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NordVPN.com/ArtofEngineering to get 75% off a 3-year plan. Link below. The Twilight Zone Tower of Terror at Disney’s
Hollywood Studios is often regarded as the best thrill ride to ever come out of Disney
Imagineering. The attraction seamlessly combines a 13-storey
drop tower with immersive dark ride elements, all tied together with detailed storytelling. The ride was considered to be an engineering
marvel when it opened in the summer of 1994, and although it may not have some of the advanced
technologies that are common on rides built more recently, it is still an impressive achievement
even by today’s standards. The Tower of Terror was such a success for
Disney that it was replicated on three separate occasions, at California Adventure in 2004,
Tokyo DisneySea in 2006, and Walt Disney Studios Park in Paris in 2007. The Tokyo version utilized a different theme
and storyline compared to the other 3 towers, and I personally find it to be the most aesthetically
pleasing of the 4 attractions. In 2017, the California version was re-themed
to the Guardians of the Galaxy film series, which included the addition of animatronics
and large screens for the show scenes, however the overall mechanics of the ride remained
unchanged. The first Tower of Terror in Orlando and the
most recent installation at Disneyland Paris both maintain the Twilight Zone theme which
is based on the classic tv series that aired from 1958 to 1964. The four Tower of Terror attractions are all
similar in concept, however the original Hollywood Studios version features a unique ride system
that is far more complex than the others, and it offers an experience that can’t be
found anywhere else. The tower portion of the ride building is
60.7 m in height, and it houses two 48 m tall elevator shafts where the drop sequences take
place, along with a large mechanical room above the shafts for the elevator motors. The rear portion of the building is about
half of the overall height at 32.0 m tall, and it contains the dark ride component of
the attraction along with the queue, load and unload areas, maintenance and control
rooms, and the gift shop. There are 4 elevator shafts located at the
back of the ride, and these connect to the main drop shafts through horizontal passageways
at the 1st and 5th show floors. After guests go through the hotel lobby, library
pre-show, and boiler room scene, they then board one of the 4 rear elevators at the second
floor. At this point, it appears that the elevator
car is the ride vehicle itself, but guests are actually boarding a semi-autonomous vehicle
that is positioned inside the elevator car. The ride vehicles are loaded onto the elevators
on the 1st floor below the passenger loading area, and they are held in place by a locking
mechanism on the floor of the elevator car so they don’t shift as the elevator moves. Once the passengers have boarded, the ride
starts by lifting the elevator to the first show scene. For the two inner shafts, the show scene is
located on the 3rd floor, and for the two outer shafts, the scene is located on the
4th floor. All four show scenes are identical, but they
are offset like this to conserve floor space. When the elevator doors open, the passengers
see a long corridor where 5 hotel guests seemingly appear out of thin air. The figures then disappear in a burst of electricity
as the hallway goes dark to reveal a single window in a field of stars. This scene is accomplished with two primary
techniques that Disney uses quite often: forced perspective and an optical illusion known
as Pepper’s ghost. The opening of the corridor is life-size,
but the walls, floor, and ceiling all slope inwards so that the height at the very end
is only about 1.2 m. This makes it appear much longer than it really
is when viewed from the inside. The wall at the end of the corridor is a rear-projection
screen with a projector placed on the opposite side. At the beginning of the scene, a normal wall
with a window is projected onto the screen, but the wall fades out of the image as the
lights go out to give the illusion of a window floating in space. At the front of the corridor just behind the
first arch, there is a large pane of glass oriented at a 45-degree angle that spans the
entire width and height of the hallway. This aligns with a second perpendicular hallway
where another rear-projection screen is hidden out of view. The 5 hotel guests are projected onto this
screen, and the image is reflected in the pane of glass making them appear in the middle
of the corridor. This illusion is known as Pepper’s ghost,
and it is the same effect that was famously used for the ballroom scene in the Haunted
Mansion. After the ghostly figures disappear, the projection
screen slides out of the hallway to reveal fiber optic cables that are used to create
the star field. Many of the walls in the corridor are scrims
made out of fabric, and fiber optic cables are actually hidden all over the show scene
behind the walls, as well as inside the elevator car. When the set goes dark, the light from the
cables shines through the scrims, and the cables in the perpendicular hallway are reflected
in the glass to make the star field appear three-dimensional. After the corridor scene is complete, the
elevator is then lifted to the 5th floor where the ride vehicle exits into the 5th dimension
show scene. This scene features a number of visual effects,
including a second star field that is achieved by two large mirrors with fiber optic cables
hidden behind them. The mirrors are oriented at an angle to each
other in a v-shape, and as the ride vehicle approaches, they slide apart to allow it to
pass through. Although there are 4 loading elevators and
4 corridor show scenes in the ride building, there are only two 5th dimension scenes on
the 5th floor. The four loading elevators are arranged in
