Signaux Électriques à Cloches


For many years, single-track branch lines of moderate traffic in France were protected by signal gongs, which furnished a simple but effective safety system, cheaper than the block system. I'll speak of gongs, not bells, to emphasize that they were not small electric bells. Similar systems were also used in Austria-Hungary, Germany and other European countries, but not in Britain or the United States, where nothing even remotely similar was ever used. Bells may have been used there in railway signalling, but not in this way. In Britain, the block system was universal, and in America employees along the line were too scarce. The present paper is intended to give an appreciation of the French system for English-speaking students of railways. The author is not an expert in French railway operation, but is an interested student, and will appreciate any corrections or amplifications to this material.

These bells were called "Austrian bells" in France because they were widely used in Austria-Hungary and northern Italy, or alternatively "Leopolder bells," from their inventor. In Belgium, they were called grosses sonneries de route. In Prussia, bells were introduced from Halle to Weissenfels in 1846 by August Mons of the Thuringian Railways, who had the bells made by F. Leonhardt of Berlin, and the next year on the Buckau-Magdeburg and Köln-Minden lines. They were first used in 1854 on the Semmering-Bahn (Südbahn), and later on the Westbahn, the Nordbahn, and other lines radiating from Vienna. The Chemins de Fer du Nord Belges used Siemens and Halske bells between Namur and Givet in 1862, and the Etat Belge introduced them in 1874 on the Leuze-La Pinte and Denderleeuw-Courtrai lines, in 1875 on Landen-Ciney, 69.5 km, and between 1872 and 1879 on Chênée-Verviers(Ouest), 33.4 km. They first were introduced to France in 1875 by the PLM, which developed the system and eventually used it on more than 800 km of line, initially using Leopolder bells. In the second half of 1878, bells were installed between Alais and Langeac, with about one bell per kilometre. Each intermediate station had two bells, one for each direction. Tests made on this line were very satisfactory. Bells prevented an accident on 1 November 1878 when a freight train was "doubling" a hill between Aix-les-Bains and Chambéry near midnight. When the engine returned to get the rear part, it had vanished, and run away down the line, where it came to rest. The conducteur-chef ran to the nearest bell station and raised the alarm, which was successful in preventing an express from leaving Aix-les-Bains and colliding at speed with the wagons. On 7 June 1879, on the Paris-Montargis line a light engine was dispatched from Malesherbes, forgetting an opposing freight meant to meet it there. When it was noticed by the bells that opposing trains were in the same section, the alarm was raised. A crossing watchman flagged the light engine unsuccessfully, but the freight was held so that the light engine was stopped by signals at La Brosse. In spite of two errors, a collision was avoided. Electric bells were also used by the Paris-Orleans, and Ouest companies. The Ètat operated the single-track lines radiating from La Roche-sur-Yon to Les Sables d'Olonne, Velluire and Nantes (the back way through the Marais) in the Vendée with bells from 15 November 1883. The Ouest used bells from Beuzeville to Fécamp, Pointoise to Gournay-Ferrières, Pont l'Evéque to Honfleur, and on the line from Saint-Pierre-du-Vouvray from 25 May 1884. Ministerial circulars of 1880, 1882 and 1898 prescribed the installation of bells on single lines as a safety measure.

On these lines, trains were dispatched from gares by a chef de service, or stationmaster, according to published schedules. The stationmaster was in telegraphic contact with the stationmasters on either side of him for consultation relative to the movement of trains. Arrangements were made between stationmasters to alter the schedule meeting points of trains to compensate for delays and other irregularities. These arrangments were made under the regulations of the Règlement Générale d'Exploitation.

At first, stations were protected only by "GARE" signs that commanded trains to be brought under control before reaching a point marked by a downward-pointing chevron sign. Two trains meeting were not permitted to enter the station simultaneously. One would be held outside the station until the other had entered and stopped. Later, disques rouges provided much better protection, even for a train waiting to enter. These were usually automatically displayed by a pédale Aubine, but were restored by hand. The disque rouge allowed a train to run through a station at speed. The bells were in addition to any such measures.

