German and Austrian Signalling

The historical background, and an explanation of typical practices


  1. Introduction
  2. German Signals
  3. Austrian Signals
  4. Nebenbahn Signals
  5. The Schutzsignal
  6. The Zusatzsignal
  7. Other Signals
  8. References


A little history is necessary for the proper appreciation of railway history in Germany and Austria. Germany was unified only in 1871 by the federation of 39 independent states under the leadership of Prussia to form the Deutsches Reich. Each state had its own railway administration, and though they cooperated for through traffic, the practices of the several administrations were distinct. The principal administrations, the Länderbahnen, were those of Prussia, Bavaria, Baden, Saxony, Hesse, Württemberg, Oldenburg and Mecklenburg.

The first German steam railway opened in Bavaria on 7 December 1835 between Nürnberg and Füth with the Stephenson engine Der Adler. This is evidence of the early British influence on railway development. Other early lines were Leipzig-Dresden, of which the first part opened in the spring of 1838, Berlin-Potsdam, opening later the same year, as well as a line in Braunschweig. Most of the locomotives were from Stephenson's, with some from Sharp, Roberts as well as from the United States. The enterprises were mixed private and public, but gradually it was realized that railways were a public utility, like the post and later the telegraph, and they became state owned and administered. The largest administration was the KPEV (königliche preussische Eisenbahn-verwaltung), but Bavaria was not far behind, nor was heavily industrialized Saxony. In 1871, the German railways were about half privately-owned, half publicly, but mostly state managed.

The First World War, 1914-1918, and its aftermath, had a catastrophic effect on German railways. Not only were there reparations in the form of equipment (German locomotives were seriously coveted), but finances were in ruins and the government was unstable. On 1 April 1920, the Länderbahnen united to form the Deutsche Reichsbahn (DR). After the financial distress of the 1920's, this became the private Deutsche Reichsbahn Gesellschaft, until it was renationalized in 1937. The Second World War (1939-1945) was even more destructive, and in its aftermath Germany not only lost much territory in the East, but was split into two parts, the Bundesrepublik (BRD) and the DDR. In 1949, the railways in the BRD formed the Deutsche Bundesbahn (DB), while those in the DDR retained the old name of Deutsche Reichsbahn (DR). On the reunification of Germany in 1994, the initials DB were retained, but they now meant simply Deutsche Bahn.

Austria had a longer history. It consisted of the possessions of the House of Hapsburg, which was founded by the 7th century Ethicon I, Duke of Alsace, and took its name from a Swiss castle in lands conquered in the 12th century there. Rudolph I, b. 1218, was elected Holy Roman Emperor (1273-91), and secured Bohemia and other territories, founding the House of Austria. Most Hapsburg dominions were acquired by marriage and diplomacy, and some by wars with the Ottoman Empire. The indigestible Hungarians were accommodated by the founding in 1867 of the Dual Monarchy, or Austria-Hungary, in which the dominant Austrians and Hungarians lived side by side in harmony. The kingdom of Hungary, much larger than present-day Hungary, was surrounded by the Austrian Empire on north, west and south. This was the origin of the term kaiserlich-königlich (imperial and royal), or "kk", found in many acronyms. This state extended from Switzerland to Poland and Russia, from the Adriatic to the Carpathians, and from Saxony to the Balkans, with its capital in Vienna, and a sister capital in Budapest. Parts of Austria, Hungary and Bohemia were industrial, and mining was important in many areas, but Austria-Hungary was largely agricultural and wooded, with an abundance of "provinces."

The first Austrian steam railway was the Kaiser Ferdinand Nordbahn, opening in 1836 from Vienna towards Brünn in Slovakia, a small segment of the important route from the Adriatic port of Triest to the North Sea. In 1832, a tramway had been opened between Linz and Budweis, in Bohemia; the first segment dated from 1827. This was an important link, but it was horse-drawn, like many similar tramways of the era. Its gauge was 3 ft 7-1/2 in, converted to standard in 1869. It was extended to Gmunden in 1836, where steam was first applied in 1854. Horses lasted between Linz and Budweis until 1872. Railways were built with private capital, and were mainly radial from Vienna. One of the first, and largely an experimental venture, was the line to Baden, where British and American promoters vied for notice. An American-style wooden track and 2-2-0 Jervis locomotive were demonstrated quite successfully, but the authorities decided for the more substantial British technology. The Österreich-Ungarn Staatseisenbahn, despite its name, was private and connected Vienna and Budapest. The first part of it was the Wien-Raab railway, open by 1841. It was later called the Ostbahn.

The most important railway, however, was the Südbahn, which was to connect Vienna and Triest over the rigorous Semmering Pass. The engineer of this line was Carl, Ritter von Ghega (1802-1860), who succeeded very well. He visited the United States in 1842, examining in particular the Allegheny crossing of the Baltimore and Ohio, which then was just beginning construction. The Südbahn extended from Triest through Slovenia to Progerhof, whence lines went northwards through Graz and over the Semmering to Vienna, and northeastwards via the south shore of Lake Balaton (Plattensee) to Budapest. The Südbahn also owned the line from Kufstein through Wörgl and Innsbruck to Italy via the Brenner, part of the Munich-Rome link. Kaiser Franz Josef later had a connecting line completely in Austria built, over the difficult stretch from Salzburg to Wörgl.

Completing railways in the cardinal directions from Vienna was the Kaiserin-Elisabeth Bahn (KEB), now called the Westbahn, to Linz, Passau and Bavaria, as well as to Salzburg and Munich. In 1881 the government took over operation of the KEB, and in 1884 both it and the Kaiser Franz Josef Bahn (running northwest from Vienna to Budweis and Prag) were acquired by the state. In 1884, the state railway administration was reorganized into the kaiserlich-königlich österreichischen Staatsbahnen, or kkStB. Gradually, all Austrian railways were brought under this umbrella.

The First World War was fatal to Austria-Hungary. Centrifugal forces, as well as malicious interference by the victorious powers, destroyed the Dual Monarchy and reduced Austria and Hungary to their present dimensions. Romania, Italy and Russia helped themselves to morsels, and unfortunate arrangments were made in the creation of Czechoslovakia and Yugoslavia that finally became unglued at the end of the century. The destruction of Austria-Hungary was a political and human disaster, but was probably unavoidable in view of its great diversity.

Austria was left with the railways within its new borders. They became the Bundesbahnen Österreichs, or BBÖ. In 1938, the Anschluss transferred control to the Deutsche Reichsbahn and Berlin. Considerable efforts were made to bring Austrian railways into concordance with the DR. After the Second World War, the railways were reorganized as the Österreichishe Bundesbahnen, or ÖBB, as they now are. Traffic, which had been primarily north-south in the days of the Dual Monarchy, became primarily east-west. (Just the opposite happened in Germany after the Second World War.) The borders to the north and east became barriers, not gateways, though the Ostbahn remained an important international link. The DR did, however, operate a red and grey diesel train between Berlin and Vienna through Czechoslovakia that recalled sunnier days.

