Hook claw
A hook claw is a U-shaped double hook made of metal that is attached to the catenary of a railway line for sabotage purposes and then locks like a carabiner . If an electric locomotive drives through, its pantograph gets caught in the claw and, depending on the speed of travel, pulls the overhead line with it for several hundred meters.
In Germany, the contact wire voltage is 15,000 volts , so there is a risk of fatal electric shocks both when attaching the hooked claw and when the overhead line is torn down .
construction
There are several, slightly different designs. A common design of a U-shaped hook claw consists in the main body of structural steel, as it is used for strong reinforcing steel in reinforced concrete construction, and is approx. 15 cm long. A simple swivel joint D is welded to one side of the main body, which is bent twice by means of forging and heating, and which receives a bolt C for a carabiner-like attachment. When hooked into a cable, the bolt folds up, after the cable is in the U-shaped part, the bolt folds down and thus prevents the hooked claw from being thrown upwards from the overhead line in the event of a sudden impact with the pantograph. The bolt is held in its position by two pins B1 and B2 , which are also welded to the main body and can therefore rotate a maximum of approx. 90 °.
Since the catenary is under high voltage, several meters above the ground and the two hooks in the U-shaped double hook are only a few centimeters apart, there is an additional locking pin A welded on the side of the claw with a length of approx. 10 cm. The claw can be lifted up with a long, electrically insulated and stiff plastic pipe, like the one used for sewer pipes. A second insulating tube or insulating rod is required for removal in order to first push the locking pin C that has snapped shut over the cable upwards. The hooked claw can then be removed from the line upwards via the plastic tube on the locking pin A.
Contemporary history
Hook claws have become known as sabotage devices used by autonomous groups in attacks against Deutsche Bahn in connection with the transport of nuclear waste .
The hooked claw has caused quite a stir on the Internet , because building instructions for it were among the first websites on foreign servers that were blocked by German instigation.
Individual evidence
- ↑ Christiane Schulzki-Haddouti: Deutsche Bahn sued XS4ALL in 2002 because of the left-wing radical magazine "Radikal" and won. In: Heise online. Heise Zeitschriften Verlag, April 15, 2002, accessed on March 21, 2011 .