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Semaphore signals were patented in the early 1840s by Joseph James Stevens, and soon became the most widely used form of mechanical signal. Designs have altered over the intervening years, and colour light signals have replaced semaphore signals in most countries, but in a few they remain in use.
A semaphore signal on the Atchison, Topeka and Santa Fe Railway in 1943. Semaphore signals were first developed in England in 1841. [2]: 169 Some U.S. railroads began to install them in the early 1860s, and semaphores gradually displaced other types of signals. The Union Switch & Signal company (US&S) introduced an electro-pneumatic design in ...
Semaphore (lit. ' apparatus for signalling '; from Ancient Greek σῆμα (sêma) 'mark, sign, token' and Greek -φόρος (-phóros) 'bearer, carrier') [1] is the use of an apparatus to create a visual signal transmitted over distance. [2] [3] A semaphore can be performed with devices including: fire, lights, flags, sunlight, and moving arms.
Diagrams and maps of Murray's U.K. semaphore stations; Chart of Murray's shutter-semaphore code; Photo and diagrams of Popham's U.K. semaphore stations; Map of visual telegraph (semaphore) and electrical telegraph lines in Italy, 1860 (in Italian) Details on the history of the Blanc brothers fraudulant use of the Semophore line
Railway signal mast}} is a template for displaying signals on a mast for demonstration of railroad signalling aspects. It displays up to three signal heads using spotlight, one of two types of semaphore, or positional signals, along with a base and modifier plates.
When describing an older semaphore, "on" refers to a signal arm in the horizontal position, and "off" means a signal raised upwards or lowered downwards from pivot point (at up to 60°). With regard to newer colour-light signals, "on" is synonymous with the most restrictive aspect, while all other aspects are considered to be "off".
The International Code of Signals (INTERCO) is an international system of signals and codes for use by vessels to communicate important messages regarding safety of navigation and related matters. Signals can be sent by flaghoist , signal lamp ("blinker"), flag semaphore , radiotelegraphy, and radiotelephony.
All aspects are indicated with colour light signals. Despite this re-signalling, some parts of the TransAdelaide network still use the original 3-position speed signalling (such as the Dry Creek to Port Adelaide line). There is also a low speed aspect indicated by a lunar-white position-light signal mounted below the main head.