Indusi

Indusi track magnet (bottom left) and vehicle magnet (right)

Uerdinger rail bus . To the right of the actual control desk is the retrofitted Indusi console.

Indusi is the name of the inductive train control system of the three-frequency resonance design used in the German railway network since 1934. It is a punctiform train control . Originally, it was as Indu ctive train si insurance referred. It is also used in this form in Austria , Romania , Israel and the successor states of Yugoslavia .

The modern, microprocessor-controlled variant of this train control system is called point train control or PZB .

history

German Reichsbahn

An early functional model , which clearly shows a mechanical effect triggered by a magnet on the steam supply lines of a locomotive .

Vehicle magnet prototype on the tender of a steam locomotive (1930)

Flying Hamburger express railcar . 1935, two years after the DR with the Flying Hamburger her emanating from Berlin rapid transit resumed, 18 speed rail cars and 147 locomotives were already equipped with Indusi.

In 1909, Siemens & Halske developed an electromechanical train control system for the first time, but it did not work reliably enough in snow and heavy pollution. Magnetic train control was introduced around 1926, although this required an energy supply for the line equipment. In addition, other technologies were initially pursued, including the optical train protection of the Bäseler-Zeiss type , the appearance of which, however, tended to become dirty.

The use of inductive train protection was proposed as early as 1919. After a series of preliminary stages, the United Railway Signal Works and C. Lorenz AG, together with the Deutsche Reichsbahn, developed the resonance design with three frequencies . The train control system , then called inductive train protection , which was tested on the Berlin – Hamburg and Hamburg – Bremen lines from 1927 , does not require a local power supply for the line facilities. As a rule, there was no power connection or free cable cores to the signals in mechanical interlockings . The first experimental units already had the basic structure with 500, 1000 and 2000 Hz resonators , which transmit the signal aspect via an induction coil to the traction vehicle before a signal , control its speed and trigger an emergency brake in the event of danger of driving past the signal without authorization .

The resonance design avoids the weakness of train influences in direct current design, such as. B. the Swiss system Integra-Signum , not triggered when driving at very low speed. At the same time, the resonance design is insensitive to iron masses in the track, for example in points . On the other hand, the generation of alternating currents with the three different frequencies requires equipment that was quite complicated in the technology of the time.

The first series design was the Indusi I 34 , in which the required alternating voltages with frequencies of 500, 1000 and 2000 Hz for steam locomotives were generated directly by the turbo generator equipped with additional windings , the speed of which had to be kept constant. The quiescent current in the vehicle magnet was around one ampere. In 1935, 165 locomotives and 4500 kilometers of route were already equipped with Indusi.

Due to the effects of the war, the Indusi devices installed by then had to be shut down on 870 vehicles and 6700 kilometers of route.

post war period

In 1947 a new beginning was made with 870 on-board devices and 1180 kilometers of route. The vehicle equipment was standardized in 1954 by what was then the Deutsche Bundesbahn (DB) as Indusi I 54 . In the system I 54 and its successor Indusi I 60 , the required AC voltages are no longer generated directly by a rotating generator , but by transistor generators. While Siemens used a single generator for each of the three frequencies, a single generator with downstream frequency dividers is used in the SEL design . The quiescent current in the vehicle magnet was reduced to around 200 milliamperes, so that the track magnets could also be made smaller and lighter. However, these track magnets could no longer be used with vehicle devices of the original type I 34.

The DB route network was quickly and systematically equipped with Indusi. In 1966, train protection devices were installed in 5,494 (67%) locomotives and control cars . In mid-1967, 13,356 km (73%) of the main line network with Indusi was secured. By 1975 90,000 track magnets had been installed. In 1980, the equipping of the DB network was essentially complete: all main lines and the branch lines serving passenger traffic (22,000 km in total) and 9200 vehicles (99.5%) are equipped with Indusi.

