Protective switch
A safety switch is a railway switch that leads to a dead end and is used to keep moving railway vehicles away from a route to be protected so that flanking is prevented. It is consciously accepted that the vehicles guided into the end of the track can derail or collide with the buffer stop at the end of the track. Safety points are used in places where protection from track blocks is insufficient.
technology
To avoid accidents in rail traffic, it must be ensured that the routes of rail vehicles are separated from each other. This protection is particularly necessary if major damage is to be expected in the event of an incident. It must also be effective in the event of human or technical failure. As a rule, track tracks are protected by shunting systems by technical measures that are effective in a purely mechanical way, because in most cases no automatic braking can be triggered by the train control on the vehicles threatening a route .
Track closures are suitable for keeping light vehicles that only move at low speed, such as unrolled single wagons, away from driveways. Their protective function is that they derail a vehicle rolling against the route to be protected and that it comes to a standstill due to the significantly increased rolling resistance in the gravel bed . They are ineffective if, due to their dimensions or their speed, the vehicles can reach the route to be protected even when they are derailed, because their direction of movement has not changed due to the track block. Rail closures and sand switches may therefore only be used in shunting tracks in Germany .
Protective switches are used to keep larger groups of wagons or trains away from the route. These guide the route of an undesired movement away from the route to be protected and thereby ensure that even derailed vehicles cannot reach the route to be protected. There must be enough free space behind the safety switch to rule out subsequent dangers from vehicles that have derailed or collide with the bumper.
In Germany, as part of the third regulation amending the railway building and operating regulations (pursuant to Section 14 (11 ) EBO), flank protection with safety switches is only required for tracks in train stations and junctions that are driven at more than 160 km / h.
execution
Protection switch with dead end
A switch is built into the track leading to the enemy route, the deflecting line of which leads into an approximately ten-meter-long stump track , at the end of which is a buffer stop. This protection track is arranged parallel to the travel path to be protected so that derailed vehicle can not endanger it. The buffer stop is used to prevent light vehicles that only move towards the end of the track at low speed from derailing. The safety switch is not used for operational purposes in this arrangement, but is usually a standard version, the distracting line of which can be driven on at 40 km / h. In arrangements in which it can be assumed that the protective function of the switch is only rarely used, the buffer stop can also be dispensed with.
Derailment switch
The derailment switch or derailment switch is a switch, the rails of which end directly after the tongues or after the frog , thereby derailing vehicles before they reach the danger point. In contrast to a track barrier, the vehicle is slightly distracted from the route to be protected in the event of a derailment, but is not completely diverted away from the route as is the case with a safety switch. So that the vehicle does not lean against the track to be protected when derailing, the track facing away from the track to be protected ends a threshold earlier than the track facing the track. The design is usually designed in such a way that the derailing vehicles cannot damage the turnout sleepers, thus avoiding expensive repair work. This type of protective switch is mainly used in Great Britain and is used there primarily when two main tracks are joined.
Zwieschutzweiche
A special form of protection switch is the intermediate protection switch . It has the task of protecting two routes, but cannot take over this function for both routes at the same time.
Operational safety switch
Operational switches can take on the function of a safety switch.
In the case of industrial tracks that flow into mainline tracks, points from stabling tracks or pull-out tracks can take on the function of a safety point. In such cases, the switches are integrated into the signal box of the station, even if the other switches in the marshalling system are operated manually on site.
At junction stations on single-lane routes, most traffic regulations require safety switches on the exit side if the trains are to enter the station from both directions at the same time. This prevents a train that does not come to a standstill in time from running into the flank of the opposite train. The function of the guard rail is usually taken over by industrial connecting rails , ramp rails or other side rails . In order to ensure safe operation in winter, the points that serve as safety points for side tracks must be provided with point heating .
Border lock
At the inner-German border , protective switches were installed on the GDR side to prevent unauthorized border crossing. The points were in a distracting position and were only switched to passage after the control had ended and the border guard had given their approval. This approval was built into the interlocking mechanism as a blocking circle in such a way that the switch could not be moved from the protective position without it.
Web links
Individual evidence
- ^ Walter Mittmann, Fritz Pätzold, Dieter Reuter, Hermann Richter, Klaus-Dieter Wittenberg: The Third Ordinance to Change the Railway Construction and Operating Regulations (EBO) . In: The Federal Railroad . No. 7-8 , 1991, ISSN 0007-5876 , pp. 759-770 .