IMPROVED MEANS OF AND APPARATUS FOR SIGNALLING ON RAILWAYS WITH THE AID OF ELECTRICITY
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by Charles Alexander Calvert at
the Office of the Commissioners of Patents, with his Petition, on
the 2nd June 1875.
I, CHARLES ALEXANDER CALVERT, of Petersham, in the County of
Surrey, do hereby declare the nature of the said Invention for "IMPROVED
MEANS OF AND APPARATUS FOR SIGNALLING ON RAILWAYS WITH THE AID OF
ELECTRICITY," to be as follows:-
The object of this Invention is the provision of automatic means of
communicating by the agency of electricity between the directors or
managers of the traffic at railway stations or other points upon a
railway, and the guards of a travelling train or between the guards of
travelling trains, for the prevention of collisions or accidents or other
disasters, otherwise especially likely to occur at a break down or with
the ordinary run of traffic, or upon a train becoming delayed suddenly
by accident or otherwise, or at crossings, or upon a single line of railway,
and by the employment of which means warning can be given in time
from a station or other desirable point of a railway to the guards of
trains approaching danger, or between the guards of trains simul-

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and between whom, if necessary, ordinary electrical communication may
subsequently be effected to ascertain the reason or cause of the first, the
stopping or danger signal.
The Invention is designed to attain these very necessary objects to
secure the safety of railway traffic with the most simple arrangement
and combination of parts.
The following description will enable any practical man to understand
the principle, application, and utility of my Invention:-The signals
between the directors or managers of the traffic and the guards of the
travelling trains, and the signals between the guards of the travelling
trains, I prefer to be communicated through separate wires insulated or
otherwise, each wire thus having its specific signalling function, and to
this end I use for each series of signals one or more wires laid between,
under, or alongside the rails, or carried by short or high posts above the
ground at any suitable elevation at short or necessary intervals, upon or
with which I connect a series of tapping levers, by the depressing of or
contact with which by a suitable appliance attached to, carried by, and
projecting (by preference) from the guard's carriage, proper electrical
contact is made; it will thus be seen that if at any time the station
master or other director or manager of the traffic wishes to communicate
with a going or coming train which may be approaching danger (from
any cause which the driver of the train would not otherwise become
cognizant of in time to avert disaster), the charges the wire from the
station battery. When the train reaches the first tapping lever,
electrical communication or circuit is completed and the desired
stopping or danger signal is exhibited (or may be sounded) in the
guard's van in a most conspicuous position. The wire may thus be
charged so that the signal shall anticipate the arrival of the train; and
communication be completed at the instant of arrival of the train. The
guard can then descend from his van (having previously communicated
by the ordinary means with the driver to stop), and can attach his
electrical connection from his van battery with the charged wire from
the station battery, and communicate direct with the station to ascertain
the necessity of the delay. It will consequently be seen that the guard
of a train delayed suddenly by accident or otherwise can attach his
appliance to any of the wires at the tapping levers, and communicate
either with the station or charge any of the wires with the tapping
6

page_text: levers of which other trains will subsequently make connection, thus
the guards of trains can communicate with each other when necessary,
each attaching his electrical connection with the same wire, the wires
only being charged so long as this connection is retained and as there
is necessity for the signalling. This latter communication will be
especially available for and applicable to the crossings or tracks of one
line of railway; thus a train in the act of passing a crossing or entering
the track of the single line by depressing or making contact with a
tapping lever, charges the proper wires, so that proper warning may be
given to any train at the same time also approaching upon its arriving
at any of the tapping levers on the same wire.