In the GDR , all Indusi line facilities and subsequently also the vehicle equipment were expanded after 1945. The re-use failed primarily due to the almost area-wide dismantling of the second track. Priority had to be given to changes to the safety systems for single-track operation. However, it was decided to store the removed material in a way that preserves its value. In the 1960s, a train control system began again, initially only with 1000 Hz control on advance signals. The stored track magnets were refurbished for this purpose, but especially those from the last years of construction, in which only the middle part with the coil windings had been potted, proved to be often no longer capable of being refurbished and damaged by corrosion. In the 1970s, Indusi equipment was imported from the Federal Republic of Germany, in addition to vehicle equipment in particular for locomotives that were used in the DR – DB alternating traffic, this also affected track magnets. As a result of accidents, the GDR developed its own vehicle equipment in three-frequency design from the end of the 1970s.

construction

Vehicle equipment

Basic circuit diagram Indusi
(shown for one frequency)

Vehicle equipment (red):
G Three-frequency generator
C ₁ capacitor
L ₁ vehicle
magnet (coil) R Pulse relay for

track equipment (blue):
L ₂ track magnet (coil)
C ₂ capacitor
S Short-circuit switch (closed when the signal is moving)

Vehicle magnet on a Traxx locomotive

The vehicle magnet is located on the right-hand side of the traction vehicle or control car, usually on the first bogie . Its three coils are permanently fed with alternating currents at frequencies of 500, 1000 and 2000 Hz from the vehicle equipment. In older systems there is a bistable relay in each circuit , the pulse relay , which triggers further switching processes. In modern systems, the current is monitored by electronic components that pass the changes on to the evaluation module. Any influences, actions of the driver, air pressure in the main air line , driving speeds and other data are recorded on a paper strip or in electronic storage devices. After accidents or other dangerous incidents, the registered data is saved and evaluated.

The vehicle equipment of the three-frequency design is basically constructed in the same way. However, there are differences in the generation of the required alternating currents, in the evaluation modules and in the registration devices.

Track equipment

The track magnets are located on the track, the coil of which, together with a capacitor, forms an oscillating circuit tuned to a specific frequency . They are attached to the rail on the right-hand side in the direction of travel and aligned with magnetic track holders.

The 1000 Hz magnet on pre-signals or monitoring signals from level crossings checks that the warning position of the signal has been picked up and that braking has been initiated.

The 500 Hz magnet is 150 to 250 meters in front of a main signal that covers a particular danger point. It checks the braking process for a specified speed and ensures that the protective distance behind the main signal is not crossed without permission.

The 2000 Hz magnet on the main signals serves as a travel lock when the signal indicates a stop and immediately triggers emergency braking.

1000/2000 Hz double track magnets are used on main signals with pre-signaling or if there is a pre-signal and a main signal at the same location. Their resonance frequency can be switched by a switchable capacitor . Practically all newer 1000 or 2000 Hz track magnets are double track magnets. If only the 1000 Hz function is required, then the additional capacitor is permanently connected to the resonant circuit with a bridge to be inserted. With pure 2000 Hz magnets, the additional capacitor is not connected.

Switching solenoids contain no capacitors, the coil does not form an oscillating circuit. They do not influence the vehicle equipment when driving on, but are used to control speed test equipment .

The track magnets are active in the basic position or not connected. In the case of form signals showing the way , the track oscillating circuit is short-circuited by contacts of wing or window current closers , in the case of light signals by relay contacts. The track oscillating circuit is thus detuned to such an extent that the on-board unit is not influenced.

1000 Hz track magnets are also used to secure slow speed areas (with a limitation of 80 km / h or less). At slow speeds with a speed below 40 km / h, the braking process is also monitored with a 500 Hz magnet. Speed limits between 90 and 140 km / h can only be secured with speed test devices.

Not all routes were or are fully equipped with 500, 1000 and 2000 Hz magnets. In the early days, only distant signals were provided with 1000 Hz magnets.

function

The vehicle magnet permanently generates an electromagnetic field with a frequency of 500, 1000 and 2000 Hz. When driving over a track magnet, a voltage is induced in it . In the case of resonance - when the frequency of the vehicle magnet corresponds to that of the track oscillating circuit - the current in the vehicle oscillating circuit of the relevant frequency drops sharply, the pulse relay in its circuit, which is in the basic position, drops out and triggers further switching processes.

