German railway signalling
Railway signals in Germany[] are regulated by the Eisenbahn-Signalordnung. There are several signalling systems in use, including the traditional H/V system.
History
Reichsbahn
Originally, the railway company of each German state had its own signalling system. After these companies were merged into the German Imperial Railway, a common signalling system, the H/V system, was created based on two key types of signal. However, Bavaria was permitted to use its own designs of signal, with slightly different meanings, as part of the national scheme for many years thereafter.Main signals allowed the train to proceed or not. These signals were semaphores, whose arms had a circle on their right-hand end, and were painted white with red edges. There would be at least one arm, which meant "stop" when aligned horizontally and "proceed" when inclined upwards at 45 degrees. Up to two additional arms could be mounted below for different routes. They were inclined at 45 degrees upwards when a diverging route was to be taken, and aligned vertically when the main route was set. At night, a horizontal arm showed a red light, a diagonal arm showed a green and a vertical arm showed none.
Route signalling was changed circa 1930 to speed signalling. On a double armed-signal, one horizontal arm meant "stop", one inclined arm meant "proceed at line speed" and two inclined arms meant "proceed at reduced speed". Third arms were removed; in 1948, the green light of the lower arm was changed to yellow. This system is still in use today.
There were also distant signals to advise the driver as to what aspect the next main signal showed, so that he could slow or stop his train in time if necessary. Unlike in British practice, every main signal had its own distant; and each main signal-distant signal pair was worked from a single signal lever. German distant signals took the form of a yellow circular board with a black edge. If the board was visible, it meant that the main signal was at "danger". To indicate that the main signal was showing "clear", the board was flipped horizontally through 90 degrees so as to be practically invisible. If the main signal to which the distant applied was a double-armed one, then a yellow arm, bordered black, was mounted on the post below the disc. If the main signal showed "proceed at reduced speed", then as well as showing the disc, the arm was inclined at 45 degrees. At night, distant signals showed two lights, one diagonally left below the other. Reading downwards, green-green meant "expect clear", yellow-yellow meant "expect stop", and green-yellow meant "expect clear at reduced speed".
The first colour-light signals had come into use, but were not widespread when the country was divided in 1949. These signals simply showed the night aspects of the semaphore signals, and as such are not considered as a separate signalling system. Only the S-Bahn systems in Berlin and Hamburg were equipped with newly designed colour-light signals at that time, of the Sv system.
Post WWII
Two new companies were founded; the Deutsche Bundesbahn in West Germany and the Deutsche Reichsbahn in East Germany. The Reichsbahn kept the name of the old Deutsche Reichsbahn, to keep infrastructure and the right to operate trains in West Berlin. Both companies had their own regulations from then on and they continued separately until 1994 when the rail companies were reunified. Even today, the signalling systems of the two halves of the country differ, and although a new system has been created which will eventually become universal, the vast size of Germany's railway network means that different systems are likely to remain in use for many years to come. Even semaphore signals and mechanical signal boxes are still in use as of 2016, but with improved safety by using PZB and train radio.West
The Deutsche Bundesbahn mainly kept the H/V signalling, with colour-lights directly replacing semaphore signals; nevertheless, the signals did change their design over the years. One very early change was the inclusion of shunting signals into the main signal's head. This affected mainly exit signals. These signals show two red lights to disallow any train or shunting movements and a red-white-white combination to allow shunting movements only. Later the subsidiary signal aspects, which had their own head, were also merged into the main head. Therefore, several signals, whether main, subsidiary or shunting, can be merged into a common rectangular head.The signalling system didn't change much to allow Gleiswechselbetrieb. Only a new aspect was created to inform the driver if he was to be diverted onto the wrong line.
Several minor experiments with new signalling systems were made, but only one survived: the Augsburg - Donauwörth line, equipped with Sk-type signals. The signals still exist, and the new common signalling system were developed from these.
