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EXPOSITION AT VIENNA.
6. Signals to be Used in Case of Accident.
The sixth of the classes into which I have divided railway signals is also small, and contains little which has not already been alluded to under another head. Only one apparatus constructed solely and specially for a "distress-signal” is on exhibition at Vienna.
On some of the French roads, a Morse or other speaking telegraph is carried on each train, to be attached to the line in case of accident. On others, as that of the Compagnie du JYord, a dial telegraph is placed at intervals of about two and one- half miles. The number of these on the lines of that company, is between two and three hundred. They are arranged like the Siemens signal, described in class 1, so that shutting the door of the signal-box, closes the circuit automatically.
Messrs. Siemens & Halske have in their case, at the Exposition, an apparatus consisting of an upright iron standard, surmounted by a signal-box, in winch is placed appropriate clock-work. These boxes are placed at short intervals along the road, and on each train is carried a set of keys of different length, corresponding in number to the number of signals embraced in the code. Each key, therefore, has its corresponding signal in a code, similiar to that used in the system of Mantelli (Plate II). In case of an accident, the signal desired is produced by inserting the proper key in an aperture in the signal-box. The clock-work is released, and an electric circuit is automatically closed and opened a certain number of times, according to the length of the key. Whenever the circuit is closed, a bell is rung at the box, and another at the station from which assistance is expected. At the latter, the closing of the circuit also automatically releases a series of clock-work, carrying a strip of paper, as in the ordinary Morse register, on which paper the code signal is printed.
Where accidents result from, or lead to, the displacements of rails, it would seem possible (by an application of the principle of Mr. Pope’s block-signal), in the one case, to prevent them by advising a coming train of the displacement, or in the other, to notify, by electric and automatic means, a station from which assistance may be obtained.
ROBERT B. LINES.