Operating program

Indusi track magnet

When passing a pre-signal or main signal with pre-signaling, which is expected to stop or announces an expected speed below 90 km / h, the vehicle equipment is influenced by 1000 Hz. The driver must press the alert button within four seconds. In this way, he confirms that he has recognized the speed-limiting signal aspect and is initiating braking. Without this acknowledgment, a warning tone sounds and an emergency brake is applied. At the same time, the braking process to be initiated is checked by a time-dependent speed monitor. The test speed depends on the braking position and the braking ratio ( braking hundredths ).

A 1000 Hz influence also occurs on level crossing monitoring signals if the level crossing safety system is not switched on or is disturbed.

The 500 Hz track magnet triggers an additional speed test if the following main signal shows stop or a speed below 40 km / h. Here, too, the test speed, beyond which an emergency brake is triggered, depends on the braking position and the braked weight.

Monitoring points of the Indusi I 60:

Indusi- train type	Braking position	Braking hundredths	Test speed 1000 Hz influence	Test speed 500 Hz influence
O	R / P	over 110	95 km / h after 20 s	65 km / h
M.	R / P	66 to 110	75 km / h after 26 s	50 km / h
U	R / P	under 66	65 km / h after 34 s	40 km / h
U	G	all values	65 km / h after 34 s	40 km / h

One consequence of equipping slow speed zones of up to 80 km / h with uncontrolled 1000 Hz magnets is that trains in train types M and U sometimes have to be slowed down significantly further than is actually necessary for the slow speed zone.

The 2000 Hz track magnet on the main signal immediately triggers an emergency brake when the signal indicates a stop. In this way, trains that still pass the signal despite the two previous tests are brought to a standstill within the slip path .

If it is necessary to drive past a main signal indicating a stop despite an active 2000 Hz track magnet, the influence can be bypassed by pressing the command key . Such a trip can be initiated by a substitute , cautionary or counter-track substitute signal or by a written order issued by the dispatcher . The triggering of the emergency braking is thus suppressed, but the influencing and operation of the command key are recorded on the recording strip. During this time, the maximum speed is limited to 40 km / h and a permanent acoustic warning sounds.

Another application of the Indusi is the monitoring of the permitted speed in front of a danger point on the route by means of a speed test section .

Indusi outside the Federal Republic of Germany

Outside Germany, the Indusi is also used in Austria, Romania and at OC Transpo in Canada. In Turkey some routes are also equipped with the system. The German Indusi was also used on the Yugoslav Railways. It was retained by the successor railways after its disintegration.

Israel is a special case . There is practically an identical system supplied by German manufacturers, but the magnets are adapted for left-hand traffic on the left-hand side in the direction of travel.

Indusi I 60 was installed as a fall-back level at the Mecca Metro in Saudi Arabia .

German Democratic Republic

Hl signal with track magnet in Golm station near Potsdam.

At the Deutsche Reichsbahn (DR), vehicle equipment and, a little later, track equipment from reconditioned old stocks were installed at the end of the 1960s. At the same time, locomotives were equipped with I-60 systems from Siemens and later with Romanian I 60 Icret replicas . The control at light signals takes place from the outset track magnet control relay (at the beginning I for Indusirelais later PAG, p unktförmige train control, A nschaltrelais, G slightest magnet) in a relay box on the signal mast. In the case of signals with direct current feed in particular, low-resistance current relays have been switched into the lamp circuits. In newer interlockings, voltage relays are used which are controlled by the associated signal group via additional cable cores. In the early days, the PAG relays in the main red circuit were monitored. A stuck PAG relay would have made itself felt by a replacement red connection. Due to the no-load switching of the PAG relays, this case never occurred. For this reason, this monitoring was waived again from 1986. In the case of block signals from the automatic section block, if the cable path between the block cabinet and the signal is short enough, direct control from the block cabinet without a relay box on the signal mast is possible and common.

To replace imports and because of the necessary modernization, the VEB equipment and control plant Teltow developed its own punctual train control system with the designation PZ 80 and also its own track magnets and track magnet holders, which is compatible with the existing line equipment . The vehicle equipment generated the required AC voltages like the Siemens type devices with three individual transistor generators.