East
The Deutsche Reichsbahn adopted a new signalling system from the OSShD, an international organization of railways, mainly "Eastern" ones. H/V colour-light signals as built in the West did exist in some places in the GDR where they were installed before the war or in the first years after war, but most colour-light signals in the East were of the OSShD-designed Hl system. The EZMG system was installed on small secondary railroads and is similar to Russian light signals, however it uses Hl aspects.Reunification
Several signalling systems and two sets of railway regulations exist within reunified Germany. The regulations are being gradually merged to form a single set, a process still in progress. Most of the network will come under the control of centralized signal boxes; during this process complete lines generally change to the new common Ks signalling system. However, old-style signals are still installed on a few new lines for various reasons, usually if no surrounding lines have Ks-type signals. Even new semaphores are still occasionally installed, though now mainly as spares in semaphore-only areas. Currently no new signalling system is being developed; the current systems are perfectly adequate for today's operations. The next logical step will be a system without fixed signals, as current developments show: LZB, ETCSComparison to other countries
Systems similar to the H/V system can be found in Austria, Switzerland and Finland. Most of the aspects look identical, though the lamps are sometimes aligned differently. Austrian signals have one more and Swiss signals two more possible aspects. They can show a speed limit/announcement of 60 km/h and 90 km/h.Systems similar to the Hl system can be found in many former Eastern bloc countries.
The Ks system can be considered similar to signals in many countries, at least in appearance, as the colour codes: red for "stop", yellow for "caution" and green for "proceed" are commonly used in other countries.
The different signal systems
The signal systems H/V, Hl and Ks look quite different in appearance and differ in several details, but the safety principles are very similar, so the PZB safety system is used for all of them. Most instances of the additional signal types can be combined with all the signal systems, e.g.: Zs 3 appears with H/V and Ks, but Hl uses its own speed display; Zs 1 and Zs 8 appear with all of them, but in different shape.Lines without these signal systems exist:
- high-speed lines may operate practically without visible signals and PZB: they use Linienzugbeeinflussung or European Train Control System
- secondary lines under Zugleitbetrieb may use simplified signalling down to a Ne 1/Ne 2 combination, where movement authority is granted by phone/train radio communication
Punktförmige Zugbeeinflussung (PZB)
A safety system with functionality similar to PZB is mandatory for nearly every train and most railroad lines in Germany. As said, LZB and ETCS lines may omit PZB for them providing its safety functionality. Segregated nets like the Berlin S-Bahn are also often using different safety system.Normally, a main signal showing Hp 0 is protected by an active 2000 Hz magnet of the PZB train safety system which triggers forced braking if the train passes the signal. This may be overridden by the "Befehlstaste" if a Zs 1, Zs 7, Zs 8 signal or written order instruct to do so. In addition, a signal showing Hp 0 may be preceded by an active 500 Hz PZB magnet to trigger the train's PZB computer to enforce speed limits, according to the train's braking capabilities, to ensure that the train can stop before the main signal. Starting a train against a 'halt' signal without a special order is considered a safety violation and covered by the PZB "restrictive supervision".
Note: a "Lichtsperrsignal" that is used for shunting can show Hp 0, but is only protected by PZB magnets if it can be the start or end of a train movement.
Distant aspects that announce 'halt' or 'proceed with low speed', like Vr 0, Vr 2, Ks 2, Hl 10 etc., are normally accompanied by an activated 1000 Hz magnet of the PZB train safety system. Passing it triggers hidden timers in the vehicle's part of the PZB system, which first checks that the driver acknowledges the distant signal, then it supervises the braking. If the acknowledgement does not occur in time or if, at any point, the system detects that the train's speed exceeds the limits of a certain braking profile, it engages full brakes and enforces a stop of the train.
