A NEW OR IMPROVED MODE AND MEANS OF OR ADAPTATION OF MECHANISM FOR MAKING ALARM SIGNALS ON RAILWAYS TO PREVENT COLLISIONS
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by Stenhouse Bairnsfather at the
Office of the Commissioners of Patents, with his Petition, on the
19th February 1875.
I, STENHOUSE BAIRNSFATHER, of the City of Glasgow, in the County
of Lanark, North Britain, Accountant, do hereby declare the nature
of the said Invention for "A NEW OR IMPROVED MODE AND MEANS OF
OR ADAPTATION OF MECHANISM FOR MAKING ALARM SIGNALS ON RAILWAYS TO
PREVENT COLLISIONS," to be as follows:-
This said Invention consists generally of an improved construction and
arrangement of mechanism for giving an audible alarm signal by a bell
or gong to the engineer and conductor (or other person) in charge of any
train approaching a station at which a previous train had stopped, and
in sufficient time and at such a distance therefrom as to enable them
with ease to stop their train before reaching the one at the station,
where an arrangement of this improved alarm signalling apparatus
would be erected for this purpose, all so as to prevent collisions in such
circumstances more effectually than has been the case with the modes
and means heretofore employed, more especically requisite in foggy
weather when ordinary signals cannot be seen or used.

page_text: The nature and novelty of the Invention or construction of the
mechanism and mode of working or applying it (according to one
arrangement thereof, but susceptible of considerable modification in the
minor parts) consist all as follows:-A small antifriction roller or
pulley is carried on the lower end of the front" fender" arm for clearing
the rail or other equivalent bracket for the purpose on the locomotive
engine, or it might be on the brake van, where the engineer or the
brakesman is, so that he may hear the sound of the alarm bell when
sounded as they are passing it, and the actuating mechanism erected at
a point 600 yards or more before reaching the stations where trains had
to stop. The said pulley depresses a long angled or curved lever,
fulcrumed on a transverse axle close below one of the two lines of rail,
so that the lever lies nearly horizontally along the side of the rail, and
when depressed it turns a two armed vertically disposed lever keyed
on the other end of the axle.
The two free ends of the vertical levers are connected diagonally or
otherwise by rods to the arms of a corresponding axle and angled and
curved lever mounted at the side of the rail about 20 feet or so in
advance of the other, so that when the first curved lever is depressed as
stated, the second is raised and vice versa, but when it is raised another
horizontal lever (keyed on the same axle or it might be connected to the
curved lever), lifts a long vertical reciprocating rod (attached to it at
the lower end) and to one end of the bell hammer lever by a slot at
its top end of the alarm mechanism placed some little distance off the
track of the line of rails and carriages.
The bell or gong is carried on a convenient part of the frame carrying
the striking mechanism, which consists of the hammer carried on the
free end of a longish upright lever keyed on the same spindle as the
shorter two armed lever, having one end connected to its actuating spiral
or other spring, while the other is connected by a lateral pin to the long
slot in the upper end of the vertically reciprocating rod of the forward
curved lever at the side of the rails before mentioned.
The bell hammer lever has a catch arm or notch on it, which when
raised (as the roller on the engine passes over and depresses the said
second curved lever by the slot in its vertical rod against the power of
its striking spring) is exactly under, and held there by a spring catch or
pall until released, first, when a train is standing blocking up the line at
the station the roller of the engine of the next following train depressing

page_text: the first of the two curved levers and raising the slotted vertical rod
(through the vertical levers and their connecting rod), which by a
stop hinge pall at the top releases the holding catch of the hammer
so that it strikes the bell by the power of its spring, this giving the
alarm to the persons on the train passing to put on their breaks in time
to stop it before reaching the train standing at the station, and in
passing presses down the second curved lever, raises and sets the
hammer lever again ready to alarm the persons on the next train. Or,
secondly, when the first train has passed on 500 yards or so beyond the
station the depressing pulley on its engine presses down another curved
lever fitted at the rails at this point much the same as the others, except
that its downward motion moves a crank through a long connecting
pulley, wire, or rod which is conducted back over carrying rollers and
connected to a bell crank, attached to a strong spring connected by
another duplex or stop hinge disengaging pall of the bell mechanism,
and releases the holding spring catch of the bell lever which falls, and
therefore when the next engine or train comes up it cannot sound the
alarm bell in passing over the first curved lever, but will raise and
engage it all ready for giving the alarm to the following train until after
it has passed on out of the station to the advanced curved lever beyond,
when it will disengage the holding catch of the bell hammer, and show
all clear to that train, all as before described, for each succesive train
passing the stations, fitted with this improved alarm mechanism, and
bell or gong, which must be large and give a good loud sound to be heard
by the person on the train in all kinds of weather above the sound of
wind and rain.
When desired balance springs or weights might be fitted to levers
connected to the curved levers (or rods connecting them to the other
working parts), to retain them in their normal position as set by the
antifriction pulley of the locomotive engine for moving these curved
levers, which with the improved alarm mechanism would be fitted as
described at every station or part of both the up and down lines where
trains had to stop, all substantially as described.