Track closure
A track barrier , called a track barrier shoe in Austria and a derailment shoe in Switzerland , is a mechanical edge protection device in railway tracks . In the language of the railway workers it is also called "dog", "witch" or "rug".
function
A track lock prevents rail vehicles from driving on the track beyond the point secured with the track lock. Track closures should, as well as safety switches , in particular prevent accidents caused by flanking that z. B. can be caused by rolling parked, accidentally unsecured rail vehicles or by a shunting trip . In contrast to signals - which only work if they are observed - they count towards "immediate" or "mandatory" flank protection . Driving over an applied track barrier leads to the deliberate derailment of the rail vehicle in the opposite direction to the track to be protected. The metal blocking block (derailment shoe) of the track barrier can only be rolled over by lifting a wheel of the rail vehicle, which - at least at lower speeds - pushes the vehicle in the "ejection direction" to the side of the rail and thus derails it.
In Germany, track closures are used to secure sidings at a train station that lead into main tracks and, under certain conditions, also the tracks at junctions that branch off from the open route . In Germany and Austria, track closures are not permitted in main tracks, in Switzerland they are also used in main tracks in certain cases.
construction
In Germany, a track barrier consists of a derailment shoe that can be folded onto a rail and is supported on a support bracket when it is in place. Older track barriers require a sleeper compartment with wooden sleepers and special ribbed plates to be extended to a sleeper spacing of 75 centimeters . The newer design is narrower and can also be installed in threshold compartments with the usual 60 centimeters spacing. If operationally necessary, it is provided with a track lock signal, with track locks that are not dependent on switches and therefore could be driven over from the rear receive two track lock signals, one for one direction each. Locally operated track closures that are frequently changed are given a manual control device with hand weight. There is a welded handle on the derailment shoe for switching without this. In order to minimize damage in the event of derailment, a threshold for the wheels running inwards is installed on the side of the track opposite the derailment shoe when the track barriers are permanently installed. A crankshaft between the rear and the next one distributes the impacts from impacting axles over several sleepers and thus secures the position and function of the track barrier.
In order to create subsequent dependencies , a track barrier can be equipped with track lock locks for open and closed positions. Remote-controlled track barriers receive a drive corresponding to the interlocking design, in principle a point drive. Mechanical track barrier drives also have a coupling lever that holds the track barrier in the end positions and also compensates for fluctuations in the travel. In the signal box, track barriers are treated like safety points with no track connected to one line. If the track lock is in place, the associated track lock signal shows the signal aspect Sh 0 as a form signal (a horizontal black stripe in a round white disc on a black background) and, if the position must also be recognizable from behind, two white lights next to each other. If the track barrier is removed, the signal shows the term Wn 7 (a vertical, black stripe in a round, white disk on a black background) and a white light on the back. The signal can be illuminated from the inside, otherwise the white surfaces are reflective. In the past, with the DR until 1960, in the network of the former DB until 2008, the signal aspect Gsp 1 or Sh 1 was used in its place. There is a transition period of twenty years for the conversion.
In Germany there are also derailment switches with similar functionality, the branch of which leads into the ballast without a track termination. The turnout signal of these turnouts corresponds to that of track closures.
In other countries, technically different designs are known. For example, in Portugal there are hinged steel elements erected with chains, in Hungary there are locking beams in the form of double T-beams that can be rotated across the track.
See also
Individual evidence
- ^ Deutsche Reichsbahn: Principles for the design of the safety systems on main lines and the branch lines that are used at more than 60 km / h . Edition 1959, as of October 1993. ( on the website of Ulrich Maschek at TU Dresden )
- ↑ Jörn Pachl: System technology of rail traffic: plan, control and secure rail operations . 8th edition. Springer Science + Business Media , 2016, ISBN 978-3-658-12986-6 , 4.2.4.2 Flank protection against enemy maneuvers and unintentional wagons , p. 108 ( limited preview in Google Book search).
- ↑ See e.g. B. the final report of the Accident Investigation Center for Railways and Ships on the train hazard in Burgdorf station between the freight train 62406 and the S-Bahn train 16418 (S44) on Tuesday, September 9, 2003
