AN IMPROVED AUTOMATIC RAILWAY FOG SIGNAL APPARATUS
Year: 1880

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PROVISIONAL SPECIFICATION left by Henry Whitehead and Ralph Hodgson
at the Office of the Commissioners of Patents on the 7th February 1880.
HENRY WHITEHEAD, of Bucknall, in the County of Stafford, Coal Merchant,
and RALPH HODGSON, of Winsford, in the County of Chester. "AN IMPROVED
AUTOMATIC RAILWAY FOG SIGNAL APPARATUS."
The object of this Invention is to provide the mechanical apparatus, hereinafter
described, which is to effect automatically that which is now done by hand
It is the custom in foggy weather to station an additional man at each distant
signal box, or otherwise, as required, whose duty it is to place fog signals as they
may be needed on the metals so as to warn an approaching train, the explosion of
one detonating signal being generally employed to signify "caution," and two to
signify "danger.'
It is obvious that this system not only entails considerable expense on the
railway company, but it is attended with danger to the man engaged, and the men
so employed cannot always be depended upon.
All these evils are obviated by our improved apparatus, as we will now proceed to
shew. In doing this we must claim for our Invention that it can be attached to
the ordinary semaphore signals without difficulty or without any increase in the
connecting wires now employed for working the said semaphore signals.
Our Invention is substantially carried into effect by providing a crank keyed
upon a shaft, upon which are also keyed two propelling drivers, which are provided
for the purpose of propelling the slides employed to carry the fog signals (one at a
time) from under the tubes (hereinafter explained) to the anvil, where the said
signals are afterwards exploded by means of a hammer falling upon them, the said
hammer being actuated by the flange of the wheel of the first carriage of which the
train may be composed coming against and depressing a lever in connection with the
said hammer.
The tubes employed, to which reference has been made, and of which there are
two, are for the purpose of holding the fog signals, which may be of the ordinary
kind. Two balance weights are provided at the rear of the apparatus by means of
which the hammer is raised after an explosion has been effected, and the slides are
then free to be withdrawn into their normal positions. Upon each of the slides is
fixed a stud which, being withdrawn with the slides, is caused to come into contact

page_text: with the heel of the hammers, and thus draws them down to a point where they
are clear of any passing train.
It should be mentioned that the crank which gives motion to the whole of our
contrivance is connected by any convenient means with the present semaphore
signal, so that the same man employed to work these signals at the same time (and
automatically) works our Invention.
Our Invention is so contrived that upon the semaphore being raised to "caution"
only one of the two slides of our apparatus will come into action, and thus only
one signal be exploded; but upon the signal being raised to its full height both of
the two slides will be actuated, and as both will carry a signal there will be two
explosions, and "danger" will be immediately known.
Upon the dropping of the semaphore arm to its normal position both of the
slides are withdrawn to theirs, the said slides withdrawing in their turn the
exploded signals to a receptacle or box provided for them.
In some cases it may happen that after the signals have been, by the means
herein before explained, placed in position, the expected danger may not longer be
feared or "caution" not be needed. When this occurs the falling of the arm will
withdraw the slides, and these will carry the unexploded signals into the same
receptacle or box before they are exploded by the hammer, the lever connected
with which being subsequently, by the same automatic action, withdrawn from
contact with the approaching train.