IMPROVEMENTS IN SIGNALLING ON RAILWAY TRAINS
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by Francis Sanders at the Office of
the Commissioners of Patents, with his Petition, on the 3rd March
1874. A communication from abroad by Richard David Sanders,
of Bombay, in the Empire of British India, Engineer.
I, FRANCIS SANDERS, of Birmingham, in the County of Warwick,
Attorney and Solicitor, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN SIGNALLING ON RAILWAY TRAINS," to be as
follows:-
.
The said Invention consists of improvements in or additions to an
Invention for which Letters Patent were granted to me on the 19th day
of February 1873, No. 625.
any
of
The signalling apparatus described in the Specification of the said
Patent consists essentially of an arrangement or combination of parts,
whereby signalling is effected between the driver of the train and
the passengers by the opening of a valve or stop-cock by the passenger.
The like signalling is also effected by the rupture of the train or by the
opening in any way of the pipe to which the stop-cocks referred to are
connected.

page_text: The said arrangement of parts consists essentially of an air receiver or
cistern into which air is condensed by means of a condensing air pump
driven by the locomotive engine or worked by hand.
In communication with the air receiver is a vertical hollow cylinder
having within it a disc or piston working freely therein. The cylinder
is closed at top and bottom, the bottom of the cylinder being in com-
munication with the cistern of condensed air, and the top of the cylinder
is in communication with a pipe running along the whole train, and
having branch pipes with stop-cocks terminating in each partition
between different divisions of the carriages of the train. The rod of the
said disc or piston in the cylinder passes through the bottom of the
cylinder, and its outer end is connected to the lever of the cock or tap.
When the disc or piston is raised in the cylinder the last described cock
or tap is opened, and a steam whistle brought into operation and an
alarm sounded.
In the normal state of the apparatus there is no escape of air from the
pipes fixed to the carriages except by leakage, and the quantity of air
necessary to replace this passes between the piston and the cylinder, or
through a small hole in the piston without raising the said piston. But
if by the opening of a stop-cock or the rupture of the pipe running
along the train air is allowed to escape, the pressure of the air on the
under side of the piston being no longer counterbalanced by a like
pressure on its upper side, the said piston is raised and by its rising it
opens the stop-cock and an alarm is sounded.
n
It is stated in the said Specification that the same effect may be pro-
duced by the exhaustion of the pipes on the carriages by means of a
pump or by a steam jet, and the present Invention consists of the new
or improved construction and arrangement of parts herein-after described
for effecting the signalling by means of exhaustion produced by a steam
jet or injector.
The said new or improved construction and arrangement of parts are
as follows:-The air receiver and condensing air pumps described in the
Specification of the Patent referred to are dispensed with, and there is
fixed by preference near the engine driver and on the fire-box end of the
locomotive a vertical hollow cylinder containing a piston, the rod of
which passes through the bottom of the cylinder and is connected with
the lever of a steam whistle. The bottom of the cylinder is in com

page_text: munication with the pipe running along the carriages and having branch
pipes of the kind herein-before described. The piston fits the cylinder
loosely or has a small hole in it. On the top of the cylinder is a steam
jet or injector of the kind commonly used for injecting feed water into
steam boilers, the exhaust side of the said steam jet or injector opening
into the top of the cylinder. A steam pipe from the boiler supplies
steam to the said steam jet or injector, and is also in communication
with a steam whistle. The fore end of the steam jet or injector ter-
minates in a pipe which conveys the waste steam to the tender. The
waste steam is condensed in the water of the tender, and by heating the
said water fuel is economized.
The action of the apparatus is as follows:-In its normal state there
is an exhaustion both in the upper and lower parts of the cylinder, and
in the system of pipes communicating with the lower part of the
cylinder, the exhaustion being produced by the action of the steam jet
or injector.
When by the opening of a stop-cock by a passenger or the rupture of
the pipe running along the carriages air is admitted into the said pipe,
the said air entering the cylinder at its bottom lifts the piston in the said
cylinder, and thereby opening the stop-cock of the steam whistle
occasions the sounding of the said whistle.
When the apparatus is first put into operation or after the filling of
the apparatus with air by the opening of one of the stop-cocks or other-
wise the action of the steam jet or injector in the course of a few
seconds restores the exhaustion of the pipes, and the apparatus is again
ready for signalling.