Train protection system

Train control, train control or train control system called technical equipment and systems for railways that control the passage of trains depending on the permitted speed. If the drive is not authorized or is a train too fast, he is stopped automatically by a train control system.

To secure the movement of trains various technical systems and operating rules were developed in the 19th century. Widely used are signals that rides for a certain section let ( stationary) or prohibit (stop position ), the simultaneous Allow enemy trips is often largely excluded by technical dependencies. However, signals do not act directly on the train. The driver must perceive them, and brake in accordance with the train when approaching a stop pointing or the rate -limiting signal. But Overlooks a train driver a signal, it can lead to serious hazards and serious accidents. To counter this threat, systems have been developed that intervene directly in the vehicle operation, if necessary by trigger an emergency brake. Using the same technique can also be the speed of the trains monitor.

  • 3.1 Line cable 3.1.1 rail line cable
  • 3.1.2 cable line cable

Legal situation

In Germany must Railroads, the primary paths or secondary paths on which drive faster than 80 km / h down or several trains and passenger trains takes place or drive faster than 50 km / h, driven with an automatic train control system equipped (§ 15 EBO ). The trains running on these routes, locomotives, multiple units and driving trailers need a vehicle of the relevant train control equipment. (§ 28 EBO )

Routes where no more than 160 km / h are permitted, have to be equipped with an automatic train control, holding a train automatically and an illegal approach to stop pointing signals monitored ( § 15 Section 2 Sentence 1 EBO ). The specific design of this requirement is for the railway infrastructure company. On lines of DB Netz this is mainly the inductive train control of three-frequency resonance type (formerly inductive magnet ) are used, the evaluation is performed by a vehicle apparatus of the type PZB 90 The use of an automatic train ( LZB ) but is also possible and is then used to block compression applied as indicated on the route Karlsruhe -Basel or the S-Bahn Munich. Also ETCS Level 1 meets the requirements of the EBO, however, is so far apart in Germany of test tracks still not been admitted.

Routes on which more than 160 km / h approved must be equipped with an automatic train control system, brought by a train automatically to hold and can be performed as well. For this purpose, the so-called automatic train and in the future ETCS Level 2 is used in Germany. ETCS Level 2 was still registered in Germany in any way.

In other countries, it is considered that:

  • Are required for speeds above 160 km / h linear train control or at least Zugbeeinflussungen with semi-continuous data transmission.
  • At speeds above 160 km / in addition the Automatic drive and brake control h should be used.
  • Are necessary for metros and light rail vehicles because of the high train density and the tunnel even at low speeds train controlling system.

Punctual Zugbeeinflussungen

Punctual Zugbeeinflussungen transmit the signal information only at discrete points - often at the sites of the track signals -. Onto the train They are not fail- safe because they act according to the work flow principle. Failures of route setup are detectable only by special tests. Nevertheless provide punctate Zugbeeinflussungen a high security growth at relatively low cost.

By type of information transfer are or were there the following types of punctual automatic train:

Mechanical Train Control

The information is transmitted on or before the stop signal by mechanical contact between track and vehicle equipment. The mechanical automatic train control system is suitable for relatively low speeds up to 90 km / hr. Known Application: ignition interlocks, eg at the Berlin S -Bahn.

Electromechanical train control

The power transmission from a moving train on the route setup is done with brushes or contact shoes. The current return via the rails. Through snow and ice disturbance in the signal transmission may occur. Known Application: Crocodile by the French, Belgian and Luxembourg railways.

Magnetic train control

In the magnetic train control are located on the route permanent magnets whose magnetic fields are recorded and evaluated from passing locomotives. An arranged adjacent to the permanent magnet solenoid builds when driving signal showing an opposite magnetic field, so that the effect of the two magnetic picks up and the trains can pass through unhindered. The magnetic train control is also referred to as a magnetic moving blockade. Applications are limited to rail systems with consistently moderate speeds:

  • Train control of the Hamburg elevated railway,
  • ZST -90 and ZSI -90 some Swiss narrow gauge railways
  • Various mining railways and industrial railways

Inductive Train Control

Inductive Train Control System uses data transfer by electromagnetic coupling.

