the Passage of Trains on Railways.
Year: 1885

page_text: the Passage of Trains on Railways.
I, JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex,
Gentleman do hereby declare the nature of said Invention for "IMPROVED
APPARATUS FOR AUTOMATICALLY INDICATING OR SIGNALLING THE PASSAGE OF
TRAINS ON RAILWAYS which Invention has been communicated to me from
abroad by Henri Lebasteur and Messieurs Mignon and Rouart of Paris in the
Republic of France, Engineers to be as follows:-
This Invention relates to an apparatus for indicating automatically and at a
distance the passage of trains over the part of the track to which the said apparatus
is applied.
The object of the Invention is to enable a train on passing over any point on a
railway to operate a signalling apparatus and thereby signal or give indications of
its passage with unfailing accuracy.
When a train is passing over a Railway rail the rail bends between the chairs
or sleepers under the weight of the vehicles and although the extent of this deflec-
tion is very slight it is nevertheless sufficient to actuate an apparatus possessing
the requisite sensitiveness These deflections of the rail are utilised according to
this Invention for operating a signalling apparatus arranged as hereinafter described
or otherwise.
In a block of cast iron or other unyielding material is formed a hollow or
chamber closed by a very thin sheet of brass or other suitable material joined at its
edges to the cast iron block so that the hollow space in the block forms a closed
chamber with one side formed of flexible material. This chamber is filled with an
incongealable liquid and communicates through a pipe with the tube of a Bourdon
or other manometer.
The apparatus thus arranged is placed under the rail being supported upon a
short length of rail for example attached at its extremities only to the rail above
the apparatus.
The apparatus being thus secured beneath the rail a block of steel placed upon
the yielding cover of the chamber is brought into contact with the underside of
the rail by means of a wedge or incline operated by an adjusting screw for
example.

page_text: When the liquid in the apparatus is thus to a certain extent placed under
pressure every deflection of the rail has the effect of bulging the thin sheet or mem-
brane covering the chamber in the block so as to press upon the liquid contained in
the chamber and cause it to transmit this pressure to the tube of the manometer
the extremity of which is then subjected to a corresponding and relatively oxtensive
displacement.
This movement is utilized to operate a contact maker which opens or closes an
electric circuit and thereby works an electric bell or other signal.
In order to preserve the sensitiveness of this apparatus it is necessary to take
the precaution of interposing a temperature compensator in the passage for the
liquid because the liquid contracts to a much greater extent than the case or tubes
and the diaphragm placed under the rail thereby becomes depressed to an extent
which prejudices the action of the apparatus.
Any suitable description of compensator may be employed, for example a
chamber of a metal such as zinc which expands and contracts rapidly with changes
of temperature may be placed in the passage for the liquid a block or mass of a
material such as marble, earthenware, glass, porcelain and the like not subject to
rapid expansion or contraction being placed inside this chamber so as to fill it
almost entirely only leaving space enough for an extremely thin film of liquid
between it and the sides of the chamber. The relative dimensions of the parts
may readily be calculated so as to render the action of the apparatus unaffected by
changes of temperature.
I JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention which has been com- 3
municated to me from abroad by Henri Lebasteur and Messrs Mignon and Rouart
of Paris in the Republic of France Engineers and in what manner the same is to
be performed to be particularly described and ascertained in and by the following
statement:
This Invention relates to an apparatus for indicating automatically and at a 3
distance the passage of Trains over the part of the line. or track to which the said
apparatus is applied. The object of the Invention is to enable a Train on passing