Main signal/distant signal (H/V) system
The most common system is the H/V system which consists of main signals and distant signals. Depending on the technology used in the signal box, these signals may be either semaphores or colour light signals. The colour lights show the same light patterns the semaphores show at night. The aspects shown here may be accompanied by Zs 2, Zs 2v, Zs 3, Zs 3v, Zs 6 or Lf signals in order to show speed limits or the choice of track that follows. A main signal is marked by a Mastschild to protect in case of a signal lights failure. The location of a distant signal is marked by an Ne 2 to prepare for the case where the signal lights fail.Hp 0: Stop
A main signal shows Hp 0 by a horizontal semaphore arm, one red light or two horizontal red lights. The signal requires the driver to stop in front of it.Vr 0: Expect stop
A distant signal shows Vr 0 by a yellow disc or two yellow lights. This signal indicates that its respective main signal shows Hp 0. As the signal is placed at braking distance from the main signal, the driver needs to apply the brakes immediately to stop the train before reaching the main signal.Hp 1: Proceed
Aspect Hp 1, indicated by one raised semaphore arm or a single green light, allows the driver to proceed at the speed indicated in his schedule.Vr 1: Expect proceed
Vr 1 indicates that the main signal shows Hp 1. On a semaphore, the yellow disc is flipped horizontally through 90 degrees, while colour-light signals show two green lights with the right one above the left one.Hp 2: Proceed at reduced speed
If both arms of the semaphore point up, or a green light is show vertically above a yellow light, the train may proceed but at reduced speed. Unless another speed is indicated by additional signals, the train must obey a speed limit of 40 km/h, unless instructed otherwise. Hp 2 indicates that the following track is free, but that the points/switches are set so as to make running over them at full speed dangerous.Vr 2: Expect proceed at reduced speed
Vr 2 orders the driver to slow the train to 40 km/h prior to reaching the main signal showing Hp 2. A different speed limit may be indicated by additional signals.Hl Signals
Hl-signals are used only in East Germany. The upper part of the signal is a distant signal, the lower part is the main signal. Signals can be found without the main signal section or without the distant signal section.Hl distant aspects
There is a green and a yellow light, both of which can flash or remain steady. There are four different aspects:Yellow: Expect Stop
Flashing Yellow: Expect Proceed with 40 km/h or 60 km/h
Flashing Green: Expect Proceed with 100 km/h
Green: Expect Proceed with maximum speed
Hl main aspects
There is a yellow and a red light on the signal, and additionally a bar with four green and four yellow lights below the signal.No Light: Stop, resolve situation by special procedures
Red: Stop
Yellow: Proceed with speed limit
If there is a speed limit it is shown by the green or yellow bar:
No bar: 40 km/h
Yellow bar: 60 km/h
Green bar: 100 km/h
Kombinationsignale
After the reunification 1990, a new signalling system using Kombinationsignale was designed to create a common system for East and West. While West Germany uses signals which simply show the night aspects of the semaphores, East Germany designed new light signals similar to those in other Eastern European countries. Since 2000, new signals have mostly been of the Ks system. There are exceptions; for example, H/V signals were installed on the light rail extension in Kassel post-2000 because the authorities wanted to avoid the risk of driver confusion on busy lines. The new Ks signals have three lights green, yellow and red, and have only three aspects. Basically, the signal meanings of the Ks signals match the ones of the H/V signals and vice versa, although the aspects may look different. The PZB and LZB technologies are used the same way as for H/V signals.Hp 0 Stop
One red light.The Ks system uses the same aspect for "stop" as the H/V system.
Ks 1 Proceed at given speed, expect proceed at given speed
One green light.Additionally a white number above the signal can reduce the speed. It shows the tenth of the speed limit from this signal. There may also be a yellow number below the signal showing the speed limit from the next signal, only shown if the speed limit at the next signal is reduced compared to the limit at the current signal. If such a yellow number is shown, the green light flashes.
Ks 2 Proceed at given speed but expect stop
One yellow light. Speed can be reduced from here as described for Ks 1.Additional signals
A number of additional signals provide additional information to the driver or modify the meaning of other signals. They are named "Zs" plus a number. Some of the aspect names differ in East and West; those shown here are the names used in West Germany. Several signals were introduced to speed up operation; they replace written orders which take some time, even if transmitted by telephone or train radio.Zs1 Ersatzsignal
Ersatzsignal = Subsidiary signalThree white lights aligned as a triangle, or one flashing white light.
Meaning: the train may pass the accompanying main signal with a maximum speed of 40 km/h. Details: If there is a dark distant signal at the same place, at most this speed has to be used until the aspect of the following main signal is visible, and until that, it must be expected that the latter signal commands "halt". If the main signal is a exit signal, this speed limit applies until the last set of points/switch has been passed by the complete train, after which regular speed is permitted. In case of entry and intermediate main signals of a train station, the speed limit has to be obeyed until after the next main signal or up to the usual stopping location. If several cases apply, the lowest speed given by any of them has to be followed.
This signal may be used when a main signal fails or cannot be set to a proceed aspect. One possibility is that one or more bulbs don't work, and the necessary aspect cannot be shown. For example, a signal which should show Hp2 could have a broken yellow bulb. It would therefore show Hp1. This would be dangerous because it implies to the driver that he could run faster than is safe, so the signal must show stop instead. Another possibility is that one of the 'proving' devices. In this case, the section of track or set of points/switch affected must be checked manually to ensure that everything is safe for the passage of trains, and the signal Zs 1 would be given.
