Belgian Signals

Belgian railway signalling has always been distinctive and innovative, and is still unlike any other


Belgium is 175 mi (280 km) long by 90 mi (144 km) wide, with an area a little less than 12,000 sq. mi. and about 10,000,000 inhabitants. There is a low coastal plain in the west, then a central rolling plain, and the forest of the Ardennes in the east, which is elevated to about 1500 ft. on the average. The River Scheldt in the north flows through Gand and Antwerp to the Atlantic via Holland, while the Meuse flows northward through Liège and also into Holland. The inhabitants are Dutch-speaking Flemings in the north and French-speaking Walloons in the south, who trace their ancestry to the Celtic Belgae of classical times. The language boundary passes from west to east just south of the capital of Bruxelles, which is itself a bilingual region. Belgium is highly industrialized, with the greatest railway density in the world, having about 4300 km of railways in operation. Belgium independence dates from 1830, when it separated from the Netherlands, but the final peace treaty was signed only in 1839. It is a constitutional monarchy. The industrial revolution flourished early in Belgium as well as in England. Iron has been worked with coal in Liège since the 13th century. The important railway centre of Kinkempois is in a suburb of Liège. Railways are not shown to avoid overloading the map. I have not found an accurate railway map yet on the Internet, though several maps showing railways are available. Each railway line in Belgium has an indentifying number. For example, the Quévy-Bruxelles main line is line 96.

The first modern steam railway in Belgium opened 5 May 1835 between Bruxelles(Allée Verte) and Malines (Mechelen), reaching Anvers (Antwerp) the next year. Railways radiating from Malines to Ostende and to Ans (Liège), from Bruxelles to France via Mons, and Mons to Namur, were built by the state. In 1842, the inclined plane from Ans down to the Meuse (Liège-Guillemins), operated by a stationary engine for thirty years afterwards, was constructed. After 1845, private concessions were offered for the construction and operation of railways, and a large number of companies were formed. In the 1880's and later, most of these companies were absorbed into the reconstituted Chemin de Fer de l'Etat Belge (which I shall denote by "Etat" here). At the beginning of the First World War, the Etat operated 4786 km, and four independent companies 275 km. These companies, shown in the map at the right, were the Nord-Belge (associated with the Chemin de Fer du Nord of France), the Chimay (a connection of the Nord's), the Gand-Terneuzen and the Malines-Terneuzen. Terneuzen is on the Scheldt estuary in Holland, at the end of the Gand canal. The Nord operated Charleroi-Erquelinnes (1846), Namur-Liège (1851), Mons-Quévy (1857) and Namur-Givet (1863). Erquelinnes, Quévy and Givet are stations on the French border. In 1926, the Etat became the Société National des Chemins de Fer Belges, or SNCFB, and in 1938 the name was shortened to the present SNCB (in Dutch, NMBS). The SNCB absorbed the Nord in 1940, but the Chimay and the international lines to Holland not until 1948.

Early Belgian railways adopted rotating-vane signals, as did French railways and many others. The red disc was a stop signal, while a red rectangle was an advanced signal, also a stop signal. The Etat signals from the 1909 rule book are shown at the left; they are, of course, much older. Originally at least, a stop was required at the advanced signal before the train could proceed under control, so that a train stopped ahead would be protected. The block system later rendered this unnecessary. In the 1870's, semaphores were introduced on imported interlocked block systems, and the Etat-Belge decided to replace the French-style vanes with semaphores. The Siemens and Halske system was used between Gand and Ostende, with typical German upper-quadrant, two-position semaphores. The Hodgson system from Saxby and Farmer was installed between Bruxelles and Anvers (Antwerp), with typical English wooden lower-quadrant signals. The Etat had already imported a number of Saxby and Farmer semaphores. The Nord-Belge used the signalling arrangements of its parent, the French Chemin de Fer du Nord. This included the disque rouge, the carré, and the Lartigue electro-semaphore. Belgian trains keep to the left, and signals are placed to the left of the track, with semaphore arms pointing away from the track.

