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The
only modern water operated funicular
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Cables
and Security
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The
big drum.
Each car is pulled by its own cable. The two cars are linked
by a third cable for the tension. On the photo you can see
how the cable of the right car is winded to the drum. On
the left you can see the end of the cable fixed on the cylinder
of the drum. The cable of the left car is also winded to
the left part of the drum but upside down. The end on the
left cable is fixed on the hub flange. |
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The
bottom end of the tracks.
Here you can see the third cable which links the two cars
for the tension. Between the tracks a screw is used to tight
the cable but in fact this cable is not really tighted!
The third cable is an old haulage cable.
Near the pulleys, the two hydraulic jacks which are used
to empty the water tank of the cars. |
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Click
to enlarge
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Inside
of the top station.
On the photo you can see the ends of the rails of
the two parallel tracks, between the rails the nozzles
of the pipes which bring the water to the cars, in
the background the black drum |
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The
fourth cable.
The
thin cable under the main haulage cables, which winds
round 5 small pulleys at the top is the final emergency
breaking system. It works as follows:
- Any sharp jolt on this cable causes the emergency brakes
under the carriage to apply. These are cam shaped grippers
which dig in to the timber baulk
under the steel channel supporting the cable rollers in
the centre of the track.
This jolt may be caused by:
1)
Failure of the main haulage cable. Very unlikely as the
main cables are renewed every two years.
2) Major overspeed. Should the other breaking systems
fail and speed increase to twice the design speed of 0.6m
per second, the centrifugal governor on the yellow pulleys
activates jaws which clamp on to the small cable. This
pulls out the torpedo release and the carriage brakes,
softened by hydraulic dampers, bring the carriage to a
stop in a very short distance.
3)
Minor overspeed. Should the main speed control brakes
fail and speed increase to 1.8 times the design speed,
the centrifugal governor on the yellow pulleys flies out
and breaks the electrical supply. This results in all
brakes on the drum being applied.
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The
carriage brakes which are released by the security cable.
They are composed of four jaws which squeeze a wooden beam
between the rails.
In the foreground, the hydraulic jack which
controls the filling of the water tank of the car. |
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Not
so simple!
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Actuator (on the left), oil tank (on the top) and you
can see part of one of the four accumulators which compress
the nitrogen (bottom right corner). |
Once
the gate and doors of the carriages are closed the cumulative
weights are read by a computer in the top station, using
the pull of the cable on the winding drum.
Hidden underneath the front of each carriage is a tank which
can contain 1.6 m3 of water. The correct amount of water
is allowed through the pipe from the lake into the tank
of the top carriage. Then the brake is released and the
heavier car begins to move. The speed is measured by the
processor counting the gear teeth going by in the gearbox.
The processor then tells the electric actuator connected
to the control arm of the variable pump what to do. If it
is going too fast, the hydraulic pump pumps more oil into
the accumulator. Should the carriage being moving too slowly,
less is pumped. The pump controls this at the breakness
speed of 0.7 m/s!
Should there be considerably more passengers going down,
such as during the second half of the day, only a small
amount of water is used and the pumping is automatically
increased.
The accumulator accumulates energy by letting the oil compress
nitogen gas inside a bag. It is often used to drive the
hydraulic rams on the 'fills', 'emptys' and brakes etc.
When the gas is fully compressed, it is released to drive
a hydraulically powered water pump that fetches water from
the holding pond beneath the bottom station back up to the
lake. This elegant method ensures a little as possible of
the energy of the system is wasted! The holding pond also
obtains water independently from a stream underneath the
hill. |
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