German Signals

The German word Weiche is fully analogous to the American term turnout, since weichen is what a wagon had to do to allow an opposing wagon to pass. It is not analogous to "points," so I'll use the word "turnout" in what follows. German signal regulations give symbols for every signal aspect, such as Hp0 for the stop aspect of a main signal, and even for the messages given by signs. These convenient symbols will be mentioned here as well. In German, mechanical signals, in particular semaphores, are called Formsignale. Signals whose aspects are displayed by electric lights are called Lichtsignale.

In the beginning, German railways distributed Bahnwäter along the line, corresponding to the "policemen" of British railways. These employees communicated with engine drivers by means of hand and flag signals. Unlike in Britain, the Bahnwärter were in communication with each other by means of an optical telegraph, adapted from the optical telegraphs then widely used for messages, such as the Chappe telegraph in France. This allowed the Bahnwäter to be spaced more widely, reducing the costs of the system. These telegraphs generally had two spatula-shaped arms pivoted at the top of the mast and operated by levers at the base of the mast. Only a small number of prearranged messages were sent, alphabetic or numerical codes not being used. These messages included notice of approaching trains with their directions, a command to stop all trains or cancel a previous signal, a call for a help engine, or an emergency signal to stop all trains immediately. By this means, either double- or single-track lines could be operated safely. Single-track lines were much more common on the continent than in Britain. The trains were mostly scheduled, but extra trains could also be run. Green signals at the rear of a train warned of a following extra, while signals on the locomotive identified an extra train. Optical telegraphs began to disappear after 1860, and were gone by 1885.

When the need was felt for communication between employees on the ground and engine drivers by a better means than hand and flag signals, the optical telegraphs were adapted to this purpose. Now they had only one arm, extending to the right of the mast as seen from an approaching train. A horizontal arm commanded "Halt!" while an arm raised at about 45° commanded "Fahrt frei!" (proceed). By night, a red light was displayed with a horizontal arm, and a white or green light with the raised arm. A signal at the entrance to a station ("Einfahrsignal") protected trains stopped at the station and admitted trains when desired. A signal at the exit of a station ("Ausfahrsignal") controlled the departure of trains after the points had been properly set for the route to be followed. These signals also provided valuable information to employees on the station. They were operated from the mast bases by the switchtenders, on advice from the Fahrdienstleiter. Distant signals were not used, since trains approached all stations under control, and normally came to rest there. Einfahr- and Ausfahrsignale correspond very roughly to British home and starting signals.

Optical telegraphs and the signals derived from them antedated the appearance of semaphore signals in Britain (1841). The British semaphore sigals were adapted from the land telegraph of Gen. Pasley, which had parallel arms rather than the spatula shape of the German telegraphs, and in which the arms could be concealed within the post for the Clear aspect. They were naturally three-aspect, with the arm depressed 45° corresponding to Caution. The arm extending to the right applied to an approaching train, as in Germany, which was a surprising choice considering that trains kept to the left on double track, not to the right, as in Germany. Such semaphores were never used in Germany. Signal colours, however, were exactly the same, with white for Clear, green for Caution and red for Danger (Stop). It became customary for Einfahrsignale to display green for Clear, reminding the driver to proceed with caution. Ausfahrsignale retained white for clear.

Although Germany did not adopt British semaphore signals, it did use the rotating target signals as developed in the 1830's, before semaphores. These were "closed" when the target faced the approaching train, and "open" when parallel to the track. This was the only satisfactory way to operate rotating targets. Earlier attempts to use red and white paint on opposite sides and to display one side or the other proved useless. When backlit, both sides appeared black regardless of the paint. These signals were used for many years, chiefly in the South. In Bavaria, the targets were painted red ane white, divided diagonally. By night, they showed either a red or a white light. Red discs with an opening in the centre were also used. These signals rotated about a vertical axis. They were used in the same applications as the semaphores, and were still common as late as 1881. Rotating targets that showed different shapes for the two aspects were not used in Germany, as they were in Britain.

Electrical signalling became possible by 1840 through the work of Steinheil in Germany and Wheatstone in England. The main problems that were overcome were the construction of long circuits by providing proper insulation, and the matching of batteries and magnet windings. By 1846, an electrically-released bell system was available that could replace the optical telegraph. For the details of these bells, see the article devoted to them. Around 1850, the Morse system of telegraphy reached Germany. The Morse code was adapted to the German language (becoming the modern Morse code) and the system was rapidly extended. The attractive feature of the Morse system was the recorder, which gave a physical copy of the signals transmitted, which could be translated by unskilled operators and served as a record. Soon, all stations were connected by the Morse telegraph, which was used for the exchange of messages relating to train movements. A German inventor developed an inking recorder, in place of the embossing recorder designed by Alfred Vail of the Morse associates.

The telegraph made the block system, suggested by Cooke in 1842 and widely applied in Britain after about 1855 (surprisingly, as a means of increasing track capacity as well as for safety reasons), very practical. Signalmen at the ends of a block could exchange messages admitting trains and reporting the block clear. In Germany, the signal used at block stations was just the optical telegraph with two arms, but now each arm applied to a different direction. Normally, the arms on both sides were horizontal, displaying Halt. To admit a train to a block, the corresponding arm was raised to 45°. The night aspects were red or white lights. When Lartigue in France developed his block system in 1875, he adopted these signals. In Germany, block signals were distinguished by having the arm for the opposing direction horizontal. For station signals, such second arms were dropped parallel to the post.

Many signal arms, discs, targets and so forth are observed to be of lattice construction or pierced with openings. This is often assumed to reduce wind resistance, but if the designers had this is mind, they were disappointed, since the reduction is small. The significant result was a reduction in weight, which was considerable for a semaphore arm, while not decreasing the visibility to an important degree.

In the early days, semaphores did not provide route information. This function devolved upon point indicators, which were made prominent. When set for a divergence, a green or green/white target, or a green light, were displayed. When set for straight through, the edge of the target or a white light were shown. If the divergence was to a track not appropriate for a through train, such as a stub siding or service track, a red target or light was shown. This is a useful convention that was never used in the U.S. or Britain. At large stations, where there were many possible routes for an arriving train, semaphores were sometimes erected at platform ends or suspended from the station roof. These Wegesignalen normally displayed Halt. When the switchtender had set the points for a route, he raised the signal at the platform end. This served as a signal to the man at the Einfahrsignal to raise the signal to admit the train. Of course, its driver could also determine the route by locating the Wegesignal. These signals were odd because they had no connection with the points, and did not protect a danger point. They were often mounted on the same mast as the departure signal for the track concerned, usually at a lower level. The first were installed at the Potsdamer Bahnhof in Berlin in 1870.