Zs2 Richtungsanzeiger
Richtungsanzeiger = Direction displayShows one single white letter indicating direction. The letter is usually the initial letter of the next station or the next major station.
This signal does not give any specific command to the driver, as signalling safety devices mean that being diverted to the wrong route is not necessarily dangerous. It does, however, prove to the driver whether the route is correctly set up, and if the route is wrongly set he could ask the signalman to re-set the route before starting the train. Otherwise, if the route was set up wrongly, he would start the train, set off down the wrong route, discover the mistake, need to set back, have the route re-set, etc., all of which would waste a lot of time.
Zs2v Richtungsvoranzeiger
Richtungsvoranzeiger = Distant direction displayShows one single yellow letter, telling the driver how the route is set after the next signal.
Meaning: Expect Zs2
Zs3 Geschwindigkeitsanzeiger
Geschwindigkeitsanzeiger = Speed displayShows one white number indicating the tenth of the speed allowed from this point.
Usually used in combination with main signals. Zs 3 are used for variable speed limits for different routes. Permanent speed restrictions are displayed using Lf plates.
Zs3v Geschwindigkeitsvoranzeiger
Geschwindigkeitsvoranzeiger = Distant speed displayShows one yellow number indicating the tenth of the speed allowed from the point where the following Zs3 signal is found.
Usually used in combination with distant signals.
Zs4/Zs5 Beschleunigungsanzeiger/Verzögerungsanzeiger (obsolete)
Beschleunigungsanzeiger = Acceleration displayVerzögerungsanzeiger = Delaying display
Used to indicate the train driver that he should accelerate or slow down to optimize the occupancy of the line. A train driver could slow down to avoid a signal showing "Stop" for himself, or accelerate to avoid a stop for the following train. They became obsolete when in the 1970s the first phones could be installed on trains.
Zs6 Gegengleisanzeiger
Gegengleisanzeiger = Wrong line displayIndicates that the train will be driving on the wrong line from this signal on.
Used only on lines where wrong line working is frequent.
Zs7 Vorsichtsignal
Vorsichtsignal = Caution signalThree yellow lights aligned as a triangle pointing down.
Meaning: Train may pass this signal but must be prepared to stop at any obstacle. The speed has to be chosen according to visibility, but must not exceed 40 km/h.
Used only in combination with main signals.
This signal is used for the same cases as Zs1. The difference is that for a Zs1 it is checked for the driver that the line is clear, whereas at a Zs7 the train driver must check for himself that the line is clear.
Zs8 Gegengleisfahrt-Ersatzsignal
Gegengleisfahrt-Ersatzsignal = Against track crossing signal replacementThree white flashing lights aligned as a triangle or a flashing diagonal light
Indicates that a signal at danger may be passed when wrong line working is in force. If the signal guards points/switches the speed limit is 40 km/h; otherwise, the limit is 100 km/h to the next station. As with other 'wrong line operation' signals, this is only used where wrong line operation is frequent.
Zs10 Endesignal
Endesignal = Ending SignalThis Signal indicates that any speed restrictions given by Hp2 or Zs3 end with the rear of the train passing this signal.
Langsamfahrsignale
Langsamfahrsignale = Slow travel signalThere are several plates to display speed limits, of two basic types: signs showing the maximum speed and, where the speed limit drops, advance warning signs.
The Lf1, Lf4 and Lf6 plates are advance warning boards, while the Lf2, Lf5 and Lf7 announce the start of speed limits. The Lf3 plate marks the end of temporary speed limits, but the end of a permanent speed limit was not usually shown.
Changes as of 2007:
Lf4/Lf5 are obsolete and are being replaced by Lf6/Lf7;
An increase in speed limit will now always be shown by a Lf7.
Nebensignale
Nebensignale are signals that do not fit in any other category; some of them give hints rather than requiring action.Ne 1 Trapeztafel
Trapeztafel = Trapezoid boardMeaning: Stop here to await permission to proceed.
Trains must stop here to wait for visual or verbal signal to proceed. Found on lightly-used lines where telephone block operation is in force and at double-tracked lines at the left track at the entry to a station if no other signal is installed; it effectively replaces a station's entry signal.
