View around maintenance area

7:00 Now we are standing in the station - the tour is over, but the work is not. The ride has to be operational in two hours. Passing the control room we are heading through the exit towards the maintenance area: Directly behind the two vertical lifts there is the holding track within a well equipped garage - the realm of the mechanics. A moveable track segment connects the holding track with the ends of the track of the lifts. Venetian blinds separate the lift from the maintenance area. Once hey are lifted, a track segment of around one meter can be turned down to be able to shunt the cars. The control system automatically detects the number of cars employed, it can even identify each one with the aid of a numerical code. This code is permanently attached to the cars close to the chassis and can be read out contactlessly in the station. Beyond other facts the number of turns each car made can be determined - an important information to coordinate the service cycles.

Unused Car

In the far end of the room we see the two holding tracks. "Today we will use three cars per side", Karl Heinz Gehring calls from a corner of the room before he joins us again. The other cars remain in the garage and can be maintained during the day. In the middle of the room one car is jacked up without its fiberglass cladding, so the complex but compact mechanisms are clearly visible. Maurer Söhne filed a patent for this type of car in 1997 and it was granted four years later. The absolute novelty is the spinning mechanism of the cabin whose rotation around the centerline is dampened down by a centrifugal brake. This mechanism is quite simple: Two weigths are pushed to the outside according to the laws of centrifugal forces caused by the rotation of the cabin. A system of levers transfers this movement to a brake mechanism that is pre-stressed by a set of springs. At a defined point the prestressing is overcome and the brake engages. This prevents overstepping of a maximum rotational speed. Such a control is essential in such a chaotic spinning system because the forces on the passengers have to be kept within a predefined margin. This system is another kind of control, but this time it is totally self-sustaining and without the influence of the central electronic control system

Safety restraint mechanism

But the car can't move along the track without external power connectors or defined contact spots: Some of those are the contacts attached to the cars for interaction with the proximity switches or the code retrieval unit for the car identification, others the already mentioned levers for the fixation of the cabin. But most important is the monitoring device for the restraints and the system that opens them automatically in the station. Karl Heinz Gehring explains their functionality: The restraint is pivotingly attached to the frame of the car. At the frame two spring-loaded detents engage with two parallel sawtooth profiles. The detents skip from tooth to tooth while the restraint is pulled towards the passenger. But that is not all: Before even the first detent gets a grip, a bolt snaps in at the bottom side of the support point.

Friction wheel and eletrical power line at the station area

This triple safety is completely sufficient and is checked after a certain number of ride cycles of every car. The sawtooth profile is exchanged as soon as it's worn out too much. In general the locked state can only be suspended by a lever that is attached to the underside of the car. In the station this is done by a trigger which is operated by the control system. It can also be done by hand, for example when evacuating the vehicles. But the lever is implemented in a way that it can only be actuated by the personnel.

But the cars won't be dispatched without an additional control: The proper fit of the restraint is checked by the personnel in the station. In addition the closed state is determined by a switch that is read out by the PLC using sliding contacts within the station area. The restraint has to be recognized as closed by the system and the operator in the station has to confirm the proper fit of the restraint before the control unit allows the dispatch of the car. There is no possibility to circumvent this safety measure.

7:15 We now turn towards the two express lifts arranged side by side, one for each track. Those two elevators carry the cars to a height of 17 meters within just five seconds. At the same time the track is tilted by 30 degrees to enable the direct alignment with the first drop at the highest point. The cars are pushed from the station onto the lift track by friction wheels. Then they are secured similarly to the see-saw element and the retractable track.

Team leader Werner Kuhl controls the mechanisms of the vertical lift

Werner Kuhl controls the brakes here, too, inspects the pressure ports, checks the safe fixation of the limit switches and examines the mechanics that additionally prevent the cars from an unintentional and early descent from the tilted track. The strutted and open elevator cage like the guide rails for the vertical ascend are invisible to the passengers during the ride. Instead there is complete darkness. Mystic music and sound effects add to the atmosphere and increase the anticipation during the last seconds before the first drop.

A high-performance electric motor in the power house caters for the necessary tractive force. Turned round by a couple of pulleys the steel ropes go up and down the shaft. But a drum that coils the rope is looked for to no avail: The ends of the multiple parallel ropes are attached to the upper and lower part of the cage and form a closed loop. Weights keep the tensile strength, a basic requirement for the operation of the lift. Nothing at this drive is left to chance: The tilted lift track is held in position at the highest point by additional brakes that grip a support attached to the structure of the shaft. Without them the track segment would move too much after the front under-carriage has rolled past the crossover and the tilted section is suddenly unburdened.