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16,37 France had an extensive optical telegraph system dating from Napoleonic times and was even slower to take up electrical systems. However, in trying to get railway companies to take up his telegraph more widely for railway signalling, Cooke was rejected several times in favour of the more familiar, but shorter range, steam-powered pneumatic signalling. Schilling's telegraph was tested on a 5-kilometre-long (3.1 mi) experimental underground and underwater cable, laid around the building of the main Admiralty in Saint Petersburg and was approved for a telegraph between the imperial palace at Peterhof and the naval base at Kronstadt. An early experimental system (Schilling, 1832) led to a proposal to establish a telegraph between St Petersburg and Kronstadt, but it was never completed. This led to the formation of labor organizations to represent the workers and advocate for their safety. This emphasis on precise time has led to major societal changes such as the concept of the time value of money. The concept of a signalling "block" system was proposed by Cooke in 1842. Railway signal telegraphy did not change in essence from Cooke's initial concept for more than a century.

In Cooke's original system, a single-needle telegraph was adapted to indicate just two messages: "Line Clear" and "Line Blocked". Even when his telegraph was taken up, it was considered experimental and the company backed out of a plan to finance extending the telegraph line out to Slough. As late as 1844, after the electrical telegraph had come into use, the Admiralty's optical telegraph was still used, although it was accepted that poor weather ruled it out on many days of the year. A decision to replace the system with an electric telegraph was made in 1846, but it took a decade before it was fully taken out of service. Commercial electric power was initially transmitted at the same voltage used by lighting and mechanical loads. The first commercial telegraph was by Cooke and Wheatstone following their English patent of 10 June 1837. It was demonstrated on the London and Birmingham Railway in July of the same year. The same catalogue included lampholder plugs for both BC and ES lampholders (capacity unspecified), and also a type of two-pole concentric plug and socket (similar to a very large version of the concentric connectors used for laptop PC power connections) in the "1 to 5 lights" and "5 to 10 lights" capacities.

Having only one type of motive power also allows greater fleet homogeneity which can also reduce costs. The idea for a telegraph of this type was first proposed as a modification of surveying equipment (Gauss, 1821). Various uses of mirrors were made for communication in the following years, mostly for military purposes, but the first device to become widely used was a heliograph with a moveable mirror (Mance, 1869). The system was used by the French during the 1870-71 siege of Paris, with night-time signalling using kerosene lamps as the source of light. Both electrostatic and electromagnetic induction were used to develop wireless telegraph systems that saw limited commercial application. Prior to the War the telegraph systems were primarily used in the commercial sector. The last commercial semaphore link ceased operation in Sweden in 1880. As of 1895, France still operated coastal commercial semaphore telegraph stations, for ship-to-shore communication. The first operative electric telegraph (Gauss and Weber, 1833) connected Göttingen Observatory to the Institute of Physics about 1 km away during experimental investigations of the geomagnetic field. Entry to and exit from the block was to be authorised by electric telegraph and signalled by the line-side semaphore signals, so that only a single train could occupy the rails.

Wigwag was used extensively during the American Civil War where it filled a gap left by the electrical telegraph. Likewise, the United States continued to use American Morse code internally, requiring translation operators skilled in both codes for international messages. A heliograph is a telegraph that transmits messages by flashing sunlight with a mirror, usually using Morse code. Although the electrical telegraph had been in use for more than a decade, the network did not yet reach everywhere and portable, ruggedized equipment suitable for military use was not immediately available. However, this led to a breakthrough for the electric telegraph, as up to this point the Great Western had insisted on exclusive use and refused Cooke permission to open public telegraph offices. These drives can run equally well on DC or AC of any frequency, and many modern electric locomotives are designed to handle different supply voltages and frequencies to simplify cross-border operation. We can say, simplifying, what is electric cable a shielded cable should be better able to immunize transported signals. The signaller would adjust his line-side signals accordingly.