The route indication problem was attacked with the two-arm semaphore, which appeared in 1880. The second arm was normally parallel to the mast, just below the main arm. Using the main arm only, the aspects Halt and Fahrt frei could be displayed. The third aspect showed both arms at 45°, and indicated Proceed on Diverging Route. At first, the upper arm displayed a white light when inclined, the lower arm a green light. Then, at an Einfahrsignal it was thought best to display two green lights. Eventually, this was adopted for Ausfahrsignale as well, so that a red light, a green light, or two green lights in a vertical column were displayed. In 1893, a third arm was added so that a fourth aspect could be displayed, and two diverging routes could be distinguished. These multiple-arm semaphores were not adopted in South Germany. Bavaria only adopted two-arm signals in 1907, and then to indicate a speed restriction, not a route. Three-arm signals were never used in Bavaria. After 1893, semaphores displayed a red light, or from one to three green lights in a vertical column. Since this was route, not speed signalling, Wegesignale had to be retained at large stations.

One final use for semaphores, or "signals on a mast" as they were known, was to protect points of danger not at a station, such as level crossings with other railways, junctions and movable bridges. These were called "Deckungsignale". At first, distant signals were not used with them, nor with block signals. They were moved forward enough to provide a safe clearance distance, and passing them at Halt was expressly allowed. Distant signals were also not used with station signals, since trains either approached them under control or were stopped when they were accepted. It seems that no special steps were taken to protect a train stopped at an Einfahrsignal from following trains, as was the case in Britain and France. Possibly, one train was not permitted to follow another as freely in Germany, or the Bahnwärter would serve as flagmen. Nevertheless, distant signals, called Vorsignalen, begain to be erected after 1870. By 1898, 38% of 20,000 stop signals were already provided with Vorsignale. After 1901, block signals had to have Vorsignale, and after 1902, Einfahr- and Deckungsignale. Only after 1929 were Vorsignale recommended for Ausfahrsignale for stations at which trains passed without stopping, and only required after 1938.

The term "Hauptsignal" for the semaphore stop signal was officially adopted in 1907. Until 1935, signal aspects were numbered. In that year, new designations consisting of letters and numbers were adopted. For example, Hp0 is Halt, Hp1 is Fahrt frei, and Hp2 is Langsamfahrt, displayed by a semaphore with one or two arms.

Semaphore signals, Hauptsignale, governed train movements only, not shunting movements. Trains were under the control of their crews, while shunting movements were governed by men on the ground giving hand, lamp or whistle signals. Before the introduction of interlocking, this was convenient and logical. However, interlocking required that routes be protected from conflicting movments of any kind. To control movements of any kind on any track, not just on main tracks, Sperrsignale were introduced in 1913. The original, and still familiar, form of these signals was a black bar pivoted at the centre, seen against a milkglass disc that could be illuminated from the rear at night. When the bar was horizontal, the signal could not be passed. When the bar was diagonal, movements could pass it. This signal was very different from a Hauptsignal, and clearly visible from short distances. A Sperrsignal was often placed directly in front of a Hauptsignal. When the Hauptsignal was at Fahrt frei, the Sperrsignal was diagonal, to avoid conflict. Sperrsignale were also found alone on tracks not used by service trains. The two aspects could also be placed on two sides of a rotating housing, with a lamp inside.

Another solution to the problem was the Wartezeichen, a large yellow W with a black border, often illuminated by a spotlight. Any shunting movement could not proceed past this sign without explicit permission to proceed. In some cases the Wartezeichen was located on top of a Sperrsignal, and special rules governed. They seem to have been introduced around 1931. Originally, a three-light Vorrücksignal was used with them, with one white light at each end of the W, and one beneath it.

When light signals were introduced, they were based on the night aspects of the mechanical signals. The distinction between Hauptsignal and Vorsignal was strictly maintained, the Vorsignal lights displayed beneath the Hauptsignal lights when they were combined on a single mast. The light Sperrsignal was introduced in 1944. The Stop aspect was shown by two red lights in a horizontal row, while the Proceed aspect was given by two white lights on a diagonal rising to the right, on a square black background. A new aspect was created for the Hauptsignal, Hp00, in which two red lights were displayed horizontally. This meant Stop for both train and shunting movements. To permit shunting movements to pass, the right-hand red light was extinguished (creating aspect Hp0), and two diagonal white lights were shown beneath the main signal. When used with a semaphore, the light Sperrsignal was for a time extinguished when the signal showed Fahrt or Langsamfahrt. Later, however, the two diagonal white lights were shown. This is a good idea, since a light signal may be extinguished by an electrical failure as well as by intent. In the U.S. and Britain, an extinguished light signal is considered as displaying its most restrictive aspect.

The distinctive Vorsignal was a green disc with a white rim that rotated about a horizontal axis. A green roundel in the disc displayed a green light by night to show "Halt erwarten" if the main signal was at Halt. When the disc rotated to a horizontal position, the white light of the lamp was displayed. This aspect was "Fahrt erwarten". This gave rise to an inconsistency. A single green light here was restrictive: expect Stop, while at a semaphore it meant Proceed. This problem was not resolved until the adoption of the Saxon State Railways two-light Vorsignal in 1910. This had the same circular target revolving about a horizontal axis, but displayed two green lights rising to the right for "expect Proceed" and two yellow lights rising to the right for "expect stop". The disc was now yellow with a black/white rim. This represented the definite introduction of yellow as a signal colour meaning Caution, instead of green, which was now associated definitely with Proceed. Bavaria did not follow suit, retaining green for caution and white for Proceed until 1922, after the formation of the Deutsche Reichsbahn.

The new Vorsignale also presented an inconsistency. The main signals could display up to four aspects, but the two-light Vorsignale only two. No doubt with misgivings was the double green "Fahrt erwarten" used with any of the three proceed aspects, while the double yellow "Halt erwarten" was logically reserved for the stop aspect alone. This problem was resoved with a new Vorsignal that had an indicating arm (Zusatzflügel) below the disc, painted red and white like a signal arm, that pointed to the right with the disc displayed to indicate "Langsamfahrt erwarten". The night aspect of two yellow lights was augmented by a green light directly below the right-hand upper yellow light, but higher than the left-hand lower light. This signal was introduced in 1933, after the two- and three-arm signals were interpreted as requiring a reduced speed over the diverging route, called "Langsamfahrt". On any segment of line, only two-aspect or only three-aspect Vorsignale could be used. On three-aspect segments, Vorsignale preceding two-aspect stop signals had a fixed indicator that was actually a dummy. By this time, the familiar Vorsignaltafel had been introduced, with the black arrowheads point-to-point on a white background that made the location of a Vorsignal clearer, since it effectively disappeared when the disc was horizontal. Three-aspect Vorsignale were designated by a black equilateral triangle with a black dot in its centre placed on top of the sign. To permit higher line speeds, the distance between a Vorsignal and its stop signal was increased to 1000 m around 1933 for lines with a maximum speed of 160 km/h.