Ne2 Vorsignaltafel
Vorsignaltafel = Distant signal boardUsed alone or in combination with a distant signal.
Meaning: This is a distant signal.
A main signal, shunting signal or a Ne1 will be found at braking distance. Unless a distant signal, distant signal repeater or main signal is visible, the train driver treats this signal as "Vr0 or Ks2: Expect Stop".
Every distant signal is mounted with a Ne2 plate to mark their position. Distant signal repeaters or distant signals mounted in combination with a main signal do not have a Ne2 plate.
Ne3 Vorsignalbaken
Vorsignalbaken = Distant signal beaconUsed to announce distant signals. Posted 250m, 175m and 100m before distant signal.
Generally 3 plates are used, but up to 5 may be used at hard-to-see locations. Fewer than 3 are used if the distance from the previous main signal is too small to install them all.
Ne4 Schachbretttafel
Schachbretttafel = CheckerboardplateUsed to indicate that a main signal is not in its usual position. This plate is posted where the signal would be if conditions were normal.
Ne5 Haltetafel
Haltetafel = Stop boardUsed to indicate where at the platform a passenger train should stop. It can be combined with additional signs indicating what types of trains should stop here, e.g. "240 m" for trains at most this length.
Ne6 Haltepunkttafel
Haltepunkttafel = Stopping point boardMeaning: Expect a stopping point within braking distance.
This is only used to announce halts that are not stations.
Ne7 Schneepflugsignal
Schneepflugsignal = Snowplough signalGives information to snowplough crews. A yellow or white 'V' shape indicates 'lower snowplough', an inverted yellow or white 'V' indicates 'raise snowplough'. These are placed to warn the crew to raise the snowplough so as to avoid hitting any obstructions at rail level, such as level crossings/grade crossings.
Schutzsignale
Schutzsignale = protection signals.These signals used to control only shunting movements, but nowadays, they apply to trains as well. Shunting movements do not leave a station whereas train movements do. These signals are sometimes combined with main signals, which is the reason why main signals sometimes have one red light and sometimes two. Historically, shunting movements were allowed to ignore main signals. They had to stop only at main signals with two red lights, because a double red light means Hp 0 and additionally Sh 0. When they were allowed to pass this signal, it showed a red and two white lights, still forbidding train movements. After a change, a red signal always means stop for all movements. Therefore, only one red light is needed, so single red lights will be used for new installations.
Sh 0:
- as light lignal: The earlier light signal Sh 0 is called Hp 0 nowadays. Originally, the light signal with the name Sh 0 had two white lights mounted horizontally. In conjunction with changing the lights to red, they received mast shields similar to main signals, serving as fall-back in case of their failure.
- as semaphore signal: A white circle with a black line horizontally across it, mounted on a black box. It means Fahrverbot, and all train and shunting movements must stop short of it. These signals are still in use by mechanical signal boxes. 'Black box' indicators fixed at aspect Sh 0 are commonly found mounted on buffer stops.
A white circle with a black diagonal line across it, mounted on a black box; or, two white lights aligned diagonally. It means "shunting allowed". But also train drivers must check that a Lichtsperrsignal that is to be passed shows this aspect and not Hp 0.
Sh 2:
A rectangular red plate with a white border used at the end of the track or where the line is blocked, for example by engineering works. It displays a single red light by night.
Catenary Signals/''Fahrleitungssignale''
All these signals consist of a blue diamond-shaped board with various patterns of white markings. As such, only the white markings are described in this section. As catenary signals, they apply only to electric trains.El1v
Two horizontally-aligned square white dots, on centreline of board. This warns the driver to switch off the locomotive's main switch.El1
Similar to El1v but with a horizontal line under the square dots. Locomotive's main switch must be off when this board is passed.El2
A square U-shape. Main switch can be turned on after this board.El3
Two horizontal lines across the board, about one quarter and three-quarters of the way down it. Warns driver to lower the locomotive's pantograph.El4
One horizontal line across the centre of the board. Pantograph must be down when this board is passed.El5
Vertical line through the centre of the board. Pantograph may be raised after passing this board.El6
Concentric squares of blue and white. Indicates 'stop for vehicles with raised pantographs'. This sign is most commonly seen at the end of the catenary.Examples
Example 1
Entering a stationLeft: Secondary line with minimum signalling
Right: Main Line with standard signalling