The PZ 80 supported extended functions in addition to the original Indusi. A maneuvering program made it possible to drive past signals indicating stop. This maneuvering program also monitors the speed at 40 km / h. Switching between the speed limit program and the maneuvering program was easy with two separate buttons. The maximum speed of the trains was specified not only in three train types, but in 10 km / h steps between 50 and 160 km / h. The maximum speed above 6 km / h was secured by emergency braking, which - as with the I 60R - did not work to a standstill. The monitoring of the braking process after a 1000 Hz influence did not take place punctually through the attached speed test after a period of time, but through a continuous braking curve . In addition, the permissive mode from the DR driving regulations was implemented. In this operating mode, the permissible speeds (switchable during the day 50, at night 15 km / h) were monitored without changing the basic settings for the train journey.

There were differences in line equipment between lines operated by the Deutsche Reichsbahn and Bundesbahn. At a previously announced speed of 40 km / h, the 500 Hz magnet remained effective for the DR, but not for the DB. While the DB was continuously equipping its lines, the retrofitting of the Reichsbahn lines was not pursued as consistently. In 1990 only 75 percent of the main lines and 10 percent of the branch lines were equipped with train control.

Austria

The Austrian Federal Railways (ÖBB) used Indusi for the first time in 1963 on the Salzburg – Freilassing route, which is operated according to German regulations . The Westbahn was equipped from 1965 and today Indusi is practically installed across the board. Not having an own train control system turned out to be advantageous, as it allows locomotives from Germany to run in Austria and vice versa.

Because of the limited space available at many Austrian train stations, the Indusi slipways protruded into the switch area, which meant that additional routes were excluded and the flow of operations was impaired. In order to improve the efficiency of the route network, slip-through paths have been dispensed with since the 1970s and they have been replaced by so-called protective paths , which are usually only 50 meters long. This sacrificed an essential element of the Indusi security philosophy.

500 Hz magnets are mostly missing in Austria. Instead, signal imitators are retrofitted with 1000 Hz magnets for exit signals that are far away from the end of the platform , which also help to prevent exit signals that indicate a stop.

With the aim of increasing safety, ÖBB made attempts with a train control system derived from SELCAB . However, in view of the development of the standardized European train protection system ETCS , the project was canceled. The LZB line train control is only used in Austria at speeds over 160 km / h.

Vulnerabilities

Thanks to its simple structure, the Indusi is very reliable and offers a great gain in safety at a reasonable cost. Because of the open- circuit principle of the transmission, the Indusi is not signal-technically secure . A track magnet that is faulty and ineffective can only be identified through periodic tests. However, this problem exists with all older point-like train control systems. Because Indusi on-board devices only monitor the speed at two points, there are further security gaps (see also: Punctual train control: Security gaps ). It is not always guaranteed that a train will stop within the slip path:

If the alert button is pressed after driving past the distant signal but no braking is initiated.
If, after a speed test on the 500 Hz magnet, the vehicle does not continue to brake.
When a train, after an intermediate stop, drives against a main signal indicating a stop and accelerates.

In the S-Bahn traffic, these security gaps are of greater importance. The Indusi I 60 is not designed for the high acceleration capacity of the S-Bahn multiple units . B. the accident in Rüsselsheim in 1990 showed. Because many S-Bahn lines run parallel to other railway lines, there is an increased risk of signal mix-ups.

The first case in the PZ 80 design was remedied by the braking curve internally simulated in the on-board unit instead of the appended speed test, which only acts in a punctiform manner, and by the permanent maximum speed monitoring in adjustable ten km / h steps that a vehicle equipped with it was behind the protective section behind comes to a stop at a signal indicating a stop. In the third case, an immediate emergency brake is triggered by a PZ-80 on-board unit by means of a 500 Hz influence if the driver has made an exemption from the previous 1000 Hz influence. Both innovations proved their worth and were incorporated into the PZB 90, but the train type setting in ten km / h steps and the permissive programs were not.