In 1948, the three-arm semaphore was finally abolished. It had been used only in Northern Germany, and was always a route signal. At the same time, the light for the lower arm of a two-arm signal was changed to yellow from green. These signals then showed red, green or green over yellow. In 1949, the new Vo-44 Vorsignal changed the indicator arm colour to yellow with black border, and the "Langsamfahrt erwarten" aspect changed to green over yellow. With these changes, mechanical signalling attained its final form, which became very familiar. Many of the developments we have discussed up to now on an historical basis will now be explained again in what follows.

The very earliest steam railways, those of the 1830's, used hand signals with red and white flags or lanterns, and the whistle of the engine (introduced 1833), to communicate between moving trains and the ground. Red meant stop, as it did in road traffic. In 1841, a conference of British railway managers in Birmingham, hoping to forestall Parliamentary interference, formulated safety regulations under the leadership of Henry Booth, Secretary of the Liverpool and Manchester. The signal colours red for danger, white for safety and green for caution were agreed upon. These choices were nearly universally followed worldwide until around 1900, when a movement to replace green by yellow for caution, and white by green for safety gathered momentum. The main reason was the proliferation of bright white lights in the environment. Green was adopted for safety quite early in some places, but the adoption of yellow for caution was delayed. Either caution was eliminated, or the simultaneous display of green and red was substituted, in many cases. The change to the new colours was not complete until the mid-1930's. The yellow that was adopted was typically an orange-yellow or amber colour, of which the familiar German signalling yellow is an example. At the same time, the green altered from a yellowish-green (intended to get the most brightness from a flame) to a bluish-green easily distinguished from the new amber under most atmospheric conditions.

German and Austrian practices were by no means identical, but they shared certain characteristics. Let us first explain the origin of the semaphore signals that display two inclined arms, and two green lights, very unlike anything in America or Britain. As we have noted, railway development in Germany and Austria took place slightly later than that in America and Britain, so that precedents were available, and were carefully examined. At first, hand signals--flags and lamps--sufficed to inform engine drivers. In the 1840's, increased traffic made stations points of danger, and fixed signals became desirable to control trains. These signals governed the entrance to stations, or junctions where trains could take different routes. By the mid-1840's the semaphore had already been introduced and was spreading rapidly in Britain. To protect a junction, two arms were provided. The top arm governed the direct route, while the lower arm governed the diverging route (this was the commonest situation). Normally, the arms were both horizontal and showed red lights by night. To permit a train to take the direct route, the upper arm was lowered. By night, a green light (meaning at this time, proceed with caution) over a red light was shown. If the train was to take the diverging route, the lower arm was lowered, and by night red over green was displayed. This was accepted in Britain as good practice, and such signals were also used on the Austrian KEB (Westbahn) 1879-1888, the upper arm displaying red/white, the lower, for a divergence, red/green.

In Germany, however, there were objections to the driver's having to pass a stop signal, either a horizontal semaphore arm or a red light, in either case. This is an objection that has turned up in signalling theory again and again, though in Britain and America the practice of showing numerous superfluous red lights and horizontal semaphore arms meets with few objections. Recall the large signal gantries in Britain with a score of semaphores at stop and a swarm of red lights, with one arm lowered and one green light to permit a train to proceed. Or, in America, a signal bridge at an important junction with stacks of three red lights one above the other. When a train is to proceed, one of these many lights winks into green. The Pennsylvania Railroad position-light signals omitted any stop aspect that was not required, and the Baltimore and Ohio color-position-light signals never required a driver to pass a red light. Modern British MAS signals also share this characteristic.

What was done in Germany was to hide the lower signal arm by placing it vertical, in line with the mast, and displaying no light, when it was not to be used. Then, the top arm showed stop when horizontal, displaying a red light, and proceed on a normal-speed route when inclined at 45°, displaying a white light. To signal the diverging route, both arms were displayed at 45°, and both showed white by night. This neatly solved the problem of passing red lights, and gave the driver a distinctive indication of route. This was extended to the case of three arms, which could show one, two or three white lights by night, if there were three routes to be governed. These signals could be seen as late as 1950.

When signal colours changed after 1910, green replacing white and yellow replacing green, the colours displayed by the semaphores changed accordingly. Now one red was displayed for Halt, one green for Frei, and two greens for Frei mit Ablenkung or Langsamfahrt. The semaphore signal is called a Hauptsignal, used as an entrance or departure signal at stations, or to protect points of danger. Upper-quadrant semaphores were always used in Germany, not the lower-quadrant signals typical of Britain and America. These signal arms returned automatically to horizontal by their own weight. They were typically made from enamelled stamped steel. Signal masts painted white-red-white identify signals that could only be passed by written authority or the ersatzsignal when unable to be cleared. Yellow-white-yellow stripes identified signals that could be passed at restricted speed under such conditions.

Eventually, it was concluded that it was better for a signal to indicate the safe speed than the route. One arm diagonal, or one green light, would indicate no speed restriction. Two or three arms would indicate a speed restriction, Langsamfahrt. Two arms could prescribe a speed of 60 km/h, and three 40 km/h, speeds corresponding to the medium and slow speeds in America, as prescribed by rule. However, proliferation of Dreiflügler was not wished, so it was settled that two arms meant 40 km/h in the absence of other instructions. For a different speed, a speed limit sign would be displayed on the signal mast. With speed signalling, Langsamfahrt allowed progress on any slow-speed route. If it was necessary to know the route, a lighted indicator was provided to give this information. For the night indication, the lower green light was replaced by a yellow light in this case. The lower green was retained for 60 km/h. Therefore, semaphores usually came to display red, green, or green over yellow, and these colours were retained in colour-light signals, which still display the colours of the semaphore signals today. The aspects are shown in the diagram at the right.

The route indicator has now been replaced by a speed indicator, showing a number (the Kennziffer) that gives the allowed speed when multiplied by 10. That is, a "5" means 50 km/h. Numbers 7-12 are used with Hp1 (Fahrt) and 1, 2, 3 and 6 with Hp2 (Langsamfahrt). In Germany, the speed permissible at the location is given in white lights, in an equilateral triangle with point down. An advance speed indication is presented in yellow lights in an equilateral triangle with point up. In Austria, the speed indicator is rectangular, 500 x 700 mm, and shows white lights.

German signals are usually placed to the right of the track, 3100 mm from the nearest rail, or directly over the track governed on a signal bridge, and the semaphore arms point to the right. When a semaphore cannot be located in the usual position, the Schachbrettafel (chessboard table) shown at the left is placed near it. This is most often seen at signals at the left of the track governed. In Austria, such signals are not specially distinguished. A white equilateral triangle standing on its point on top of a signal or sign is a general symbol for short braking distance.