Each train was under the command of a conducteur-chef. The chef de service signalled to the conducteur-chef when the train should depart, who in turn signalled the mécanicien to start the train. Before the chef de service could start the train, he personally gave the gong signal to the next gare in the direction the train was proceeding. In France, the directions are called pair ("even", terminus to destination, from Paris) and impair ("odd") as they are "up" and "down" in England, or in a compass direction in the United States.

The signal to start a train in the sens pair was dong dong---dong dong---dong dong. Each "dong" was separated from the other by 2 seconds, and the pairs of dongs by 5-6 seconds. For the sens impair, the signal was dong dong dong---dong dong dong---dong dong dong. These were signals "2" and "1" respectively, and were the normal signals heard. It was expressly forbidden to repeat these signals. One signal, one train. All signals sent and received were noted in a journal, with the accompanying times. Only the chef de service could send these signals.

The gongs were struck by a hammer driven by a falling weight, released electrically. All the power was gravitational, the electricity serving only to operate the clockwork escapement. Each interruption of the current meant one sound of the gong. Gongs were placed at all necessary points between the gares--at stations and halts where trains stopped, at level crossings guarded by gatekeepers, where guetteurs (lookouts), aiguilleurs (switchtenders), and poseurs (platelayers) were stationed, perhaps in their guérites (shelters). There were gongs at postes d'aiguilleurs (switchtender's huts), maisons de gardes (police stations) and postes de signaux (signal boxes). Crossing keepers at the passages à niveau were not required to keep their gates down, but had to watch out carefully for the train. There was, of course, a gong at each gare, and also at remote points nearby. It was intended that no part of the line would be out of earshot of a gong. People residing close to the line probably found this annoying. Note also that the driving weight in each gong had to be wound up regularly by les agents de voie, usually before the first train of the day. The État gongs could give 225-234 sounds on one winding. There was a considerable variety of bells produced by different manufacturers. The original Leopolder bells were mounted on the wall of the station, with the works inside. Illustrated here is the later more common pillar variety, typical of Siemens; they were called à pigeonnier, "dovecots", from their resemblance to a bird house on a pillar. Some had a pillar, as shown, while others had a cylindrical housing (à tourelle). There could be more than one bell, to distinguish different directions. Leopolder bells had a wooden enclosure for the weights and mechanism inside the building, connected by a wire to the external bell. On the Nord, the Siemens pigeonniers also had a yellow lattice arm that became horizontal when a train was announced. The arm was restored by hand. Chabottaux shows several types, one of which has been preserved on a tourist railway.

All the gongs were connected in series, and a continuous current normally was present in the Leopolder system. Siemens gong systems were operated by intermittent currents from magnetos instead of by a closed circuit. This made it possible to interrupt the current, or crank the magneto, and cause the gong to sound, from any point along the line. The battery was a zinc and copper cell like the gravity cell, but arranged for minimum maintenance, called the Meidinger cell, similar to the French Callaud cell. An economy arrangment was devised in which a small Meidinger battery served to provide the steady current, but when the circuit was interrupted a stronger (intermittent) Leclanché battery was connected to release the mechanism.

It was an emergency when a car or cars got loose and ran away; they were said to be en dérive, and every means was taken to stop the runaway. If they were running away in the impair direction, the signal was oooo--ooo--oooo--ooo--oooo--ooo, where o = dong. In the pair direction oooo--oo--oooo--oo--oooo--oo. These were signals "3" and "4" respectively. Employees were warned not to try to stop a train if the runaway was behind it, but to pile on sand to slow the runaway if it was not. If the loose vehicles carried no passengers or employees, it was all right to divert them onto a side track and let them collide with standing equipment if nothing else was possible. A train in front of a runaway had to unload all its passengers, while the engine pulled 200 metres ahead, after which its crew left the area. Brakes were to be screwed down hard on the train and the engine. Of course, a runaway could stop on the line, and an engine would have to be sent to retrieve it.