Two early Belgian tunnels had signalling significance. The first was the Kumtich tunnel, near Roosbeek and not far from Tirlemont, on the line from Louvain to Liège, built in 1836-7. It was attended by gardes-tunnel at each portal who inspected the tunnel after each train. The tunnel was replaced by a cutting in 1846 because of unstable earth. On the main line from Brussels to Mons, the 544 m Braine-le-Comte tunnel was made in 1841. A second bore, for which the portals had already been built, could not be completed due to unstable earth. This short single-track section in a double-track main line was operated by a pilotman for 90 years. A brick maisonette for the pilotman to live in was constructed at one portal, as pictured on p. 64 of Dieu.

By 1893, the Etat wanted to design its own semaphores, and in that year came out with a two-position lower-quadrant semaphore, the pressed-metal arm descending to 45°. The total length of the arm was 2230 mm. The outer end of the arm was 1850 mm from the axis. It was slightly tapered, from 280 to 320 mm in width. The arm, pivoted inside the lattice mast like a Saxby semaphore, was weighted to assume the horizontal position if free. The spectacle was separate and below the arm, and carried red and green lenses. Green was replacing white as the clear signal at that time. The semaphore could also be arranged for upper-quadrant operation with only minor alterations. The arm was painted red with a white stripe on the front, white with a black stripe on the back. The mast was a steel lattice made of four angles and braces. The finial was cast iron, and rather large and heavy. These masts were durable, and served as well for later arms of different design. After 1893, steel masts were exclusively employed for Belgian signals, the later examples being welded.

The "universal transformable semaphore with multiple arms" appeared in 1904, and set the standard for Belgian semaphores. The arms were two-position, and upper quadrant, clearing to 45°. The construction was modular, and used standard parts, so that everything did not have to be specially designed for each new installation. The arms were 2000 mm long, with the axis 390 mm from one end. The arms were parallel, in front of the mast, with a width of 300 mm. The vertical distance between arms was 2190 mm. The lamps were behind the arms, and shone through apertures in the arms. Some arms had two roundels side by side for the display of double lights. The varieties of arms used is shown in the figure. Arm (1) is the standard stop arm. Arm (2) is called "oriflamme," which is the name of this shape in French, from its similarity to the banner of St. Denis of that name, a flag with a notched fly. This shape of arm indicated that the route it governed could be negotiated at full line speed. It was generally one of the arms in a directional signal, in which the highest arm governed the route furthest to the left, and the lowest arm the route furthest to the right, with the intermediate arms taking their place in the sequence. Only one oriflamme arm was used, if any, and it could be any one of the arms, not necessarily the top one. By night, it displayed two green lights, while a normal stop arm displayed only one. Later, numbers displayed near an arm indicated the route. Arm (3) is called a "repeating arm" and was the distant signal familiar from British practice. The arrowhead termination was characteristically Belgian. It showed the position of the stop arm on the next signal ahead. When this arm was horizontal, so was the stop arm ahead. It was arranged that if the stop arm above it was at stop, the distant arm could not be inclined.

Arm (4) is a shunting arm. When inclined, it allows an engine to shunt ahead, but not proceed into a block. The movement must be made at restricted speed, since the way is not guaranteed to be clear, nor the route properly set. The lights displayed for the night aspects are smaller in diameter than the main lights. Arm (5) governs shunting operations, or entry into other than main tracks. Arm (6), the "bow tie," authorizes backup movements against the current of traffic, and is similar to arms used for the same purpose on the London and South Western Railway at the time. In fact, the finial of the 1904 mast was very similar to the design used on the L&SWR.

These signals were also used on the "chandeliers" that showed routes with arms on masts (dolls) side by side, in the English manner. The chandelier made the oriflamme arm unnecessary, since the importance of the routes was shown by the heights of the arms. Chandeliers might combine stop and distant arms as required. Chandeliers with distant arms only ("splitting distants") were also used to give an advanced indication of route and speed. All these features were distinctly Belgian, derived from British practice, and not similar at all to French practice, where nothing like this was ever done. A signal governing a junction that did not provide any directional advice was provided by a "Y" plate on the mast.