It is interesting to note that in America, route signalling with multiple arms evolved into speed signalling with three three-aspect arms, roughly corresponding to high, medium and slow speed routes, the lowest arm usually shorter than the top two. Colour lights gave the same aspects as the night aspects of semaphores. The corresponding speeds were specified by rule. Medium speed was usually 30 or 40 mph, slow speed 15 or 20 mph. Proceed on a slow speed route was then red over red over green, for example. The aspect yellow over green over red was Approach Medium, "approach the next signal at medium speed." Red over yellow over red was Medium Approach, "proceed at medium speed prepared to stop at next signal." See Colour-Light Aspects for a complete list of aspects. In Britain, route signalling always prevailed, with one arm for each route on a separate mast. Both practices involved a large number of superfluous red lights that had to be ignored by a driver. In modern colour-light signalling there is only one main arm with four aspects, with the route indicated by a row of white lights at one of six angular positions. The driver's route knowledge provides the permissible speed, though cutout numbers with arrows indicated the speeds in many cases (this was an LNER practice retained into BR days).

Around 1873, the need was felt for an advance warning if the semaphore was at stop, so that the driver could stop the train in season. This gave rise to the Distanzsignal, as in France and Belgium it had to "advanced signals." These were signals placed a sufficient distance in rear of a stop signal to protect a train that had been stopped there. A driver was expected to approach an advanced signal under control, and originally even to stop there if the signal was displayed, before proceeding with caution. Later, the driver was supposed to get his train under control as soon as practicable at the advanced signal, but not to stop there, simply to proceed with caution to the stop signal, looking out for any train ahead. In France, the advanced signal was a red disc, the disque rouge, and in Belgium it was a red rectangle. These were on vertical axes, so the disc or rectangle could be turned to display its face when "on" but only its edge when "off." That is, the signal became practically invisible when the track was clear. This did not trouble railway minds in France, but did in Britain and Germany, where some positive proceed signal was thought desirable.

In spite of this, when German railway engineers were looking for some kind of advanced signal, a disc was chosen, in order to be as much unlike a semaphore stop signal as could be. This disc rotated about a horizontal axis, so that it presented its full face when "on" and only its edge when "off", and it was horizontal. The horizontal disc has some disadvantages, as collecting snow and ice in cold weather, but has the advantage that it looks the same from all directions. The orientation of a vertical disc might not be clear from around a curve. The disc was painted green, the colour of caution, with a border of white. In Austria, a similar decision was made, but the signal was square, not round. This new signal was called a Vorsignal, and only gave information about the Hauptsignal ahead, like an American or British distant signal. In order to make the signal more visible when it was "off" and showed only the edge of the disc, a Vorsignaltafel, a large sign consisting of two chevrons placed point to point, was erected. The chevrons were originally green on a white background, but later were black on white. If the braking distance between the Vorsignal and the Hauptsignal was less than the normal braking distance for the line, perhaps 1000 m, a triangle was shown above the Vorsignaltafel. The light vorsignal adds a small white light on the upper slanting edge to indicate this, and is then called a vorsignal repeater. The Vorsignalbaken counted down to the signal; they were placed at the distances shown in the figure.

The small arm below the Vorsignal disc, or Zusatzfl&uum;gek allows an additional aspect, "Langsamfahrt erwarten." In Austria, the Zusatzflügel was not used, and the Vorsignal lights were single, not doubled. Many Vorsignals erected in Austria during DR days were later "Austrianized" in this way. Originally, of course, the disc was green, not yellow. The yellow used in German signalling after 1910 was a rich orange-yellow, not a pure yellow as shown in the diagrams.

The signals shown in the figure at the right are generally known as Gleissperrsignale, or "track blocking signals". The upper examples are mechanical signals, the lower ones light signals (of which there several types). They are indeed used at Gleisperre, "derails", as low signals, but this is the only connection. When the bar is horizontal, all movements on the track ahead are forbidden (for trains as well as shunting movements). The light signals originally showed two red lights, but since 1999 only one red light is necessary. When the bar is inclined, the restriction is lifted, but a movement is not necessarily authorized. In general, this must be done by the person in charge of shunting movements, or by the clearing of the hauptsignal. A shunting movment is authorized, however, if a square white plate with black border, standing on a corner, is displayed at the foot of the mast or somewhere else convenient. For light signals, the same is indicated by a white disk with a black ring painted on the signal face. The mechanical signals orginally used a box rotating about a vertical axis, and some low signals still are constructed this way. Note the aspects shown to the rear of the signal. When light sperrsignale were introduced, the lower light was removed, to avoid any confusion. These lights are milk glass, showing white by day and a light by night. The main circular background was originally lighted from inside, but now is usually a reflecting screen. The signals are not intended to be sighted from a great distance or by trains moving at speed.

A large variety of signals exist that apply to shunting movements, not train movements on main tracks. Each type of train obeys its own signals. At the left, a hauptsignal with a shunting signal is shown. The aspect Hp00 forbids both train and shunting movements. When one red light only shows, with the two diagonal white lights, shunting is allowed past the signal to some agreed limit. The route is protected by signals from inteference when this aspect is displayed. Shunting movements may also be forbidden by two horizontal white lights in Gleissperrsignale placed on shunting tracks. A very common older form was the Kastensignal, a black box with a translucent disc on one side, illuminated from inside by night. The black bar could be horizontal to forbid shunting, or inclined at 45° to allow it. These existed in high and low forms. A sign looking like one permanently at halt was used at the ends of tracks.

A distinctive signal that is often seen around stations is the large orange-yellow W, or Wartesignal or Wartezeichen (RA11), that takes the place of a shunting signal. It may be illuminated at night by a small spotlight. It is grey on the back. A shunting movment must not proceed past the wartesignal except on hand signals of a shunter or verbal instructions. The wartesignal may also have two small white lights to display the aspect Sh1 like an ordinary shunting signal, to authorize a movement. Earlier, three lights were used that formed a V (vorrücken) for the same purpose. This signal originated in Germany, but has spread to Austria.

An interesting signal of the Bayerische Staatseisenbahnen that survived until recently was the Ruhesignal, illustrated at the right. In addition to "Halt" and "Frei", it displayed "Ruhe", Ru 201, which meant that train movements on the track concerned would not take place, and the track was free for shunting. The blue light that was the night aspect could be displayed in both directions if necessary. The square plate shown in the figure with the red letters Ru and a red border and white background was displayed on the mast below the signal number plate. A number of these signals could be seen at Freilassing as late as 1973. Another Bavarian curiosity was vorsignal discs mounted on the hauptsignal masts that folded around a 45° line to appear like a Bavarian semaphore arm inclined at 45° to display Fahrt erwarten. They were originally green, later yellow.