In case there was a collision, or the line was obstructed or otherwise rendered impassable, The General Stop, (arrêt général), signal "5", was sent, oooooooooooooooooooooooooooooo, at least 30 dongs, by anyone detecting the danger. The gongs were usually rung by buttons at the gares, but at most of the other locations, there were buttons under seal. When the seal was broken, the button could be pressed. A written report was prepared and sent up when this happened, so the service de la voie could replace the seal. When this signal was heard, all fixed signals were placed at Stop, and people went out with flags, lamps and pétards (torpedoes) to stop all trains and engines as soon as possible. Stationmasters on each side conferred on the telegraph. The first train over the line after the emergency had to run with caution.

If a signal was sent in error--for example, if a train was signalled but was to be delayed more than 15 minutes, signal "6" was sent to annul it. This signal was ooooo--o--ooooo--o--ooooo--o, as usual a distinctive grouping sent three times. When a signal maintainer merely wanted to test the gongs, he could send up to four single dongs, separated by at least 15 seconds. The signal could not be repeated until at least two minutes had elapsed. Any signal once begun had to be continued, even if the sender's gong misbehaved. A strange signal coming in would require a telegraphic message for clarification.

Where night trains ran, but some gares were closed by night, there was a commutator switch to connect the gong wires through, in the same way as the telegraph wires. If the night watchman heard any of the emergency signals, he was instructed to wake the Chef de gare, as well as putting the fixed signals to Stop if signal "5" was sent.

These gongs were a supplementary, not a primary, safety device. In cases of confusion, they prevented opposing trains from occupying the same track, and in any emergency trains could be stopped by anyone along the line until it was cleared up. Often, the bells were retained when a line was doubled for the convenience of announcing the arrival of trains. Many period photographs of stations show the bells on the platforms. Most had disappeared by the 1930's, but a few survived through the Second World War. It would be pleasant to see (hear) a historic film or TV show use these bells for atmosphere.

The bells were also widely used in Germany from 1846, where they replaced the two-arm optical telegraphs and gave the same messages. They were used on all lines with line speeds of 40 km/h or greater. Each line was assigned a certain number of strokes, so that the different bells at any location could be distinguished. There were four signals. The assigned number of strokes meant a train was coming from A to B (Abläufsignal 1). A doubled number of strokes indicated a train from B to A (Abläaufsignal 2). A triple number of strokes cancelled one of the preceding signals given in error, or indicated that there was no train on the line (Ruhesignal). In case of danger, six repetitions demanded an instant halt to all movements (Gefahrsignal), communicated to moving trains by hand signals. The bell signals were designated Lt1 to Lt4, in the order given. The most widespread bell type was the Mantelbude, which became the common name of the cylindrical apparatus, placed outdoors beside the tracks. The bells were taken out of service in 1965, and were finally dropped from the signal regulations in 1972.

References

J. Chabottaux, Histoire de la Signalisation Ferroviaire en Belgique, Tome I (Bruxelles: Edition P. F. T., 1996), pp. 67-76.

D. Wurmser, Signaux Méchaniques (Grenoble: Presses & Editions Ferroviaires, 2007). pp. 82, 106-109. Excellent illustrations.

Through the kindness of M. J.-P. Gruffaz of Ploemeur, France, the following references were made available to me:

Règlement pour l'usage Des Signaux électriques à cloches sur les lignes à voie unique (Paris: PLM, 1909)

M. de Castelnau, Annales des Mines, 7th series, 1880, pp. 509-530. "Notice sur les Signaux Électriques designée sous le nom de 'Cloches Autrichiennes'".

M. Bouvet, La Technique Moderne, Vol. XVI, No. 18, pp. 598-600 (1924).

S. Carstens, Signale 1 (Nürnberg: MIBA-Verlag, 2006), pp. 14f, 17, 20, 93. Signale 3, p. 140, pp. 142-143.


Return to Rail Index

Composed by J. B. Calvert
Created 1 April 2002
Last revised 15 March 2008