They first of all try to fix the problem remotely.
If this is not successful,
they can send people on site to try to fix it.
- This tunnel is actually a bit of a tourist attraction in itself.
You can get driven in, down the service tunnel,
on a guided tour, and end up at this reinforced, windproof, visitor's window
with 8cm-thick glass, and watch the trains go by
at anything up to 230km/h.
That was terrifying!
- If a train has a technical problem, first of all
the train driver tries to reboot the train system.
If it's not successful, we have the firefighting train,
which goes into the tunnel to tow out the broken train.
In case of an incident in the tunnel, let's say a fire,
we have two intervention centers, North and South.
"Intervention center" means firefighting stations.
They get an alarm, and within five minutes,
usually both of the firefighting trains
go into the tunnel from north and from south
at the same time to fight the fire.
They have the obligation to be on any point in the tunnel
within 45 minutes.
Firefighting train is a convoy of firefighting trucks on rail.
They bring water in, foam liquid. They bring special equipment, tools,
to handle any possible situation inside the tunnel.
At the two emergency stops,
there is a possibility to refill their water.
If people have to be evacuated in the tunnel,
they do not walk out of the tunnel because it's much too far.
The train brings them to one of two evacuation stations,
where the passengers can go into the evacuation tube.
This evacuation tube is under pressure, so fresh air is streaming in.
They are safe because they have enough oxygen,
and smoke cannot enter.
Then they go to the next evacuation section,
where the evacuation train is waiting for them.
We have to be able to evacuate the entire tunnel
within 90 minutes.
- As I went round today, one of the team said
that if there ever is an evacuation or a fire in the tunnel,
several other things had to go wrong first.
Yes, you can never protect
against every possible weird circumstance, but you can try.
Which brings me here,
to what's basically the middle of nowhere in Switzerland,
about 15km away from the south entrance to the tunnel,
and to this gantry over the tracks.
15km sounds like a lot, but at the speed Swiss trains can travel,
that could be about four or five minutes.
And while it doesn't look like much,
this gantry scans every train, at speed, before it even gets near the tunnel.
There are sensors on the track around here too,
and if the train has anything unbalanced, any hot spots that look out of place,
anything poking out, then it's not going into the tunnel.
- We have laser systems which measure the profile of a train.
Maybe the load of a train has moved,
and doesn't respect any more the necessary profile to enter a tunnel.
We have heat detection, where we can detect
overheated axles or overheated brakes.
All these controls, they happen at usual commercial speed
of the trains, in different points, all over Switzerland,
and we get about 200 alarms per day from these measuring stations.
If we do not confirm an alarm within 30 seconds,
the train is stopped automatically.
It's not an emergency stop, it's... but it's quite... you feel it!
If a train seems to be wrong,
it gets to a side track where it has to wait.
If the inspection says, this train is okay,
then it can continue its journey,
if not, the owner of the train has to resolve the problem
before the train can continue its journey.
- Yes, there are lots of systems in place for if "the worst happens",
but prevention is better than cure,
and for me, this gantry is the most important bit
of safety equipment here,
because the best solution is to stop problems
before they even start.