The signal at the left is often seen at platforms, usually beneath the canopy where it is visible to the driver, or mounted on light poles. It is controlled from a switch box available to the platform staff. A static brake test must be made at the initial station, and whenever cars are added or subtracted from the train. The three white lights tell the driver when to apply and release the air brakes, while the platform staff checks that all brakes apply and release properly on all cars. When this is done, the three white lights are displayed. These signals are denoted Zp6-Zp8. When the train is ready to depart, the green light is displayed. Of course, the driver must check his signals to see if he can indeed start. There have been incidents in Britain where drivers have started off impulsively on seeing the green departure light, against their platform starter. Another right away signal is a ring of 8 small green lights, Zp9, displayed only when the departure signal is clear. This recalls the green-bordered white disc guidon used for giving the starting signal by hand, also called Zp9. Having started, the driver must make a running brake test as well. Curiously, where the lights are not available, one, two or three bangs on the buffer beam with the carman's hammer have the same meaning.

Signs are used to inform the driver of an electric vehicle when to open the main contactor for a change in power phase or supply, and when to raise and lower the pantograph for a section of de-energized, grounded contact wire (when men are working in the section). The signs are blue and white, as shown, and may be permanent or portable. The warning signs are located 300 metres in rear of the action signs, which are located 30 metres in rear of the significant points. The end of contact wire sign is 10 metres before the end of the wire. When one route beyond a turnout has no contact wire, an arrow below the corresponding end of contact wire sign is accompanied by an arrow pointing in that direction, or upwards if both directions are unelectrified. The arrow is white on a blue background. These signs are quite generally used, not just in Germany. The warning of switch out ahead is not used in Germany.

Austrian Signals

The Austrian semaphore signal is designed on the same principles as the German, but the arm is rectangular and pierced with 10 slots. The arm is 7565 mm (25 ft.) above the rail level, 1800 mm (6 ft.) long from the axis to the end, and 300 mm (1 ft.) wide. The axis for the second arm is 1250 mm below the upper. The aperture for displaying the red light is 400 mm from the axis, and is 246 mm in diameter overall. The arm is raised by a two-ended "security mechanism" to which the two operating wires are attached. Should a wire break (and its tension disappear) the arm falls by gravity to horizontal. The edges of the arm are painted red, with the middle white. The illumination was originally with mineral oil, then propane gas, and some were electrically illuminated later. The propane tanks allowed six weeks or two weeks burning time, depending on size. When displaying Halt, the two arms on a two-arm signal cross, unlike the arms on a German semaphore.

One often reads in connection with signal arms and other surfaces used in signalling that the piercing is for the purpose of reducing wind resistance. Perhaps the designers may have had this in mind, but it does not apppear that wind resistance is much reduced in this way. The benefit is much more likely to be a reduction in weight, which reduces the force necessary to operate the signal. Piercing reduces the weight while preserving the visibility of the object.

Many Austrian semaphores were later fitted with German-style enamelled arms with the circle ends , and this became standard. On two-arm signals, the circle on the end of the lower arm was over the axis of the upper arm, while in Germany it would be below it. Also, Swiss-style square vorsignals were also used after 1954. These had two yellow lights above horizontally, and two green lights below inclined, and could display four aspects.

The Austrian Vorsignal was rectangular, 1000 x 800 mm, its centre 3918 mm above rail level. The yellow, originally green, rectangle was surrounded by a black border, and that by a white border. The yellow and green lenses were on a spectacle that moved up and down in front of the lamp, 3000 mm above the rail. Vorsignaltafeln were abolished in Austria in 1980. It was thought that the vorsignalbalken provided sufficient notice. Later, some vorsignals were given reflective surfaces instead of illumination. When "off", a green rectangle was seen.

Light signals were introduced in 1926. Their economy was a great help to rebuilding Austria's railways after the First World War. The type of signal was shown by the shape of the background. A round top identified a hauptsignal, a flat top a vorsignal (in addition to the vorsignaltafel), and a pointed top a verschubsignal. The colours of the lights were identical to the night aspects of the formsignals that preceded them. The hauptsignal is shown with green over green, but green over yellow was also possible. The combination signals are typical, but the relative heights of the two signals differed. The combined haupt- and vorsignal shows Frei, Halt erwarten. The combined haupt- and verschubsignal shows Zughalt, Verschub erlaubt. Note that the colours of the verschubsignal are white and blue, so they do not conflict with the colours of the hauptsignal. The mechanical verschubsignal was a blue square on a point.

The newer light signals are shown at the left. The colour of each light is shown; of course, they would never all be lighted. The four lights in the hauptsignal can be in groups of two, one above and one below. Only the lights that are required are installed. There are cover plates at the unused apertures. As can be seen, these signals approach the German signals more closely than the earlier Austrian light signals. A small blinking red light on the newer hauptsignal is a Vorsichtssignal. It commands moving at restricted speed to the next hauptsignal, in cases when the state of occupation of the track cannot be determined due to signalling problems. In Germany, this is given by three yellow lights in a small V (Zs7). It could also be a blinking white light, in which case it would be an Ersatzsignal, allowing a driver to pass the signal at stop if it is out of order. These signals are different in Germany, and will be described below. On the older hauptsignal, there were originally two horizontal white lights on the verschubsignal. Since they were redundant, they were removed in 1980. In the centre is the new standard vorsignal, like the ones found in Switzerland, and introduced in 1954. Often, the vorsignal is mounted on the same mast as the hauptsignal, and below it. There may also be a lighted speed indicator applying at this signal, or speed pre-indicator for the next. This is more flexible than simply prescribing 60 or 40 km/h by rule or a sign, as was originally done. The speed indicator is mounted above the hauptsignal, but below the vorsignal. It may use small incandescent lamps, or fiber-optic technology. One signal mast may have hauptsignal, vorsignal, and two speed indicators.

Some shunting signals are shown at the right, in their two aspects. The signal farthest to the right is the Kastensignal, or box signal, mentioned above, which is very common in Germany, often found in connection with semaphore hauptsignals. When the bar is diagonal, it permits shunting past the hauptsignal at stop to the shunting limit. In Austria, it is equivalent to the middle signal that shows two white lights, horizontal to forbid shunting and diagonal to allow it. On the most recent light signals, the shunting signal is reduced to the diagonal pair of white lights on the signal head that permit shunting. Otherwise, they are dark. On older light signals, the shunting signal is placed below it. At the left is a Schutzsignal, that differs in that the horizontal lights are red (now there is only one red light). When these red lights are lighted, the signal must not be passed. There are some subtle differences between these secondary signals as used in Austria and Germany, but using the same apparatus. I may not be correct in some instances, but the general principles should be clear.