The famous signal engineer for the Etat, L. P. A. Weissenbruch, devised a distinctive code of semaphore signal aspects using three-position arms in 1919, many examples of which survived until recently. This was a good time for a revision, since much signalling had been damaged by the war, and renewals were necessary. The Belgian code was quite different from German and French practices. Route signalling was used at junctions, with one arm per route on separate dolls, as in England. Equilateral triangles at the bottom of each doll, point down, might show a figure giving the speed in 10's of km/h, in black on yellow. Semaphore arms were three-position, as in America, but there were now four basic aspects that could be given by two arms. The Stop and Proceed aspects were familiar, displayed at night by red and green lights. The Caution aspect, yellow by night, warned that the next signal was at Stop. Unless preceded by Attention, the full stopping distance was available. The Attention aspect warned of a divergence ahead, restricted stopping distance (from a Caution in advance), or end of track. As in the German Langsamfahrt, yellow and green lights were displayed simultaneously by night, but side by side, not vertically. Shunting arms were painted violet, and a violet light was used in place of red when the arm was horizontal, so that a driver would not have to pass a red light when authorized to proceed to the next station. Double wires were used to operate three-position signals.

The arms used for three-position signalling are shown at the left. The 1919 arms rotated about an axis not far from their centres, like British "somersault" signals, and when vertical lay alongside the mast in the same way. They were linked to separate spectacles with three lenses (French: trinocle). The night aspects are not clearly shown in the diagram. The distant arm displayed yellow, yellow and green, and green. The double light was produced by a mirror. When not desired, this (green) light was obscured by a screen. Sometimes the black chevron on the distant arm was replaced by a straight black stripe (this seems to have been the case for the back of the arm). The violet shunting arms were mostly restricted to horizontal and 45° for shunting within prescribed limits. Some could be made vertical, however, and this authorized a movement into a siding (mouvement de garage).

Stop and distant arms could be on the same mast (signal combiné), the stop arm above and the distant arm below. This signal displayed four aspects, passage, attention, avertissement and arrêt. The distant arm was painted yellow, with a black chevron on the arrowhead on the front, and a straight black line on the back. The figure shows how the 1919 pattern signal lamp could be arranged to display yellow, yellow and green side by side, and green for the three positions. The green light was produced by reflection. These night aspects were preserved in the later light signals. The stop arm could display red, yellow and green. When at passage, both arms were in the 90° position aligned with the mast. When the stop arm was vertical, the distant arm could not be horizontal, though Dieu shows a photo where this contradictory aspect was nonetheless displayed.

The stop and distant arms could also be used on separate masts. When this was done, the aspects of the stop arm were: arrêt, passage, signal suivant à l'arrêt, and passage, signal suivant au passage, when at horizontal, 45° and vertical, respectively. In American terminology, these are stop, approach and proceed. The distant arm alone displayed passage à l'avertisseur. When horizontal, it indicated that the next signal was at stop. At 45°, it indicated that if it preceded two stop signals less than 800 m apart, the first was at passage, but the second was at stop; or, if it preceded a chandelier with unequal dolls, that a diverging route was signalled. When vertical, it indicated that any stop signals ahead were at passage, or if preceding a chandelier, that a route was signalled that could be taken at full line speed. The corresponding night aspects were yellow, yellow and green, and green.

At the left are shown mechanical low signals, called "simplified equipment." The violet disc applies to shunting movements only, while the red rectangle applies to all movements. The red rectangle could be high as well, with the same significance. When "off" they display a yellow light. Corresponding light signals will be mentioned below.

