Signal Boards
Terminology, Types and Locations
The reader may recall from International Marine Aids to Navigation (Volume I, Parts С & D, 2nd. edition) that some forms of daybeacons are only found in a few places and are important for only a few nations. Yet that study could not leave out an important marking even if few systems included it: a transportation marking can be important even if far from global in scope. Railway signal boards represent an analogy to those daybeacons: they are not global and they are important to only selected systems. Yet a study purporting to be international can not exclude them.
Signal boards are found mostly in Europe and date back to the nineteenth century. They are a separate form of signal that stands apart from semaphore as well as from all-lighted signals. There may be a muted resonance with unlighted targets of North America and several other systems. Signal boards are varied in appearance and follow mostly geometric shapes: triangles, discs, squares and diamonds. Signal boards are rarely fixed (that is, the signal apparatus), a somewhat substantial number are hinged, and more are revolving in nature. There is no extant term to describe these signals; "signal board" is described below and offered as a possible appellation for these safety aids.
In Germanic nations, and nations influenced by German practice, the term "Form Signal" is applied to all less-than-fully-lighted signals. But that fails to differentiate between signal boards, semaphores, points/switch indicators, and so forth. The situation, in varying degrees, is true in other European nations as well. In English-speaking nations it is frequently the practice to have a specific name for each signal but there are no over-arching titles (unless one can include words such as unlighted or partially-lighted as titles).
The term "Signal Board" appears to have potential for describing these signals. Signal board is found in various dictionaries though with a different meaning. The Oxford English Dictionary while not including signal board does include sign board which is a board for mounting a sign or is a sign in itself (OED, Vol. IX, 36 ). Both Random House and Webster's Third International dictionaries include signal board but not in the sense proposed here (RH 1966, 1326; WTID 1961, 2115). Signal board in this sense may refer to a board in an elevator containing a list of signal indications, or it may refer to a list of elctronic impulses for some purpose or other. Neither RH or WTID include signal board as a signal in itself.
Since the term signal board is accepted as either as a sign or a foundation for a sign it seems plausible that signal board represents an analogous situation for signals consisting of a board or mounted on a board. What alternative terms to signal board are there? Other possibilities are seemingly too broad, or include signals not made up of boards or that use boards as an foundation. O.S. Nock has referred to the older non-semaphore signals of Europe as "discs, diamonds and boards" (Nock 1978, 780). His usage of several terms indicate the lack of a general term; his use of board as a type of these signals suggests that as a possible general term.
There are two types of signal boards: one revolves on an axis with one position parallel with the track; the second form is hinged so that one position of the board is horizontal and one position is vertical (this form can be termed the Klappbarr, the German word for hinged). Both forms often employ a "blind edge" as a proceed indication. A third type, with a single fixed message, is rare and seemingly found only in the UAR system.
Most signal boards are free-standing units. And usually they are single units though in some systems (France for example), at least two signal boards are employed at one location in order to provide a full complement of indications (Allen, 1982, 146-7). Signal boards are sometimes combined with semaphores; for example, Spain uses a composite form of semaphore and signal board on one signal mast (RENFE 1978, 1-13). A type of semaphore arm is found with some of the hinged signal boards (termed propeller arm in this study) that augments the message capability of that signal. These are found with German systems (DB 1981, 50-51), and also in the Indonesian system (PNKA 1971, fold-out chart).
While the several types of signal boards each have individual characteristics there are no general characteristics other than the board and the mast and some kind of activating mechanism (and that is true of all signals). Signal boards are usual two-position signals and often one position is a "blind edge" indication. Chapter 32C2 reviews possibilities of the board.
The hinged or klappbarr variety of signal board are in use in DB, DR, OBB, PKP, TCDD, URO and possibily the USSR. In most instances these exist only in limited numbers. This variety is more common in Yugoslavia and in Hungary; there is some usage in Rumania. Belgium and the Netherlands in western Europe make very restricted use of similar forms of boards. The area of extensive use of signal boards - and of the revolving form - is in south- eastern Europe: France, Spain and Portugal (SNCF 1981; CP 1981; RENFE 1978). These nations maintain a full complement of signal boards; this is especially true of France and Portugal. In fact, the boards of France and of Portugal are very similar in design and function.
Outside of Europe there are signal boards in the UAR system (UAR 1983), Vietnam (ROSTEJUS, 22-23) and Algeria (SNCA 1968, RGS). These are all largely of French vintage. Indonesia (PKNA 1971), employs a variety of signal boards. It might be too fanciful to see any relationship between the signal boards and the nineteenth century disc signal of the U.S.
Signal Board Messages
The three systems with a wide range of signal boards - as well as sharing many points of commonality - will be considered as a group. The UAR, with resemblances to SNCF, will be an adjunct of the group. The Germanic sphere of influence is to be seen in signal boards in central and eastern Europe and provides an exemplar for the klappbarr form and a second group. A final group consists of remaining systems.
The "Big Three" of signal boards: France (and French-influenced systems), Portugal and Spain display similarities though national characteristics are also present. Historical exigencies, and possibly additional geographical ones, may explain the three over-lapping sub-systems of this signal. It may also be true that any railway designing a particular form of signal may parallel similar signals in other systems since railways draw from a common store of shape, and meanings.
There are parallels between the above rail systems and North America: both groups project a common core of messages through multi-form means: messages for proceed, caution and halt. No one kind of signal has a monopoly on indications. The multi-form modes include both fully-lighted and partially-lighted signals.
The three principal signal board system may be termed General Systems of Signal Boards (References for this segment include: SNCF 1981; CP 1980; RENFE 1978; see also RAN 1973, SNCA 1968, UAR 1987 and ROSTEJUS 1954 for Vietnam). The coverage includes a review of each shape and color under the headings of stop, cautionary and proceed categories. Dissimilarities among the systems will also be noted.