When a hauptsignal cannot be seen from the usual distance, as around a curve or through a short tunnel, a signal repeater or Nachahmer is used in Austria. The type illustrated uses small lights in rows of four, displaying the three aspects shown. Another type uses translucent bars illuminated from behind. The two aspects for "frei" and "halt" are familiar. The third aspect is derived from an experiment in modifying a single-arm semaphore to display three aspects, by depressing the arm instead of showing a second arm. This experiment was not followed up, but left a trace in this signal. In Germany, the Vorsignal is repeated instead, showing a small white light to upper left. Signal repeaters are quite often found in British signalling, and are used in Belgium as well, where they display only two aspects.

The 1996 signal regulations made many significant changes, resulting in a general simplification and increasing departures from traditional German practice. An important change was the extensive use of reflectorized surfaces, made practial by the bright headlights that had become general. Lamps were removed from semaphore haupt- and vorsignalen, as well as from switch indicators. Reflectorized surfaces are very satisfactory when the light source is near the observer, as it is in a locomotive cab, but, of course, become invisible when they are not illuminated.

Another change is the elimination of the shunting signal at a hauptsignal at stop. A red light means stop, for both train and shunting movements. Where a shunting signal is used at a hauptsignal, or at a wartesignal, it must permanently display "Verschubverbot aufgehoben" or shunting allowed. The signal can be passed only if it displays "Proceed." This clearly eliminates having shunting movements passing Stop signals, which is probably the motive for the change. I have not seen this in practice, and thinking about it brings up a certain uneasiness. How "calling-on" aspects are displayed is not clear, since in this case a clear hauptsignal is definitely out of place. The signal regulations do not mention calling-on signals, nor can a hauptsignal display "proceed at restricted speed." Since a shunting signal authorizes passing such a signal, and now since any shunting signal must display a constant "shunting allowed," it is not clear what is intended. This is a rather significant change of practice, if I have interpreted it correctly. In my mind, I tend to distinguish movements into a block from limited local movements. It is more difficult to assure that the block is clear to its far end, including clearance, than simply that the movement is protected within local limits.

Nebenbahn Signals

In both Germany and Austria, branch-line and local railways serving rural areas were kept open for social reasons much longer than in Britain and America, where such service disappeared after World War II. These light railways are called Nebenbahnen, and are characterized by moderate speeds and simplified operational procedures. Where the maximum speed is 50 km/h (30 mph) or lower, ordinary signals can be dispensed with, and replaced by signs serving equivalent purposes. Some of these signs are shown in the figure. Before World War II, these signs were not used in Austria. They were imported during the DR years, and retained as useful additions. There are slight differences in the ways they are used in the two countries, but the general principles are the same.

The simplest stopping place, or unstaffed halt, may be identified by the Haltestellentafel, placed at an angle to the track 150 m from the beginning of the platform in each direction, especially when the halt cannot be clearly seen on approach. A Haltepunkttafel is placed to the right of the track at the point where the head of the train is to stop. There may be several such signs for trains of different lengths, generally specified by the number of axles. It may be on a high mast, or low one, and in some cases illuminated as a translucent H with a light behind it in a box. These signs are generally used, not just on a nebenbahn. Sometimes it is even movable, placed by the staff appropriately for trains of different lengths.

A station, which may be staffed and at which trains may cross (meet), is more elaborately signed. The first sign encountered may be the Kreuztafel, which replaces the distant signal. In Germany, the usual Vorsignal sign is now used instead. If necessary, this sign may be accompanied by a yellow light. It is placed at the stopping distance from the next sign, usually 400 m, in view of the lower speeds. The Trapeztafel replaces the arrival signal, and is placed no less than 50 m from the first turnout or other point of restriction. This is a basic signal, and is always present. Typically, a train must stop short of this sign, and wait until called forward into the station. This "kommen" signal may be a white light at the top of the trapeztafel, flashed long-short-long, or a sound on the cornet of the station staff, or by the whistle of a waiting train, and is given when they are ready to receive the train. These days, radio would also be available. Of course, if the station is unstaffed, this cannot be done, so the train must then proceed with caution, prepared to stop short of any danger. Usually, the train proceeds to the H sign, which takes the place of the starting signal, provided there is only one H sign. Some companies have placed a list of trains that are scheduled to cross at that station below the H, in two columns with an X between them.

Some more recent additions are shown in the figure at the left. In place of the H sign, the reflectorized red E on a reflectorized white background may be used to show where a starting signal would be. This is the Fahrwegende (end of route) sign, and there will be one on each track. Like the H sign, it may be high or low. The trapeztafel may be embellished by the Weichenüberwachungssignal, or "turnout monitoring signal," a violet light on a striped, reflectorized red and white background. In Austria, it is a blue light on a red and white striped background, often placed below the trapeztafel at the entrance to a station. This light shows that the points of spring switches (Rückfallweichen) are in their proper positions.

If speeds exceed 50 km/h, the trapeztafel is replaced by a hauptsignal, usually two-armed, and often a light signal. The German symbols for the signals are Ne1 for the trapeztafel, Ne2 for the kreuztafel, Ne5 for the H sign, Ne6 for the haltepunkttafel. Since nebenbahnen may be unfenced and have many pedestrian and vehicle crossings, the whistle and bell are frequently used. The Pfeifetafel, a black P on white background (LP1), is a signal to whistle, while a Läutetafel, a black L on white background (LP2), means ring the bell. The L and P may be side by side on one post (LP3). Two L's, one above the other (LP4), means sound the bell continuously, while an L with an X through it (LP5) means silence the bell. Signs LP3 through LP5 were discontinued after 1972 in Germany.

In Austria, the whistle post, or Pfeifepflock, is now an alternately red and white striped post. From this point to the crossing, the "Achtung" whistle, one long sound, must be made at least three times. Where there are several crossings close together, a group whistle post and an endpost are used. The group whistle post is a red and white striped post topped with a black and white, diagonally striped section. The endpost is white except for a red top. A black screen with four white diamonds on it, one above the other, shows the point at which train-operated crossing signals are activated. Stopping at this point is discouraged. At the beginning of a group of crossings, a white sign with black letters, saying, for example, 3 EK if there are three crossings, is placed. After the last crossing of the group, there is a similar sign with a diagonal red bar across it rising from left to right. The EK-Überwachungssignal (EKÜS) shows a blinking yellow light when the crossing signals are operating properly. At the top of the black and white diagonally striped post is either a constant yellow light or a reflectorized yellow disc. It is placed at the braking distance from the crossing. If there is no EKÜS, a "Schaltstellenpflock" is placed at the point where the crossing signals are activated. This post has black and white stripes, and at the top shows the kilometric location of the crossing.

The Schutzsignal

The Austrian Schutzsignal is a relatively recent type of light signal which evolved from the German Gleissperrsignal (track-blocking signal), that originally was the familiar black box signal described above as a shunting signal, used in a special way. The problem is to create a signal that applies to both train and shunting movements, but is always encountered at low speed within a station. Two typical uses are these: to divide a long track into sections that can accommodate several trains; and to indicate to which track a Gruppenausfahrsignal applies. A Gruppenausfahrsignal is a hauptsignal that applies jointly to a fan of tracks, say the departure tracks of a yard.