Further development

Indicator block for system PZB 90 and tachometer on a steam locomotive

modified data setter DES of the PZ 80R

In the LZB  80 on- board unit , the Indusi functions were no longer implemented with hard-wired electromechanical or electronic components for the first time in 1984 , but with the help of microprocessor technology and programmable software . This made it possible to monitor the speed not only at certain points in time or waypoint, but also continuously with a braking curve . The pulse relay of the earlier types was replaced by an electronic evaluation.

From 1990, the Indusi I 60R on-board unit was also available for vehicles without line control, an Indusi with microprocessor technology. On-board units of the type I 60R register the driving data in digital form for the first time .

After several serious accidents, a further development of the Indusi system was decided in the mid-1990s. The security gaps that the Indusi system has, especially in the S-Bahn traffic, have been closed by an expanded point-based train control system. The operation of the Indusi-Bauarten, which had developed differently during the German division, should be standardized. The new vehicle devices are no longer called Indusi , but with point-shaped train control (PZB) . On the one hand, new vehicle devices were developed, on the other hand, existing I-60 or PZ-80 vehicle devices were converted by implementing the PZB-90 operating program.

Only traction vehicles that are equipped with a type PZB 90 on-board unit are allowed to run on DB Netz routes that are equipped with point train control.

With regard to ETCS, Indusi and the successor system PZB 90 are managed as a class B system .

literature

Wolfgang Fenner , Peter Naumann, Jochen Trinckauf : Railway safety technology. Publics Corporate Publishing, Erlangen 2003, ISBN 3-89578-177-0 .
Lexicon railroad. Transpress VEB publishing house for transport, Berlin 1978.
Hans Pottgießer: Safe on the rails. Questions about the safety strategy of the railways from 1825 until today. Birkhäuser Verlag, Basel 1988, ISBN 3-7643-1992-5 .
Peter Schmied: Train control at the ÖBB. In: Swiss Railway Review . No. 4, Minirex-Verlag, Luzern 2000.
Christian Hager : Railway safety systems in Austria. Volume 2: Signals. Publishing house Peter Pospischil, Vienna 1994.
Frank Lademann: Dimensioning of encounter sections on single-track S-Bahn lines. Chapter operational and structural boundary conditions. (PDF; 300 kB) TU Darmstadt , 2001, accessed on April 10, 2013.

Web links

Commons : Punctual train control - collection of pictures, videos and audio files

Individual references, comments

↑ In the early days, in contrast to the current situation, the 500 Hz transmission was used for the travel lock function and 2000 Hz for the additional test point between the pre-signal and the main signal. The uses of both frequencies were later exchanged, because the higher frequency had proven to be more reliable and the driving lock function was seen as more important.
↑ Fritz Steiner: Security measures against driving over closed railway signals . Schweizerische Bauzeitung , Volume 103 (1934), Issue 24 (E-Periodica, PDF 1.9 MB) and Volume 103 (1934), Issue 25 (PDF 2.8 MB)
^ Ernst Kockelkorn: Effects of the new railway building and operating regulations (EBO) on railway operations . In: The Federal Railroad . tape 41 , no. 13/14 , 1967, ISSN 0007-5876 , pp. 445-452 .
↑ Bernd Kuhlmann: The Berlin outer ring . Kenning, Nordhorn 1997, ISBN 3-927587-65-6 , pp. 105 .
↑ To improve safety, the distances were increased from 150 to 200 meters to 250 meters from the 1990s.
↑ University of Stuttgart: Securing railway operations (online course), Chapter 4 Inductive train protection (Indusi) ; Retrieved April 10, 2013.
↑ Marco Wegener: www.indusi.de ; Retrieved April 10, 2013.
↑ The "U" operating mode is blocked on ÖBB traction vehicles. (Roland Smiderkal: Signalwesen in Österreich and Schweiz , 2003; accessed on May 23, 2013)
↑ However, this check only takes place once and does not have the consequence that the driver is permanently monitored for this maximum speed in the following speed-restricted section.
↑ Thales Group : AlTrac 6411 INDUSI I60R . (PDF 1.4 MB; accessed April 10, 2013).
↑ With the DR, permissive driving was the name given to an operating procedure in which trains are allowed to continue driving carefully on sight at stop-indicating or disturbed block signals of the automatic route block without special instructions from the dispatcher.
↑ German Bundestag (ed.): Answer of the Federal Government to the minor question from the MPs Stephan Kühn, Dr. Anton Hofreiter, Winfried Hermann, other MPs and the Alliance 90 / THE GREENS parliamentary group (...): Equipping the Deutsche Bahn AG route network with train control systems (PDF; 131 kB). Printed matter 17/4966 from March 1, 2011.
^ Roland Smiderkal: Signaling in Austria and Switzerland , 2003; Retrieved May 23, 2013.
↑ For the old I 60 without a microprocessor, the PZB-90 functions were implemented in a computer core newly developed by Deuta, which also takes over the electronic registration of the driving data. The display is made by a new indicator block. Siemens developed a conversion kit with a computer core and a new display unit for the PZ 80 installed in almost all former DR locomotives. The registration of the driving data of this PZ 80R, which was created in this way, either takes over the existing recording device on conventional writing strips or a new fully electronic device from Messma. Locomotives with I 60R could usually be upgraded to the PZB 90 system via software updates.