pairs, and each pair connects to one of the main drop shafts through a single show scene. The horizontal motion for this part of the
ride uses a trackless system where the semi-autonomous ride vehicles navigate across the 5th floor
from one elevator shaft to the other. The vehicles are known as wire-guided AGV’s,
or automated guided vehicles, and they are equipped with sensors that ride close to the
floor surface. There are wires installed in the floor that
are used to transmit radio signals to the vehicle, and the vehicle is programmed to
follow the wires in a similar fashion to a line-following robot. The signals can also be used to control the
speed, direction, and orientation of the ride vehicle as it travels along the pre-determined
path. If the ride loses power and the radio signals
are cut off, or if something falls onto the floor and covers a wire, then the vehicle
will come to a stop automatically. The wire guidance system can be quite sensitive,
and it is one of the primary causes of downtime for the ride. Once the ride vehicle exits the 5th dimension
scene, it then boards an elevator car in the drop shaft for the main drop sequence. The elevator cars here are similar to the
ones used in the 4 loading shafts, and they also have a locking mechanism to secure the
ride vehicles in place. The ride has 4 pre-programmed drop sequences
that it can execute, and the computer selects one at random for each ride. Each sequence consists of a number of varying
drops and launches up the tower, with one full drop from a height of 39.6 m, or about
13 storeys. At the top of the ride, elevator doors on
the front of the tower are opened, giving guests a birds-eye view of Hollywood Studios. The two drop shafts actually extend about
8 m above this point inside the tower, but the top portion is not utilized during the
drop sequences. A certain distance is also required to safely
bring the elevator car and ride vehicle to a stop at the bottom of the tower, and so
the maximum drop height that passengers experience before braking is only about 27.4 m. The ride system that is used for the drop
sequences is based on the traditional traction elevator, and it is not that different from
an elevator that you might find in a normal high-rise building. The system was designed by the Otis Elevator
Company, and it uses two giant induction motors to accelerate riders up and down, reaching
a maximum speed of about 63 km/h. One motor is positioned above each elevator
shaft in a mechanical room at the top of the tower, and each one weighs nearly 60 metric
tonnes and can generate 2,000 HP. Each motor is connected to two cable drums
in series, and there is 1 solenoid brake on the end of each drum for a total of 4 brakes
per elevator. Two steel cables are wound onto the first
drum, and these extend down through the floor where they connect to the top of the elevator
car, which travels along rails that are fixed to the walls of the shaft. A single cable is more than strong enough
to support the full weight of a car along with a fully loaded vehicle, but two cables
are used for redundancy. Two additional steel cables are wound onto
the second drum in the opposite direction, and they are attached to a counterweight that
is used to offset the weight of the elevator car. The counterweight travels along its own set
of rails inside the shaft, and it weighs about as much as a single elevator car with an empty
ride vehicle so that the motor only needs to supply enough power to raise and lower
the weight of the passengers. Two more cables extend off the bottom of the
counterweight, and they run around a compensation pulley at the bottom of the shaft before connecting
to the bottom of the elevator car. This closed loop allows the motor to pull
the elevator car downwards, resulting in acceleration that is faster than a freefall. When the motor spins in one direction, the
car is pulled up from above, and when it spins in the opposite direction, the car is pulled
down from below. The result is an intense experience unlike
any other elevator where riders experience complete weightlessness one moment and are
pushed into their seats the next. But just like any regular elevator, the Tower
of Terror features a number of redundant safety systems that keep guests safe. First, there are the 4 solenoid brakes on
the cable drums that are used to control the speed of the elevator. Each brake has 2 arms with friction pads that
are clamped against the drum by a pre-loaded spring. There is a solenoid at the top of the brake,
and when electricity flows through it, the resulting electromagnetic force pushes a plunger
outward which separates the pads from the drum. When the flow of electricity is cut off, the
electromagnetic force is stopped, and the spring pushes the pads back against the drum. The friction between the drum and the pads
slows the drum down and brings the elevator car to a stop. This design is fail-safe because the brakes
are always active in their default state when the solenoid is powered off, and they will
stop the ride automatically in the event of a power failure. If the brakes were to fail, then a mechanical
speed governing system on the elevator car would activate emergency friction brakes that
clamp onto the elevator guide rails. There is a similar speed governing system
on the counterweight as well, so both the counterweight and the elevator car can be
brought to a stop by the emergency brakes. In the unlikely event that both steel cables
supporting the elevator car were to snap, this would also activate a set of emergency
brakes to prevent the car from falling down the shaft. If all of these safety mechanisms were to
fail simultaneously, which is extraordinarily unlikely, then the falling elevator car would
create a cushion of compressed air in the bottom of the shaft which would help to slow
the fall. There are shock absorbers installed at the