The signal was derived from the shunting light signal with its four white lights. To distinguish the schutzsignal, the background was given a white border and the horizontal white lights were replaced by red lights for the stop (Fahrverbot) aspect. This left the clear (Fahrverbot aufgehoben) aspect the same as for the shunting signal. It was thought best to distinguish this aspect clearly from the shunting aspect, so the two lights were arranged vertically instead of diagonally. Finally, the right-hand red light was eliminated as superfluous, leaving the final form of the signal.

German light Gleissperrsignale are similar, but have retained two red lights and the diagonal arrangement of the white lights. From Lorenz, the signal is rectangular, while from Siemens the upper corners are cut off at 45°. Both in Germany and Austria, there are high and low forms, as there were for the box signals.

The Zusatzsignal

A Zusatz is an "addition", a "complement", and Zusatzsignale are added to a main signal to show speeds, routes and other complementary information. One type of Zusatzsignal is the ersatzsignal, which is an "ersatz" or "replacement" for a written order. In Germany, a Form A is permission to pass a main signal at stop that cannot be cleared because of mechanical or electrical difficulties. Since signalling apparatus is "fail-safe," this can happen when it is really all right to pass the signal. Permission can be given by hand signal, by radio, or some similar means, but the ersatzsignal is convenient. When it is displayed, the main signal is extinguished. In Germany, the ersatzsignal Zs1 is a triangle of three white lights suggesting the letter "A", while in Austria it is a simple blinking light at the side of the main signal.

Another zusatzsignal is the Vorsichtssignal, Zs7, which is three yellow lights making a "V". It gives permission to pass a main signal at stop, but to proceed at restricted speed looking out for a train ahead. It is used on S-bahnen and similar operations with short headway and closely-spaced stops. It allows a train to leave a station while the preceding train has not fully cleared the next station, and so avoid coming to a stop. In Austria, it is a blinking red light beside the main signal. Unlike the ersatzsignal, it does not necessarily imply that the main signal is out of order. It is like a "grade" signal in America, which allowed a heavy train to pass a stop-and-proceed signal at restricted speed without stopping, but, of course, the application is entirely different.

The Ersatzsignal and the Vorrücksignal already appeared in the German signal regulations for 1935. These were equilateral triangles of small white lights, showing what looked like an "A" for the Ersatzsignal and a "V" for the Vorrücksignal, which was equivalent to the later Vorsichtssignal. The latter was analogous to the U.S. and British calling-on signal. They were used with mechanical as well as with light signals.

Other Signals

There are several classes of signals that we can only mention in passing here. One type is used in connection with level crossings, from the simple whistle post (which has been mentioned above) to indications that crossing protection is operating properly. Many such signals are simply signs communicating local information to the driver and providing reference points. They may be illuminated, but generally display only one aspect. A shunting limit sign is semicircular, with the legend "HALT für Rangierfahrten (or Verschubfahrten)". An important class is that of speed restriction signs, consisting of the advance warning, the beginning of restriction and the end of restriction. The associated colours are often white, yellow and green. The allowable speed is given by a black figure in tens of km/h in a yellow triangle as a warning. The restricted segment begins with an "A" in a rectangular yellow sign, the end by an "E" on a white (now green) background. Another are signs relating to the electrical contact wire: lower pantograph, raise pantograph, switch out, switch in, and end of wire. These signs are blue and white. At one time, it was important to show the gradient, and signs were used at changes in gradient. Special signs also inform snowplows and flangers when there is interference with their blades, as at level crossings and turnouts. These are arrowheads pointing up or down, originally black, but now white with a black border.

An enduring signal is the modest Haltschiebe or Deckungsscheibe (they are distinguished from each other in the 1935 signal regulations), a rectangular red sign with white border, that may be on a sharp post to be rammed into the ballast, or attached to the bumping post at the end of a track, if used as a Haltscheibe. A red light is displayed by night. Advance warning is given by a yellow disc, or at night by two yellow lights, one on each side of the post and rising to the right. Movable Deckungsschiben may be used to protect movable bridges.

The driver was signalled to start the train by holding up a white disc with a green border on a handle, the Befehlstab. At night, a green light is held up. Brake test lights may be installed at platforms, where the driver and others may see them. These are a series of three lights in a vertical column. One light is a request for application of the brakes. Two lights requests that the brakes be released, and three lights that the brakes are correct--that is, they applied and released on all cars. "Right away" may then be given by extinguishing the lights and showing a circle of green lights.

Another class of signals are the lights, flags and signs displayed on trains for the information of employees on the ground and on other trains. The lights at the front of a train, the Spitzensignal, was for many years two white lamps, one on each side of the buffer. In the 1950's, a third white lamp on the upper part of the smokebox door was added, and is now standard. These lamps never showed the class of the train, as in Britain. A yellow flag on rolling stock meant that it was occupied. A red flag on rolling stock meant that it was not to be moved (in America, a blue flag was used for this purpose). Flags identifying trains carrying munitions or poisonous chemicals are no longer in use. Hand, flag and lamp signals communicate between employees on the ground and those on trains, while drivers use the whistle, bell or horn to communicate information. These signals include detonators (torpedoes) and fusees, as well as horns and pocket whistles. All these signals may be called mobile, and distinguished from the fixed signals that have been our main subject. Radio provides direct communication without the need for physical signals. Communication can also be direct to the hardware by electrical means, bypassing humans, as in train control systems.

The Rangierhalttafel (Austria: Verschubhalttafel) indicates the nearest point that a shunting movement should approach the entrance signal at a station, to be protected from trains approaching the station. The distance "d" must be no less than the required clearance distance in advance of the entrance signal, 200 m on main lines, called the Durchrutschweg. Before a shunting movement can proceed further, control of the block must be acquired. The legend on the signal is no longer required, since the shape of the signal identifies it well enough. The placement of the signal on the DB is shown. The DRG and DR put it on the other side. The diagram shows the Einfahrsignal as a two-arm signal that can display three aspects.


H. J. Obermayer, Taschenbuch der Eisenbahn (Stuttgart: Franckh, 1975).

O. S. Nock, Railway Holiday in Austria (Dawlish: David and Charles, 1965).

H.-J. Spieth, Die Signale der deutschen Eisenbahnen (Düsseldorf: Alba, 1974).

S. Carstens, Signale 1, 2, 3 (Nürnberg: MIBA-Verlag, 2006-7)

C. Hager, Eisenbahn-Sicherungsanlagen in Österreich, Band 2 (Wien: Verlag Popischl, 1994).

ÖBB, Signalvorschrift V2 (Wien: 6 August 1996). The many recent changes in this publication make Austrian practice differ more from German than it has in the past, but the differences are mainly in details.

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Composed by J. B. Calvert
Created 9 June 2004
Last revised 1 April 2007