IMPROVEMENTS IN AND RELATING TO FOG SIGNALLING ON RAILWAYS, & IN APPARATUS THEREFOR."
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by John Vernon Hope at the Office of
the Cominissioners of Patents on the 31st March 1877.
JOHN VERNON HOPE, of Liverpool, in the County of Lancaster. "IMPROVEMENTS
IN AND RELATING TO FOG SIGNALLING ON RAILWAYS, & IN APPARATUS THEREFOR."
This Invention consists in a method of and apparatus for exploding ordinary fog
signals off the rails, but by the action of a passing train, and in a mode of working
that apparatus.
I placo the signals, consisting of ordinary round fog signals, one over the other in
a vertical cylindrical chamber a few feet from the line, sufficiently far off to clear
the train. This chamber has its sides cut away above the bed plate of the machine
a sufficient height to allow one fog signal at a time to be pushed out through the
aperture. Adjoining this chamber, and at right angles to the rail, is a stout flexible
lever, preferably steel, jointed securely at the end furthest from the rail to a firm
support, but capable of rotating vertically on this pivot. Where it passes the
chamber I expand the said lever out into a solid block, or attach a block to the
under surface thereof, and from this point to the joint make the lever much more
rigid. A series of bell-crank or other levers and links connect this lever with a
pusher, that as the aforesaid block on this bar is pressed down and springs back a
fog signal is pushed from the base of the signal station under the block. The end
of the main lever is secured in a hole or jointed to a bar running alongside the rail
and projecting above it, so that as the train runs over and depresses this bar it shall
depress the transverse lever and explode the signal beneath it. Two of these
machines are usually attached to the bar, one for danger, the other for caution.
In order to prevent the machines acting with every train a bar, called the
signalling bar, with two blocks on it, runs parallel to the rail, the two blocks being
so arranged that one or both of them can be made to slide under the levers, and
prevent them from deflecting near the detonating block. This bar is pulled by wire
from the signal station, and is counterweighted so as to always fly to danger if the
wire breaks.
The long bar is made, preferably, of angle iron, and is so long that at least one
wheel of a passing train will always be over it. It is supported at each end on
stout springs and studs, and so arranged that either or both ends of the rail being
depressed by a passing wheel neither can rise until the entire train has passed over.
CD 0.71

page_text: The mode of operating it is as follows:-When there is no fog the signalling bar is
drawn back by the pointsman so that both blocks are below the main levers. The
trains then running on the lines depress the main bar and deflect the ends only of
the main elastic levers. If however there is a fog and the signal "caution" is to
be given the signalling bar is released sufficiently for one of the blocks to slide from
under the main lever above it. The next train then depresses that lever and
explodes a signal under the block; the bell-crank lever at the same time is pushed
aside from under the signal chamber. When the lever is released from the pressure
of the passing train it recoils the bell-crank lever, brings another fog signal beneath
it, ejecting the exploded one, thus leaving it ready for next train.