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По умолчанию Introduction to the Semaphore

Introduction to the Semaphore


Background, Terminology & Characteristics


The semaphore signal, the nearly ubiquitous signal of a former era, is no longer expanding and is, in fact, very much obsolescent. But it continues to be important due to the numbers in operation, and because the semaphore has shaped the message systems of most other signals; this is true not only of position-light and color-position light signals but of all fully-lighted signals.

There is no one term that describes all of those signals which display day messages by means of an arm and night messages by colored lights. The term "semaphore" is in use for English speaking nations and many Romance-language nations; it is also employed by other systems including Sweden. But the term is not employed in German-speaking nations. Those systems, as well as German-influenced systems such as that of Poland, use the "formsignal" (DB 1981). For this study the term "semaphore" will be employed as a general term but keeping in mind that differences between Germanic formsignals and those of other nations exist.

A connecting link in terminology and in signals is found in Sweden where a signal akin in design to the Germanic is in use but under the title of "semaphor" (SJ 1979, 21). A further connecting link is the French edition of SBB's signal code (SBB Les Signaux 1981) which employs semaphore not form signal. It may be further noted that the term formsignal encompasses all less than fully-lighted signals for those systems using that term while semaphore encompasses only specifically semaphore signals and not other partially-lighted signals. In one "school" of signals there is no single term for all less than fully-lighted signals while in a second "school" there is no separate term for semaphore-type signals. A literal term for arm signals is that of armsein in the Netherlands; arm has the meaning it has in English, and sein represents sign (Op de Rails, 1985).

Characteristics of the semaphore (beyond the core elements of arms and lamps) includes the relationship of arm to lamp, whether upper quadrant (UQ) or lower quadrant (LQ), and whether left-handed or right-handed. In much of continental Europe signals are mounted on the right side of the signal mast (though in Spain and portions of Scandinavia they are mounted on the left) . U.S. practice places the arm generally on the right side. UK and derivative/influenced systems position place the arm on the left side of. the mast. Asian systems, including those of Japan and Indonesia are on the left (see respective codes: DB, RENFE, AAR, SJ, JNR, PKNA). Quadrant refers to the direction of the signal arm. If the arm moves from the mid-point upwards it is an upper quadrant signal; if it moves downward then lower quadrant. A three-position upper-quadrant has three movements: horizontal (halt), three-quarters upward (caution), and vertical (proceed). Two-position signals contain halt and proceed indications only. Three-position LQ signals are very rare (Signals & Signal Symbols 1911, 15) .

Locations of LQ and UQ signals display diverse patterns. UQ are quite common on the continent of Europe; the Netherlands by contrasts includes notable numbers of both UQ and LQ forms. In areas influenced by UK and US there are often both forms; ratio of UQ to LQ is probably greater in US than in UK. LQ have been declining probably since the early twentieth century; UQ was expanding in usage for a portion of the century but they too are becoming a less common signal. UK began a limited usage of UQ after World War I; the LQ form finds a measure of usage even now (UK K&W 1963, 12). The most mixed picture is probably in Australia: Western Australia includes somersault LQ as well as US-style UQ. ANR employs mostly three-position UQ though some LQ remain; New South Wales and Victoria include both forms; Queenslands is a LQ strong-hold (see respective signal codes: AAR, UK, WAGR, ANR, NSWR, VR-A, QR; see also SAR, various South American codes).

South Africa follows a UQ pattern of two-position signals (SAR 1936, also newer publications). Indonesia utilizes both LQ and UQ though the latter predominates (PNKA 1971) . Turkey emulates German practice for older signals (TCDD 1987); this is also true of Thailand. The Indian sub-continent, New Zealand, Ireland, various South American systems are influenced by U.K. The Philippines also employes U.K. style patterns (ROSTEJU 1954, 21-22). Japan, despite sophisticated systems, retains some LQ signals (see respective signal codes).

Models of the Semaphore: National, Regional, and Technical Considerations


For much of the English-speaking world -as well as portions of the Third World - the semaphore conjures up a distinctive image: an image of a one/two/three-arm brightly painted blade in hues of red or yellow, punctuated by a distinctive-shaped end and fastened to a spectacle of red, green and possibly yellow. Despite this image, the semaphore is not a monolithic object. The model so described is only one of several semaphores in use. This particular form, what may be termed the Anglo-American model, exhibits message capabilities determined not only by the position of the arm, but by the color of the blade as well, and by the shape of the end of the blade. The day portion of the signal (blade) and the night portion (the spectacle) are an integral unit (the tumble-arm or balanced-arm model is not fully integrated but the parts are integrated through linkage; see U.K. K&W 1963, 8-9) .

Color is an important "ingredient" for the Anglo-American semaphore. It may be wondered if color is essential since is the practice of many railways to paint all blades (U.K.: arms) of the same shape a single color. For example, U.K. distant signals display a swallow-tail (U.S.: fish-tail) and painted yellow with black trim while home signals (with blunt ends) are red with white trim. The blades would be distinctive even if identified only by shape (and the reverse could be true: one shape but different colors). It is possible that this "double-identification system" aids quick recognition of a signal. In the case of New South Wales, all semaphore blades are painted red even though different shapes are in use (NSW 1952). NSW practice may support the notion that color patterns are a useful dimension though not essential.

