IMPROVEMENTS IN APPARATUS FOR SIGNALLING ON RAILWAYS
Year: 1871

page_text: PROVISIONAL SPECIFICATION left by George Edward Price at the
Office of the Commissioners of Patents, with his Petition, on the
29th March 1871.
I, GEORGE EDWARD PRICE, Lieutenant in the Royal Navy, of Her.
Majesty's Ship Agincourt, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN APPARATUS FOR SIGNALLING ON RAILWAYS,"
to be as follows :-
This Invention has for its object improvements in apparatus for
signalling on railways.
At the present time when any sudden emergency arises it is usual to
lay fog signals on the rails to notify the same to approaching trains.
To do this effectually long distances have to be traversed by the operator,
and during the time this occupies the obstruction is unprotected..
Now according to my Invention I station fog signals at short dis-
tances apart along the line of railway, or such portion thereof as it is
desired to protect, and I employ electricity to fire them by means of
two insulated wires applied in such manner that when an electric com-
munication is made with one of them at any place it will determine the

page_text: explosion of all the fog signals within a given prearranged distance
from such place at the time when a train next passes the signals. One
of the insulated wires is in connection with one terminal of a battery
(or batteries), the other terminal of which is to earth, and care is taken
to maintain the charge in the wire with as little variation as possible.
The other insulated wire is so constructed as to offer considerable
resistance to the flow of an electric current, so that a current from the
battery wire having to flow through a long length of the resisting wire
will be unable to discharge the fog signals, but will do so if the distance
is short, say, for example, a mile or less. The distance can be adjusted
by regulating the resistance, which is conveniently obtained by means
of resistance coils.
Each time that a train passes one of the fog signals it causes a contact
between the battery wire and a wire passing to a fuse or instrument for
firing the signal, and so to the resisting wirc. This contact may be
made by a vibrator set in motion by the passage of the train in close
vicinity to it or otherwise. If at the time this' contact is made the
resisting wire has been put in connection with the earth at any point
not very distant the signal will be exploded, but if there be no such
earth connection, or if there be an earth connection only through a
long length of the resisting wire, the signal will not be discharged.
The earth connections may be made in any simple manner, as by means
of a button provided on each of the telegraph posts. At junctions and
points the switch and signal levers may make and brake the carth
connections at suitable times, and the same may also be effected by the
gates at level crossings.
In a similar manner the passage of a train along the line may be
caused to put to earth the portion of the resisting wire behind the train,
and then another train following the first within the distance to which
the resistance is adjusted will fire the signals. I employ explosive
signals as the means best suited to my purpose for giving an efficient
indication of the passage of an electric current.