It may be here pointed out that all the railway signal companies now in operation, installing automatic signals under whatever name, are using the Robinson system bodily, and have been since the expiration of Robinson's basic patents. There is no other system, as a system, in use.
History: Several years ago I published a "History of Automatic Electric and Electrically Controlled Fluid Pressure Signal Systems for Railroads," the only authentic history ever published on the subject.
This was written and published at the instance of engineering friends, in the interest of indisputable historical accuracy.
Telephone Experiments
1876. As a matter of more or less interest I may here state that I carried on a conversation by telephone, in 1876, through a railroad track, the circuit consisting of the two rail lines constituting a closed circuit signal block.
1877-8. Delivered numerous illustrated lectures on the telephone, and at this time discovered the principle of the wireless telephone and actually transmitted speech clearly back and forth across an open space of several inches to and from a telephone having but one terminal grounded and the other free in the air. The free, uninsulated wire (except at supports) extended several hundred feet through the air. The instruments used were large magneto telephones of my own special designing, and made by me for the special purpose of illustrating lectures. No battery was used.
Electric Railway Systems
Outside of automatic signaling I have done considerable work along original electrical lines.
In addition to other work of importance I have for more than fifteen years devoted much time to developing a radically new departure in electric railroading.
On this system I have applied for more than twenty patents, extending over a series of years, fourteen of which patents have already been issued.