Hi, Sandro here! Today I'm going to show
you a train that most of you might never have seen in their lives in real life.
That is because it operates in a tunnel, deeply buried in the mountain of Mittagskogel
in the Pitztal valley in Austria. A technology that started out as streetcars in 1873's San
Francisco has evolved into the modern cable cars that are capable of transporting
thousands of passengers a day through arbitrarily difficult terrain and any weather
conditions. In this video you will find out how this technology works, how it's operated
and what happens in case of an emergency. So, what exactly is a cable car? The term is used
for a variety of vehicles, and the terminology is confusing, as it highly depends on the country
you're from. So the cable cars we're looking at today are basically a set of train cars that lack
an engine and that are instead attached to a wire rope that pulls them around. In the US those steel
ropes are called cables, and as they are pulling a train car, the whole vehicle is called a cable
car. The street cars operating in San Francisco have a cable that constantly moves underground.
Each street car can attach to it in order to be pulled along. The cable cars we're going to
look at now though are different, and before we go deeply underground in Austria, let's first look
at this technology in bright daylight. To do that, let's take a quick detour to Zurich and
meet the Polybahn which was built in 1888, just 15 years after the invention of the San
Francisco streetcars. In contrast to those, the Polybahn is built into a single slope. Its
track is never flat. The rope or cable thus only pulls it up, and gravity makes it roll back down.
Such cable cars are called funiculars, and they are the dominant kind of cable cars today.
Well, so much for the theory, but let's make this a little bit more tangible. What exactly is
a funicular, and how does it work? To illustrate this, I printed two train cars that I found on
Thingiverse. At their current configuration, they're just two regular train cars, happily
choo-chooing along the rails. It's time to make a serious modification. We're now going to attach
a thread to the car. This threat is symbolic for the - ouch - steel wire cables the funicular cars
are attached to. And the other end of the thread, you probably guessed it, we're going to attach
that to our second car. With these modifications being complete, it is now time to assemble our
funicular. With that, we'll need a drive pulley and a shaft. The shaft goes into the pulley,
and then both are attached to the top station. And last, but not least: an electric motor. And
just like that, we have completed our model of the funicular. As you can see, this kind of works
like a diagonal elevator, where one car is the counterweight of the other. The cars themselves
are unpowered. There is a single motor in the top station that moves the whole system, and whenever
one car moves, so does the other. And that is how a funicular works. And this is what an actual
funicular's drive pulley looks like. Of course, real funicular cars operate on rails, and their
path doesn't necessarily have to be a straight line. Pulleys are used to make the rope follow
the tracks. As the rope's length varies with the amount of passengers, as well as the current
temperature, the bottom station is equipped with bumpers which ensure that the car on the rope's
long end still stops at its intended endpoint. An intriguing detail is that the two cars share the
same track at the stations. But they flee to their own track section for crossing each other in the
middle. Each car seems to magically find the track it belongs to, and they never collide. So, what is
this 19th century sorcery? Looking at the switch, we can see that the two outermost rails are simple
and uninterrupted. In contrast on the inside, there's just a jungle of rails. Looking closely at
how a car passes the junction, we can see that it follows closely the outer rail while apparently
ignoring the inner ones. But wait! The inner wheel is just a drum. It simply supports the car's
weight, while the other wheel is shaped something like this. The shape forces it to follow the rail
upon which it is placed. So each car will take the side on which the shaped wheel is placed,
thus taking the correct track every time it passes the switch. Knowing these basics, we can
now make our way to the Pitztal in Austria. Oh, hi Marcus! This ordinary looking building houses
the bottom station of a funicular that is a much more modern version of the Polybahn. The
construction of the tunnel of the original trains was completed in 1983. But the trains
have just been replaced in 2022. These bad boys can transport 1620 people per hour through an
altitude difference of 1111 meters. The tunnel is 3.6 kilometers long and has a fixed switch in the
middle, just like Polybahn. Both can be remotely controlled. However, during normal operation,
the Pitztal express is operated manually. At the top station we meet one of the operators.
Like most people featured on this channel, his name is Michael, and he's a super chill dude.
Before departure, Michael checks the cameras and closes the gates that split the waiting crowd
into groups the funicular can transport. The ride is closely monitored by a multitude of
sensors in- and outside the vehicle. A retrofitted wi-fi system provides a gapless network through
which telemetry, communications and camera live feeds are transmitted. We are now arriving
at the bottom station, which is the counter station. It is called that way because the
propulsion system is located at the top station. Even though the weight of the cars is
pulled by the steel cable from above, there is a second wire rope, connecting
the bottoms of the trains as well. This way they are linked to the red counterweight
card that keeps the long steel ropes under constant tension. Any tension spikes are canceled
by it by moving up and down on the lowest portion of the rail. The trains are unpowered and their
batteries are charged at the stations. However, with all the electronics inside the car, that
is not enough to keep them charged on days with high demand, where the trains only spend a short
time at the stations. The new trains, installed in 2022, are equipped with a generator that
charges the batteries while the train is moving, a novelty that proved to work reliably. But how do
you actually replace a train that operates inside a mountain? The answer is by removing this plate
off the bottom station including the wall with that door. The process was filmed, and there is a
cool two minute video about it. I'll put the link in the description. But now it's already time to
ride back up. Cumulating the altitude difference, Michael and his colleagues ascend Mount
Everest multiple times a day. Even after the just five rides I took for this video, I felt
exhausted by the ongoing change of the atmospheric pressure. Working here as an operator is
not for cowards. We are now traveling up to an altitude of 2840 meters.
