IMPROVEMENTS IN THE MEANS OF COMMUNICATION BETWEEN THE PASSENGERS AND GUARD OR THE GUARD AND DRIVER OF RAILWAY TRAINS
Year: 1865

page_text: PROVISIONAL SPECIFICATION left by Sanders Trotman at the Office of
the Commissioners of Patents, with his Petition, on the 6th May 1865.
I, SANDERS TROTMAN, of No. 11, Lyme Street, Camden Town, in the County
of Middlesex, Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE MEANS OF COMMUNICATION BETWEEN THE PASSENGERS
AND GUARD OR THE GUARD AND DRIVER OF RAILWAY TRAINS," to be as follows:-
My Invention has for its object an improved means of communication
between the passengers and guard, and the guard and driver of railway trains
whilst in motion.
In carrying out my Invention I employ as a signal a ball that may be caused
to become mobile at will by releasing it from a fixed position and causing
it to enter a pneumatic tube passing through the entire length of the train.
The tube I employ I prefer to be fixed by proper standards upon the centre
of the roof of the carriages in such manner that a uniform height for the
tube is attained throughout the rolling stock, each carriage carrying its pro-
portionate length of the tube, the junction being formed of an elastic material
or a combination of materials, part elastic and part rigid. The junction I
prefer consists of an elastic tube with thickened ends equivalent to a ligature
and formed in the same material, which ligatures being strapped over the ends
of the tube already wired or otherwise prepared to receive it form an air-tight

page_text: and elastic connection between the several sections of tube upon the carriages
which compose the train. At such parts of the carriages as the signal may
be required I place a shorter tube of the same diameter in connection with
the pneumatic tube of a sufficient heiglit to contain the signal ball, which ball
is retained in position by a pin, on the withdrawal of which the signal ball
enters the pneumatic tube and is drawn as hereafter described through its
length into the guard's van. For the transit of the signal ball I prefer to
use a fan or air pump for exhausting the pneumatic tube during the whole
time the train is in motion, which said fan or pump may be worked by a
rigger and band or excentric taking its motion from the axle of tlie wheel of
the guard's van. When the signal ball having been drawn through the
pneumatic tube, arrives at the end of the same in the guard's van, it is arrested
by a pin traversing the tube, and thus the passage of the air through the tube
is prevented; on this obstruction taking place the atmospheric air will be
sharply drawn through an orifice connecting a whistle with the tube, and thus
alarming the guard. The end of the tube where the arrest of the signal ball
takes place should contain a door so that the signal ball being numbered the
same as the carriage or compartment, or according to the numerical distance
of the carriage or compartment from which it has been drawn from the
guard's van, the guard is enabled by the inspection of the ball to tell the
carriage or compartment from which the signal has been given. Each
compartment is provided with a pull or handle communicating by means of a
bell crank or otherwise with the pin keeping the signal ball in position, on
pulling the handle the pin before referred to is withdrawn, the ball thereby
released enters the tube signalling as before described. On making up the
train the carriage or compartment should be numbered consecutively from
the guard's van by the signal balls, each of which should have an impressed
numeral corresponding therewith. A supply of these signal balls should be
kept at each of the principal stations and all stations where trains are made
On remaking the train, the signal balls should be rearranged so that
the numbers count consecutively from the guard's van, the open end of the
tube or that end next the engine, may be provided when necessary with a
moveable cap, at the end of which is a flap valve opening inwards, and nea
the end of which is a whistle, which valve will be caused to shut and the
whistle to sound by the guard reversing the pump or fan so as to create
pressure within the tube instead of exhaustion as required by the first mode
of signalling. The second mode of signalling will enable the guard instan
taneously to communicate with the engine driver in case it be necessary t
stop the train.
up.

page_text: It should be understood that I do not claim as my Invention a pneumatic
tube or the sounding of an alarm or whistle by compressed air or exhaustion,
but what I do claim as my Invention is,―
Firstly, the mobile signal ball and apparatus for signalling with the same.
And, secondly, the combination of the mobile signal ball and apparatus
with the pneumatic tube and alarm or whistle as berein-before described.