IMPROVEMENTS IN SIGNAL APPARATUS FOR RAILWAYS
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by John Foster at the Office of the
Commissioners of Patents, with his Petition, on the 13th October
1873.
I, JOHN FOSTER, of Lower Wandsworth Road, Battersea, in the
County of Surrey, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN SIGNAL APPARATUS FOR RAILWAYS," to be as follows:
-
The Invention relates to improvements in means for indicating to the
signalman the position of the arm at the distant signal in cases where
such distant signal is out of sight or in other desirable cases, as also to
means for indicating to the signalman whether the light at the signal
post is in or out.
According to the present Invention a "repeater" is employed which
will indicate to the signalman the exact position of the distant signal
arm, whether such arm is "on," "half off," or wholly off," as also
whether the light is out or in.
66
For the purpose of indicating to the signalman the position of the
distant signal arm the following arrangement is employed :-
On the distant post are two plates and a steel spring attached to the
arm, one end of each plate being in connection with one pole of the

page_text: battery and the other end being in connection with the other pole, con-
sequently when the arm is moved it has to pass the first plate and comes
in contact with the second; by that time the distant signal is half way
down, then a current is sent along a communicating wire to the
"repeater" and lowers a corresponding arm therein.
When the current is sent a piece of soft iron is attracted to an electro-
magnet, and prevents the arm in the repeater going more than half way
down by a stop mounted on the axis of the arm coming in contact with
another stop, a needle (worked from coils) is attracted either to the right
or left according to which direction the arm at the distant post is
going.
"
When the distant signal arm has passed the second plate it is "down"
and the current is exhausted, and the piece of soft iron is released from
the electro-magnet and causes the " repeater to fall accordingly.
Two pieces of soft iron are employed to repel and retain the needle, and 1
a stop is employed to prevent the soft iron going beyond its distance,
and a spiral spring puts the soft iron back to its proper position after the
current is released at the distant post, and causes the arm in the
"repeater to fall in accordance with the arm at the distant post.
"
"
At night time a lamp is used at the distant post to show whether the
signal is " on or "off," sometimes on windy nights the lamp is
extinguished and at present the man on duty in the box cannot tell if
such is the case.
"
According to my Invention however I provide means whereby the
repeater" will indicate to the signalman immediately whether the s
light is in or out. For this purpose I mount on the "repeater” another
pair of coils which are in connection with the communicating wire to
the lamp; if it should happen that the light be extinguished a current
subsequently passes through the communicating wire and causes a
"needle "
to pass over to the right, which raises a corresponding
"needle" on the " repeater" to "light out;" then when the lamp is relit
the "needle " on the "repeater" drops to "light in."
For this purpose
the light or its absence is caused to act on a column of mercury to
effect the making and breaking of electric connection, or other suitable
means may be employed as is well understood.
A counterbalance is employed in connection with the "needle" of the
light "repeater” or indicator. When the light is extinguished the

page_text: current causes the needle to point to the right and raises the indicator to
"light out," when the current is released by the lamp being lighted the
"needle" is brought back to its former position by the counterbalance
and the indicator to "light out.".
It is well known that in operating ordinary "repeaters" it is necessary
to have a persistent current of electricity travelling along the com-
municating wire all the time the "repeater" is "on" or "off," but
according to my Invention the "needle" is a magnet with north and
south poles, consequently when a current has been sent through the coils
there is a sufficient amount of magnetism in the horns to hold the
"needle" in the last position it was placed, and there it remains to such
time as it is removed by the action of the distant arm, by which it will
be seen that the apparatus is self-locking.
Another advantage to railway companies in this "repeater" is that
the battery is only in work when the man is pulling the signal "on
" or
" off."
In case an accident should occur and the signalman broke the glass to
throw the blame on the "repeater" by putting the arm down or up
as the case may be, the instrument will right itself to the position in
accordance with the arm at the distant post.