Inductive Train Control System with magnetic DC field

The permanent magnet or electromagnet of the passing vehicle engine induced when passing over a track magnet a current is short-circuited signal showing when driving. When driving signal showing a second electromagnet induces a current in the receiver coil of the vehicle, which is evaluated by the onboard system. This train control can take only two states and transmitted. Known Application: Integra - Signum in Switzerland

Inductive Train Control System with alternating electromagnetic fields in the low frequency range

A vehicle -supplied with alternating current generates an alternating magnetic field which induces a voltage when passing over a magnet in the track. The current in the vehicle tank circuit is weakened by feedback (resonance) of the track resonant circuit on the vehicle magnets, which is evaluated from the vehicle. This train control can take only two states and transmitted.

Known Application: Indusi / PZB in Germany, Austria and other countries

Inductive Train Control System with alternating electromagnetic fields in the radio frequency range

Track coupling coil ( beacons ) transmitted data messages bidirectionally between vehicle and track coupling coil. The necessary energy is radiated from blowing vehicle antennas and received by the track coupling coil. With the large volume of information transmitted, precise braking curves with target speed and target distance can be calculated. Because each track coil removal mitüberträgt the next data point, failures are detected by track coupling coil (supervised circuit principle ).

Known Application: automatic train control system S- Bahn Berlin

Optical train control ( Opsi )

When Opsi the routes were secured with light barriers. Because unreliable, the system worked for pollution, the experiments in Germany were set in 1943. Application: Type Bäseler Zeiss

Zugbeeinflussungen with continuous data transmission

In these systems, data between track and train are exchanged without disruption. This changes the approved speed immediately be transmitted to the vehicle, which improves the operational flow and increased safety. Continuous transmission systems operate according to the principle of power, making the route setup failures are detected on the vehicles immediately. They cause high costs, but are essential for high-speed traffic. Due to the fail- safe display the permitted speed in the cab of stationary signals are dispensable. With such systems, a largely automatic drive and brake control is possible.

Line manager

Line cables allow the inductive transmission of information to the vehicle.

Rail line cable

The signal is transmitted via an electromagnetic field that develops in track circuits to the rails around. About locomotive receiving antennas, the field is sampled and thus receive the fed into the so-called coded track circuits information. The disadvantage is that in contrast to the cable line cable larger electrical damping, whereby only a small amount of information can be transmitted. Different frequencies of coded track circuits allow the transmission of multiple speeds. One stop from top speed via several sections, the speed levels are chosen so that there are about the same braking distances to the next lower section.

The system is technically simple and requires in addition to the track circuits no additional conductors in the track. For the transmission of additional information that are received prior to the first axis of the leading vehicle, the track circuits, however, must be reversible. It is required that during a train journey, the relay side of the track circuit is always first traveled. When traveling against the permit and in stations without set driveway no continuous information transfer is possible. Since no location information is transferred from the train to the wayside equipment, the length of track circuits and hence the length of the block sections must be adjusted depending on the slope ratios of the length of the braking distance. Because the information " stop" is recognized only when driving on the block section, the danger point is behind the end of the section.

Known Applications: TVM on French high-speed lines, RS4 Codici and BACC in Italy

Cable line cable

For data transmission is an electromagnetic field that propagates to a continuous tape between the rails cable. At fixed intervals, such as every 100 m are crossed cables. These intersections may be used for determining the position of the trains. The system is characterized by good transmission characteristics between ground and vehicle and vice versa. Due to the possibility of extremely short block distances very small headways can be achieved. However, the cable line cables are susceptible to damage, eg in railway works.

Known Application: Linienzugbeeinflussung ( LZB ) in Germany and other countries

Radio transmission

The wireless technology has developed so far in the last few decades that it can be used for secure data transmission between fixed route centers ( Radio Block Center RBC) and trains. It has the advantage that no devices are required in or on the track. The prerequisite is a stable wireless connection, in case of interruption or failure, the trains can only move in control. For economic reasons, track internal radio services and the mobile phone supply travelers with the standard GSM -R are summarized.

Europe-wide application with ETCS Level 2 and 3

Zugbeeinflussungen with semi-continuous data transmission

A point train control system transmits the information only in certain places on the train, where they are evaluated to ensure the train ride. Between the transmission points ( ÜP1 and ÜP2 pictured right ) there is no information transfer. If shortly after passing the distant signal a rate- enhancing signal term is driven operation creates a disability. If the signal changes unexpectedly after passing the distant signal at danger, but this is very rare, creates a risk for. Such problems can be reduced by a subsequent at the transfer point ÜP1 continuous signal transmission. Such Zugbeeinflussungen with semi-continuous data transmission consist of components of point Zugbeeinflussungen and system with continuous data transmission.

The semi-continuously acting systems include ETCS Level 1 ( Europe ), SELCAB (Spain) and ZUB 121 ( Switzerland ).

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