The 1931 arms have the spectacle incorporated in the arm, as in an American three-position semaphore. The roundels are 180 mm in diameter. When these arms are used for two-position signalling, the modifications shown are made. 1919-style distant arms had the black circle in the middle of the arm when used in two-position signalling. These arms clear only to 45° and present the usual three night aspects (red over yellow, green over yellow and green over green). The three-position signalling gave an additional aspect, "attention," when the distant arm was at 45°, showing by night yellow and green side by side. This was used like the "approach medium" aspect in American signalling to indicate that there was a speed limitation ahead. This system was the basis for the aspects of colour-light signals, introduced in 1932, 1935 and 1947.

After the destruction consequent to World War II, renewal of much Belgian signalling was necessary. Since colour-light signals are only about half as expensive as mechanical signals, there was a great incentive to replace semaphore signals with them. These signaux lumineux are an excellent example of Belgian rationality, borrowing from past experience while introducing new elements to meet new conditions. The aspects are shown at the right. The basic high signal has five lights, two green, two yellow and one red. Any signal has only the lights installed that are required. The lowest light may be a smaller white light for use as a shunting signal. There is another type of high signal with only three lights: green, red and white from the top. This signal displays only stop, proceed and shunt ahead. It looks like a normal three-aspect colour light signal. Belgian light signals offer pure speed signalling; route information is not presented. Speeds are presented by illuminated figures or by signs on the signals.

The names given to the aspects suggest the indications to one familiar with American practice, but are not exactly those used by the Belgians. Stop and Proceed are quite clear. There is an additional double-green aspect allowing 160 km/h (100 mph) operation on lines signalled for 140 km/h otherwise. It is always followed by another double green or a single-green Proceed, so that additional braking distance is provided. There are three Approach aspects. Two yellows is the ordinary Approach: proceed prepared to stop at the next signal. A green and a yellow in a horizontal alignment means approach next signal at slow speed, 40 km/h unless otherwise indicated. Illuminated speed indicators may change the speed; a Proceed at 40 km/h is illustrated, acting like an American Slow Clear. The digit gives the permissible speed in units of 10 km/h. The aspect called Advance Approach is often used where full braking distance is not provided, and can mean essentially stop at the second signal. Some signals are normal stop signals, others are warning (advance) signals that do not show Stop. These signal types are illustrated at the left. Note that only the identification plate distinguishes them. The avertisseur can also display the green-yellow approach aspects, but only the simple case is shown here. The two yellows is just Approach; it should not be confused with the British double yellow (which in Belgium is green over yellow).

As in German practice, two kinds of movements are distinguished: train movements and shunting movements. Shunting movements always proceed at restricted speed (marche à vue, maximum 40 km/h), and within definite limits. To allow shunting movements but not train movements, the white light is illuminated as shown. A movement passing a high signal at Proceed automatically is classed as a train movment, while a movement proceeding on the shunt ahead aspect is classed as a shunting movement. High signals can change the type of a movement. Shunting movements must conform to the indications of the dwarf signals; these signals do not alter the type of movement, and do not apply to train movements. The simplified signals shown at the right are like the shunting signals, except that they display red instead of violet, and apply to both kinds of movements. They do not change the type of movement. They are like the German Sperrsignale, and can be used in the same way to select one movement from a group that is governed by a common high signal, or to subdivide a track segment.

Many important main lines are now signalled for movements in both directions, and special light signals are provided for movements on the right-hand track. These signals are mirror images of the usual signals, and are placed on the right of the track instead of on the left. The aspects are the same, except that the lights are clignotants, or blinking. One must distinguish this from movements against the current of traffic, which is quite another thing, and always extraordinary. Crossover movements are preceded by the white chevron at the top of the signal. This chevron, of course, is never shown above a signal at Stop. In the same place as the chevron may be an illuminated "U" for a track of limited length, or a straight horizontal line indicating very short braking distance. These have nothing necessarily to do with movements on the right-hand track. An illuminated "X" probably signifies that the route signalled is to a track that ends ahead, as at a terminal station, but may also be an early version of the chevron. The number plate for contre-voie signals has short radial lines at the corners.