Stop indications are denoted by a square signal board. This is solid red in Portugal and by red/white checks in France, Spain and Vietnam. UAR employs a red board separated by white lines. The meaning of this indication is stop (or absolute stop). Portugal also includes a permissive stop signal: a square board accompanied by an upright rectangle (with the top edge cut off at a 45 degree angle). A modified stop indication is provided by the deferred ("diferida") signal of Spain and Portugal, and the disc signal of France. It is a solid red disc (CP 1981, 18; SNCF 1981; RENFE 1978, 1-11; ROSTEJUS 1954 22) .
A diamond shaped board in solid yellow denotes a precautionary signal in Portugal and Spain, and a warning signal in France. A yellow disc with diagonal black bar is found in Spain and Portugal. It is a precautionary signal in Portugal which, in some circumstances, permits a maximum speed of 45 km/h instead of the usual 30 km/h. In Spain the signal announces or advises of an upcoming stop signal. Triangle (point downward) is also within the caution category. This signal is solid yellow in Spain.
An additional cautionary board is the triangle with point downward. It is solid yellow in Spain, yellow with vertical black bar in France, and with yellow and white segments in Portugal. It advises precaution in Portugal, announces or advises precaution in Spain, and serves as a speed restriction signal in France. Triangle with point upwards is found only in France. It is employed as a distant signal of the previously described speed restriction signal.
A solid green square is provided by UAR for the clear indication. Portugal displays an upright rectangle with a triangular top edge and green and white segments for the clear indication. France and Spain use the more common "blind edge" for providing the clear indication.
A violet or purple square indicates prohibition of shunting in France, Portugal, Spain and Vietnam. A semaphore indicates shunting permitted rather than the blind edge of the aforementioned square.
Spain provides an interesting two-part composite group of signals: one part combines signal boards and semapores, and the second brings together different kinds of signal boards (RENFE 1981, 1-13, TISRP). There are four elements within the composite signals. The first consists of the semaphore and signal board (blind-edge) for proceed; semaphore and downward pointing triangle for advising /announcing of precaution (semphore upright); semaphore at 45 degree position and downward pointing triangle for announcing/advising of upcoming stop signal, and semaphore in horizontal position with the same triangle for stop. The second element is a more nuanced one: semaphore arms sometime display pointed-ends and other times blunt-ends; the signal board triangles are the same in both cases.
The third element is comprised only of signal boards. The proceed indication consists of two blind edges, for advising precaution it is one blind edge and the inevitable triangle, and for announcing stop, one disc in yellow with diagonal black bar above the triangle. There is no stop indication in this variation of the composite signals. The final element displays the indications for proceed and for announcing precaution; there are no messages of announcing of stop or a stop indication. However, there is a deferred stop message marked by a red disc and accompanied by a triangle.
The second category of signal board users is that of limited usage. Many of these are in the Germanic mode and they represent functions of distant signal indications or shunting instructions. Three other board users will be attached to this category.
DB, DR, OBB and PKP and the URO have a very similar form of klappbarr distant signal. In the stop position the signal displays a yellow disc while in the proceed indication a blind edge is displayed. Yellow or green lights are displayed at night. Turkey has this signal as well as rectangles with red center and white border (TCDD, 2-3). These signals also include a "propeller" arm semaphore mounted on the signal mast below the board. This supplemental arm remains vertical unless the distant signal denotes a divergent line. In that circumstance the disc is present to the viewer and the lighted message is G/Y. The DR has a somewhat more complex klappbarr system though in essentials it is the same. In Austria the blind edge is accompanied by a rectangle with rounded corners and displaying a white and green color pattern (for references see signal codes of listed systems).
The distant signals of Yugoslavia and Hungary bear a resemblance to the German mode but notable differences are also present. The distant signal for Yugoslavia consists of a rectangle (horizontal dimension is emphasized) or a disc. Both designs have yellow and white vertical stripes (JZ #12; MAV, 264). These represent the day indications for stop. The proceed indication is a blind edge for day usage and green light at night. The distant signal for Hungary is a yellow disc for day and yellow lamp at night. The proceed indication is a blind edge for day and a green light at night. Rumania has a very similar signal (CFR, 1).
Shunting signals for the eastern and central European systems display diversity though points in common are also present. The URO system offers a square divided into small blue and white checks (URO 1962, 20). This is the day message for shunting prohibition. At night blue signals give the same message. Shunting permitted is marked by a blind edge in the daytime and white lights at night. This shunting signal is not found in the codes viewed by this compiler other than in URO.
Yugoslavia employs a blue diamond with vertical blue and white stripes for no shunting message in the day and a blue light - set within the diamond - indicates the same message at night. Blind edge indicates shunting approved during the day and by a white light at night. Another variant form is found in Hungary and Poland where a solid blue diamond is in use. This is replaced by a blue light at night. Blind edge and white light are the messages for shunting approval (JZ Signal #4; MAV, 264; PKP 1976, 58).
Two other nations employing signal boards are those of the Netherlands and of Indonesia (NS 1978, 46; PKNA 1971). Indonesia has a variety of signal boards. A major form has three messages: red discs with red lamp (stop), and blind edge (proceed), with a green lamp, and a semaphore arm attached to the blind edgethat indicates caution, when at a 45 degree angle, with yellow light at night PNKA 1971, fold-out); another form has Green and red discs with accompanying lights for night use. The Netherlands employs a signal board for the platform signal. For day usage this is comprised of an upright rectangle in red for stop and a blind edge for proceed. At night a red lamp indicates halt and a white one indicates proceed. The signal board has side hinges as in the case of south-western European signal boards (NS 1978, 58) .
