5:15am - The next workstep after the initial system check is
inspecting the track. The computer hasn't reported any anomalies
during the boot process, and now the visual control of the wearing
parts and the security related components begins. These daily
routine checks are only a part of the complex inspection
procedure. So for example the cars are deconstructed after a
specified amount of load cycles to examine the highly stressed
components with ultra sound to find micro-cracks inside the
material. In addition, TÜV as an independent service
provider is consulted once a year for an exhaustive test. There is
a huge responsibility on the shoulders of the manufacturer as well
as the owner, and they perform uncountable safety measures to meet
the demands. This controlled thrill makes roller coasters the
safest means of transportation at all.
at a block brake
But back to the inspection of the track. To check all components
one after the other, the system is switched to a special manual
operation mode for the time of the maintenance works. The focus
lies on brakes, sensors and the complex special effects. Team
leader Werner Kuhl is already on his way, we will meet him
later on. Like all staff members, he keeps contact with his
colleagues in the control room via voice radio.
The first task is the check of the brake systems. Like every
modern roller coaster the two Winjas are based on a block
system that allows operation of up to six cars per side. Every
course is divided into eight sections to achieve that, and every
transition point is equipped with so-called block or check brakes.
To prevent collision accidents, there may never be more than one
car in each block. The control unit with its body of rules assures
that the brakes in front of a block only open when the sensors at
the end of the section report that the previous car has passed and
the block is empty. So there is always at least one brake section
between two cars so they can be be securely stopped.
The brakes at Wuze Town use the principle of Coulomb
friction. At the underbody of the cars there is a metallic brake
fin that has a special coating on both sides. The active part of
the brake is mounted to the track: These brake modules are more
than one meter long and have a gap in which the fin immerges into.
A mechanism then presses the high-strength brake pads onto the fin
just like at a bike and the car slows down.
We are heading towards the brakes of the blue coaster before and
after the carousel in the main hall. "We call the coasters
the orange and the blue one to clearly distinguish between them",
Simone Fassbender explains the color labeling. In this
case the blue one is Winja's Fear. Every brake platform
can be easily reached even though they are up to twelve meters
high. Mostly there are broad staircases built for the access. This
is an advantage for the technicians, but also for the riders who
can easily leave the coaster in case of a breakdown - block brakes
are always used as predefined evacuation spots.
Every brake section has at least two independent mechanisms, and
each one is operated by an own drive using air pressure. Next to
the check brakes - which always exist twofold for redundancy
reasons - there sometimes are trim brakes (or scarf brakes), too.
The safety brakes used for the block clearance can bring the cars
to a stand and keep them in position while the trim brakes fulfill
the task of speed control. "The optical difference in the two
brake types is most obviously the pattern of the coating",
Simone Fassbender tells us. "So it's quite easy to
distinguish between them." There are also technical
differences that make the security brakes more fail-proof, but the
underlying principle is the very same.
the next block
The matutinal inspection mainly consists of the visual check of
the friction pad. The thickness is determined and the position of
the brake checked with a gage.
The 20 centimeters long pads are replaced as soon as they don't
comply with the specification for safe operation anymore. The
operativeness of the security brakes is a very relevant criteria.
The consequences would be fatal if the cars couldn't be stopped
because of a too strong wearout of the pads. To prevent this is
the duty of every operator of a roller coaster as well as of the
design engineer: One possible solution is redundancy, achieved by
the twofold installation of the safety brakes in every section.
Another way is fail-safe engineering: In case of a failure the
system automatically turns into a safe state. Applied to the
brakes this means that the cars come to a complete stop, even if
for example the power supply is cut off or the air pressure falls.
This is achieved by a simple mechanical component: a spring that
is integrated into the adjusting mechanism of the brake. In this
so-called spring brake cylinder the compressed spring stores the
actual work energy and provides that the brake is closed. The air
pressure then opens the brake against the force of the spring. So
during the regular operation the control unit has to explicitly
give the command to open the brakes, otherwise they remain closed.
A visual control of the mechanical components finishes the check
of every brake module. This includes the secure fixing of the
proximity switches. Those small turquoise boxes give a signal as
soon as a metallic object gets close. They are the sense organs of
the control unit and are versatility used: In every brake section
they can be found in many spots. They determine the state of the
brakes (whether they are open or closed) as well as the position
of the car on the track segment. Those data are processed and
provoke a reaction within milliseconds: So for example if the
speed of a car is determined, the closure time of the trim brake
can be calculated. This aims a controlled deceleration to a
specified speed. This speed adjustment isn't done in every brake,
but it still provides that a fast car can't get too close to a
slower one, which would cause the system to completely stop the
quicker one for a short time in the next safety brake.