bottom of each shaft that would help to break the fall as well, however these are not designed
to catch an elevator car in a freefall. Fortunately, this has never occurred on any
of the Tower of Terror attractions, thanks to an over-engineered design and redundant
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back into Tower of Terror. After the ride has completed its drop sequence
in the drop shaft, the elevator then moves to the first floor where the ride vehicle
reverses out of the elevator. The vehicle moves backwards to the unloading
area, and it rotates 90 degrees for the guests to exit onto the unloading platform. While the vehicle is in this position, an
inductive charging system in the floor is used to charge the onboard battery in the
same way that you might charge a cell phone on a wireless charging pad. This is the only time during the entire ride
cycle when the vehicle is stationary on the ground, and so its also the only time when
the battery can be charged. The battery provides the vehicle with just
enough power for its self-driving and communication functions, and this is one of the reasons
why there is no audio or lighting onboard any of the ride vehicles. Instead, all of the ride’s audio and lighting
systems are located within the show scenes and inside the elevator cars. Once all of the guests have unloaded, the
ride vehicle then moves to the rear of the building where it boards one of the 2 loading
elevators on its half of the ride, and it is lifted up to the loading platform for the
next group of passengers. Since there are 2 loading elevators paired
with each drop shaft, each half of the ride can accommodate 4 ride vehicles operating
at any given time: 1 at the loading platform, 1 in the show scenes, 1 in the drop shaft,
and 1 at the unloading platform. This means that a total of 8 vehicles can
be cycling through the attraction at once, giving a total ride capacity of nearly 2,000
guests per hour. And since the two halves of the ride are independent
from each other, one side can often operate by itself when attendance is low or when the
other side is down for maintenance. This ride system makes the Tower of Terror
very efficient, however Disney decided to make changes to the design for the California,
Tokyo, and Paris versions to increase the capacity further and reduce downtime. Since the wire-guided AGV’s were a common
source of reliability issues, they eliminated the need for self-driving vehicles by removing
the 5th dimension scene and the 4 loading elevators. The corridor scenes that were previously attached
to the loading elevators were moved over to the drop shafts, and a second show scene was
added at the 5th floor. The scenes vary quite a bit between attractions,
especially with the recent conversion of the California tower to Mission: Breakout, however
they all originally featured similar effects like forced perspective and Pepper’s ghost,
as well as other mirror tricks. Since the new ride layout does not utilize
AGV’s, the loading platforms had to be relocated to the drop shafts, but here the ride vehicles
are loaded and unloaded outside of the elevators. Once passengers have boarded a vehicle, it
is pushed into the elevator car by a mechanical grab that travels along a track, and after
the ride is finished, the grab pulls the vehicle back out of the elevator for unloading. A second loading area was also added one level
below the first, which allows one vehicle to be loaded while a second one is going through
the ride cycle. The elevator system itself is essentially
identical to the original one used in Orlando, but here it is used for the main drop sequence
as well as moving between the show scenes. Since each drop shaft can only accommodate
2 ride vehicles in this configuration, a third shaft was added so that a total of 6 vehicles
can cycle through the attraction at a time. This greatly increased the overall capacity
of the ride, and it also allows two shafts to remain open when one is down for maintenance. There’s no arguing that the second iteration
of Disney’s Tower of Terror is a far more optimized design compared to the original
Hollywood Studios version, however it doesn’t quite offer the same immersive experience
that you can only find in Orlando. While Tokyo may have the best aesthetics,
and California may have the most engaging storyline, there’s still something special
about the journey through the Hollywood Tower Hotel and crossing over into the 5th dimension
that Imagineers simply haven’t been able to reproduce. Hey everyone, I hope you enjoyed today’s
video about Disney’s Tower of Terror. Let me know what your favourite Disney attraction
is in the comments, and I’ll try to make a future video about the engineering behind
it. Please subscribe if you want to see more content
from this channel, and don’t forget to hit the bell to get notified as soon as new video
comes out. Thanks for watching, and I’ll see you in
the next one.
My daughter is still mad at me for convincing her to go on this. She hates drop rides and dark rides, double nope for her. I thought it was great, seeing the engineering behind it was impressive.
I rode this in 1996 and it was amazing to me at the time.
I love this YouTube channel. His content is well done and fun to watch.
I still have some form of PTSD from going on this ride when I was 13. I'm 32 now, heading to Disneyland in a month and this is the only ride that terrifies me and churns my anxiety.
I miss the Twilight zone theme at California Adventure. I think it was better than the Guardians.
Just rode this last week.... I loved it!
I appreciate the conversion from horse power to duck power at 8:27 really helps me mentally picture the amount of ducks it would take to operate the ride.
I just recently watched this also. It was way more going on than I thought.
Fuck this ride and everything about it - Seven year old me