[1] In the early days, in contrast to the current situation, the 500 Hz transmission was used for the travel lock function and 2000 Hz for the additional test point between the pre-signal and the main signal. The uses of both frequencies were later exchanged, because the higher frequency had proven to be more reliable and the driving lock function was seen as more important.

[2] Fritz Steiner: Security measures against driving over closed railway signals . Schweizerische Bauzeitung , Volume 103 (1934), Issue 24 (E-Periodica, PDF 1.9 MB) and Volume 103 (1934), Issue 25 (PDF 2.8 MB)

[3] Ernst Kockelkorn: Effects of the new railway building and operating regulations (EBO) on railway operations . In: The Federal Railroad . tape 41 , no. 13/14 , 1967, ISSN 0007-5876 , pp. 445-452 .

[kuhlmann-1997-105-4] Bernd Kuhlmann: The Berlin outer ring . Kenning, Nordhorn 1997, ISBN 3-927587-65-6 , pp. 105 .

[5] To improve safety, the distances were increased from 150 to 200 meters to 250 meters from the 1990s.

[6] University of Stuttgart: Securing railway operations (online course), Chapter 4 Inductive train protection (Indusi) ; Retrieved April 10, 2013.

[7] Marco Wegener: www.indusi.de ; Retrieved April 10, 2013.

[8] The "U" operating mode is blocked on ÖBB traction vehicles. (Roland Smiderkal: Signalwesen in Österreich and Schweiz , 2003; accessed on May 23, 2013)

[9] However, this check only takes place once and does not have the consequence that the driver is permanently monitored for this maximum speed in the following speed-restricted section.

[10] Thales Group : AlTrac 6411 INDUSI I60R . (PDF 1.4 MB; accessed April 10, 2013).

[11] With the DR, permissive driving was the name given to an operating procedure in which trains are allowed to continue driving carefully on sight at stop-indicating or disturbed block signals of the automatic route block without special instructions from the dispatcher.

[12] German Bundestag (ed.): Answer of the Federal Government to the minor question from the MPs Stephan Kühn, Dr. Anton Hofreiter, Winfried Hermann, other MPs and the Alliance 90 / THE GREENS parliamentary group (...): Equipping the Deutsche Bahn AG route network with train control systems (PDF; 131 kB). Printed matter 17/4966 from March 1, 2011.

[13] Roland Smiderkal: Signaling in Austria and Switzerland , 2003; Retrieved May 23, 2013.

[14] For the old I 60 without a microprocessor, the PZB-90 functions were implemented in a computer core newly developed by Deuta, which also takes over the electronic registration of the driving data. The display is made by a new indicator block. Siemens developed a conversion kit with a computer core and a new display unit for the PZ 80 installed in almost all former DR locomotives. The registration of the driving data of this PZ 80R, which was created in this way, either takes over the existing recording device on conventional writing strips or a new fully electronic device from Messma. Locomotives with I 60R could usually be upgraded to the PZB 90 system via software updates.