Illuminated signal repeaters are shown at the left. They are used when the main signal cannot be sighted from the usual distance (about 300 m) or is obscured at certain points, due to structures or curvature. The diagonal line indicates that the signal is clear for no speed restriction. In all other cases, the horizontal line is displayed.

Turnout point indicators are shown at the right, and specifically show the position of the points. They were introduced only around 1925, and were adapted from German examples. The aspects should be self-explanatory. The arrows or bars are translucent, and are illuminated from within. They rotate by 90° around a vertical axis between their two positions. Earlier indicators were often like American switch targets.

Standard modern fixed speed limit signs are shown at the left. As usual, the numbers indicate speed in units of 10 km/h. They may be mounted on signal masts, or on their own supports. The green triangle means resume normal line speed, while the yellow triangle bordered in green means resume a higher speed, but less than the normal line speed. When temporary, the advance warning is accompanied by two flashing yellow lights, one on each side. Two black dots are placed at the top corners of the restrictive signs, and two white dots at the bottom corners of the resume speed sign in this case. There are also mobile signals used where necessary. A red flag or rectangle (or a burning red fusee) is a signal to stop; a yellow flag or rectangle to proceed not exceeding 20 km/h (at night two flashing yellow lights in addition). A green flag indicates the end of the restriction.

The Indicateur Operations Terminées is shown at the right. This is a repeating animation and will show how the signal actually appears. It is a platform signal to indicate to the driver that the train is ready to leave. The red light comes on for 7 seconds as a warning, then the six white lights are displayed, provided the signal for leaving the platform is off. This signal is popularly called "la marguerite" (the daisy).

A practice strange to American and British observers is the use of acoustic signals in shunting. Everywhere, the driver operates the locomotive as directed by a shunter on the ground or riding on a step. In America and Britain, these directions are given by hand signals or, in recent times, by radio. In Belgium, and elsewhere on the continent, sounds produced by a whistle or horn are often employed. They can be used when the shunter is not in the direct line of sight of the driver, as in making couplings, or on the wrong side. They can be given by a pocket whistle, but in Belgium the curved horn was the preferred instrument. Two sounds, - -, was the signal to move forward (chimney first, in steam days) and three sounds, - - - , to move backwards. One long sound, --, meant to slow, and three sounds repeated three times, ... ... ..., was the signal to stop. Historically, horns had other uses, such as starting a train (the stationmaster used his pocket whistle, and the head guard sounded his horn). Horns, usually straight and in recent times blown by compressed air, were used to warn crews working on the track of the approach of a train.

A waving black flag can appear on a sign on a signal mast. This indicates that light maintenance equipment can pass the signal at stop on the waving of a yellow flag from a window of the signalbox concerned without further formalities. This is sometimes mentioned as a peculiarity, the use of a black flag in signalling. The abbreviations HKV and HKM refer to passenger and freight trains, respectively. The "HK" may stand for the Dutch hakenkonvooi. Belgian pantograph signals are identical to those in France and Germany.

References

M. G. Tweedie and T. S. Lascelles, Modern Railway Signalling (London: Blackie and Son, 1925), pp. 53-60.

J. Chabottaux Histoire de la Signalisation Ferroviaire in Belgique, Tome I (Bruxelles: P.F.T. T.S.P., 1996). Deals with hand signals. Includes some Belgian railway history. This book and the following one, in the unfortunate French tradition, have no indexes, which makes looking up specific illustrations bothersome.

B. Dieu, Histoire de la Signalisation Ferroviaire in Belgique, Tome II (Bruxelles: P.F.T. T.S.P., 2002). Deals with fixed signals up to, but not including, light signals. This work is very profusely illustrated.

__________, Aperçu de la Signalisation Ferroviaire Belge (Bruxelles: Edition P.F.T. and Jocadis, 2003).

R. Lemon, An Introduction to Belgian Signalling (Signalling Record Society Signalling Paper No. 14, 1996). Rests heavily on the preceding reference, but is in English.


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Prepared by J. B. Calvert
Created 5 March 2000
Last revised 6 July 2004