The journey takes 8 minutes. The mountain keeps the tunnel
at a constant temperature, causing the air to become foggy. To
counter this, the entrance is sealed while the train is underway. The air pressing
through the door produces an uncanny song. There is something unsettling about
hurtling up the steep incline of this dark never-ending pipe. Just the slightest
memory of the story of a terrifying incident in a similar cable car in Kaprun in the year
2000 sends goosebumps down my neck. There, an undetected fire had started in a similar
cable car, quickly spreading and causing the funicular to fail and stop midway. 150
people died, trapped in the tunnel. Luckily, many countermeasures have been taken to prevent
something like that from ever happening again. So, in case of a fire, the funicular speeds up
to its limit, and some sensors are disabled to get the passengers out in any case, as fast as
possible, even if the fire starts destroying electronics inside the train. Another of the
elements to look out for is water. The tunnel is equipped with a sophisticated drainage system.
But the trains are still exposed to water from the mountain, dripping down from the ceiling. For
this reason, the top station's tunnel entrance is equipped with a car wash which sprays and
dries the trains whenever they need a washdown. Whenever the infrastructure in the tunnel
needs to be serviced, the lights are turned on, and the workers are brought to the location with
the train. In rare cases, they can also take the stairs which consist of literally breathtaking
11'000 steps. To avoid that passengers have to walk this in ski shoes in case of a technical
problem, the funicular can operate in three extra propulsion modes. To learn more about them,
let's first talk about the drivetrain. Meet Heiko, the chief engineer of the Pitztal express. He
has huge knowledge in many different fields, and we're about to find out why. Interestingly, the
Pitztal Gletscher domain has its very own 30'000 Volt high voltage line, going directly into
their station. And they transform it down to 400 Volts themselves, also for the restaurants. The
high voltage is passed from the bottom station. The funicular becomes a generator itself in the
late afternoon, when significantly more people are transported down than up, their weight
generating electrical power. Overall however, the cable car consumes a yearly average of
four and a half to five GW of electricity, as much as 1'000 households. Part of that
energy is coming from solar panels on the mountain. Their power output is also converted
to 400 Volts and feeds the local power grid back to a few nuclear components. The 400 V is
then applied to four sets of controllers, one for each motor. This is where the electricity is
converted to DC. I won't go much more into detail, because I have covered this technology already on
an earlier video about the Gondelbahn Flaschen. The DC power is then applied to the motors.
There are four in two groups, and each motor has 340 KW or 462 horsepower. In 2018 the entire
controlling system was replaced and modernized. The torque of all four motors is then applied
to the main disk which is also where the series break and the security break are located.
The security break is usually kept open, and this is a service break that closes when
the regular stopping point has been reached. Wow, what a show! The wire rope
passes the drive pulley twice, preventing it from slipping. So what exactly
happens if a motor or gearbox fails? Remember that the drivetrain consists of two motor groups,
each driving the pulley through its own gearbox. Between those two gearboxes and the pulley are
clutches. If a group fails, it can be decoupled, and the cable car remains operational,
but it will run at only half the speed. So much for the first alternate propulsion mode.
This wouldn't work in case of a power outage. In that case, those two 12-cylinder diesel motors
coupled through generators are used. Each motor is equipped with two generators, one producing DC for
the cable car and the other generating three-phase current for the lights and the drinking water
pumps. Each motor can output 462 horsepower, meaning that both combined can drive
two of the cable car's motors which can then operate at the half speed mode using
diesel fuel. To see the last emergency mode, let's go up to the control room
with Michael! Oh, hello there! They really engineered this system for
robustness. The reason is that there is no road leading up to the mountain in the winter
time. Even the transport of goods has to be made with the cable car by attaching this special
trailer. To make this possible, the steering system has an extra slow crawling mode, where
the cable car moves at a barely noticeable speed, even slower than in this shot. Filming and editing
these videos takes me several hundred hours. I'm not affiliated in any way and I'm not getting
paid by any of the places I film. So if you would like to support my independent work, please
consider becoming a patreon. I put the link down in the description. It will be much appreciated,
thank you very much! So, that's it for today, thank you very much to Michael and Heiko for
showing me around, explaining me everything, and also a big thank you to the Pitztaler
Gletscherbahn, who again allowed me to come this year and film the heck out of their ski domain.
It's always a great pleasure of working with you, So, so long for today, thanks for watching and
have a great day, maybe see you in the next video.