U.K. semaphores (and these are also found in EFEA, ENF, IR, PR, ROSTEJU [for Burma], SAR, etc.) have a "true" rectangle shape while the U.S. form is slightly tapered (AAR 1948, 46). The source of a system's semaphores can be frequently determined by the shape of the semaphore blade. In Australia - where both U.K. and U.S. forms are in use - the source of a semaphore's origin can be determined by visual appearance. Whether a signal is left-hand or right-hand is a second mark of origins since U.K. has left- hand models and the U.S. has right-hand versions. U.K. seemingly lacks a term to describe the assembled semaphore mechanism since it simply refers to arm and spectacle while the US terminology reserves arm for the assembly which is made up of blade and spectacle (AAR 1948, 38, 42/ U.K. K&W 1963, 14).

The previously mentioned tumble-arm (or balanced arm) signal is a U.K. product. It was developed in response to an older form of semaphore that, on occasion, gave an erroneous clear indication during times of snow or other problems. The somersault was so designed that its normal position was one of halt even in times of snow or broken control wires (Blythe 1951, 55). The blade and spectacle are not separate units, as is so often the case on the continent of Europe. The two components are linked by a rod so that movement of one requires the movement of the other. Shape, color and position characteristics are those of UK practice. The signal, though minor now in UK, has remained a major signal for Western Australia and New Zealand (WAGR 1974; VR-A; NZR 1985).

A modified version of the integrated semaphore is found in Argentina and in Uruguay. The arm is standard but the spectacle component is of a variant design. The lenses for this unit may be smaller than with standard forms (EFEA 1958, HOff; FE 77-78; see Chapter 29B2 for an illustration).

Dutch semaphores (seinpaals or armseins) bear a partial resemblance to Anglo-American and European models. All of the Dutch semaphores have the arm and spectacle joined together which parallels U.K. and U.S. practice (Op de Rails 1985a TIRSP). However, these signals have the rounded ends associated with German or Central European semaphores. Other Dutch semaphores have square ends, and arrow-shaft shaped ends. Both UQ and LQ signals are in use and in some instances they form a single installation.

The type of formsignal associated with German practice is an important form but it is only one of several forms in use. There are differences not only between nations but also between regions. For example, some southern European nations employ semaphores bearing some resemblance to U.S. and U.K. models. West-central Europe is populated with a variegated pattern; the Netherlands, France, and Belgium each have developed singular forms. Finland and Sweden have also produced variations reflecting their railways and societies. Much of central and eastern Europe conforms to the Germanic pattern. A key characteristic of many of these signals is the separation of arm and lens; this is true even of some signals that bear a visual resemblance to the U.K. and U.S. models (see RENFE for an example of this phenomenon).

The Germanic form frequently is found only in one pattern: an elongated rectangular arm ending in a disc. The signal is often painted white with a red border. The signals may be either UQ or LQ and may have one or two arms. This signal as found in DB, DR, OBB, PKP and other systems separate arm and lamp units. The Finish and Swedish form have an opening in the arm since the signal, in the halt position, is centered over the red portion of the lamp. This practice is also followed in Yugoslavia and Hungary though in those cases the form has a squared-off end and a half-spherical inner end (where the arm is attached to the remainder of the mechanism). The Yugoslav arm has two red stripes equidistant from the edges of the arm in contrast to Germanic form where a single stripe follows the outline of the arm (see signal codes of the systems included in this paragraph).

The form signal of Switzerland is of a slightly different shape and color pattern though it remains within the European formsignal tradition (SBB lOff). Turkey and Indonesia employ form signals that stem from German and Netherlands practices respectively (TCDD among other sources; PNKA).


Belgium has a variety of semaphore forms of which most are of distinctive - and even singular - design. The foundations of Belgium practice are based on destruction of older signals in World War I (see Nock 1962, 79ff). Many other European nations continued older patterns of signals until the destruction of World War II led to contemporary color-light signals. But Belgium's changes occurred when semaphore forms were still very significant and their first new system continued the semaphore pattern. Patterns include standard rectangular forms with square-end and disc-end forms (SNCB 1967, 88, 96 122). They also include two forms with an arrow shaft end; one of rectangular form and one with oval shape mid-length along the arm of the semaphore. The final form is rectangular with square-end but with a partially oval lower edge for the inner part of the arm.

Other distinctive forms include the lattice-work semaphore (CZD) and the double-arm lattice-work semaphore (SBB). What might be termed a "propeller arm" semaphore is employed in DB and DR for specialized purposes (DB 1981, 50-51; DR 1971, 109-111) .


Редакторы: Admin
Создано Admin, 09.02.2012 в 15:37
Последнее редактирование Admin, 09.02.2012 в 15:37
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