page_text: over any point on a Railway to operate an apparatus which indicates or records
the passage of the train at the point of passage and also notifies or signals the same
at any other or distant point on the line. Numerous attempts have been made to
effect this but without success, the apparatus as heretofore constructed being liable
when in use to become rapidly deteriorated and rendered incapable of acting with
the requisite precision.
"
The apparatus forming the object of this Invention is based upon an entirely
novel application of a known principle and acts with that degree of precision
which has hitherto been sought without success.-When a train is passing over a
Railway rail supported on chairs, the rail bends between the chairs or points of
support under the weight of the vehicles, and although the extent of this deflec-
tion is very slight, it is nevertheless sufficient to actuate an apparatus possessing
the requisite sensitiveness. These deflections of the rail are utilized according to
this Invention for operating an apparatus, which gives the desired signals or
indications.
And in order that the said Invention may be fully understood I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several figures on the annexed Sheet of Drawings the same letters of reference
indicating corresponding parts in all the figures.
Figures 1 and 2 of the accompanying drawings represent in side elevation and
plan respectively an example of an apparatus constructed according to this Inven-
tion, and Figures 3, 4 and 5 represent details and modifications hereinafter
explained.
A, Figures 1 and 2 is the rail, under which is placed a block C of cast iron or
the like containing a cavity or chamber ƒ, shewn in the section, Figure 3, covered
by a thin diaphragm ƒ¹ of thin brass or other flexible material joined at its edges
to the block C.-The chamber f, one side of which is constituted by the flexible
diaphragm f¹, is filled with an incongealable liquid and communicates through a
pipe g, with the tube of a Bourdon or other manometer or pressure gauge,
shewn at h.
The joint between the edges of the diaphragm f, and the block C may be made
with screws or by fixing the edges of the diaphragm, as indicated in Figure 3 or in
any other suitable manner. This diaphragm being composed of a single sheet of
metal is liable to wear out rapidly at the edges and is therefore preferably
strengthened at this part by the application of several rings or washers f³,-
(figure 3,) of different widths forming a species of spring. A block or plunger e, of
steel, for example, rests upon the diaphragm f, as shewn in figure 3, and the
block C, is supported on an inverted or other rigid support B, bolted to the rail A
in such a position that the block C, may be readily adjusted, in such a manner as
to bring the plunger, e, into contact with the underside of the rail A by means of a
wedge or incline d operated by a screw d¹ as indicated in Figure 1 or preferably by
means of two inclines or wedges d³ arranged as shown in Figure 3.
The apparatus being thus adjusted so as to place the liquid in the chamber f
under pressure every deflection of the rail A is transmitted through the diaphragm ƒº¹
to the liquid contained in the chamber f. The pressure thus exerted upon the
liquid acts upon the tube of the Bourdon pressure gauge or other manometer in
such a manner that a slight deflection of say about one twenty fifth of an inch in
the rail A. causes the extremity of the manometer tube to be displaced by upwards
of ten times that amount.
This mechanical movement is utilised to control or operate any suitable indica-
ting or signalling devices by any suitable means such as a contact maker which
opens or closes an electric circuit and thereby works an electric bell or other signal
at a distance.
In order to preserve the sensitiveness of this apparatus it is necessary to take
the precaution of interposing a device for compensating for variations of temperature
in the passage for the liquid because the liquid is more sensitive to variations of
temperature than the case or tubes and the pressure beneath the diaphragm f¹ is

page_text: consequently liable to vary to an extent which would affect the precision of the
apparatus.
For
Any suitable description of compensater may be employed for this purpose.
example a chamber k of a metal such as zinc which expands and contracts rapidly
with the changes of temperature may he placed in the passage for the liquid as
shewn in the drawing a block or mass k' of a material such as marble, earthenware,
glass, porcelain and the like not subject to rapid expansion or contraction being
placed inside this chamber so as to fill it almost entirely only leaving space enough
for an extremely thin film of liquid between it and the sides of the chamber as
shewn in Figure 4.
Figure 5 illustrates another arrangement for obtaining the same result consisting
in connecting the ebonito key or lever acted on by the extremity of the manometer
tube to a second manometer tube h¹ similar to the tube hand communicating
through a tube g¹ of the same length and diameter as the tube g with a chamber g
formed in the block Cand of the same capacity as the chamber f. The chamber g³
and tube g¹ being filled with the same liquid as the chamber f and tube g any
variations in the temperature having the effect of modifying the opening or
curvature of the manometer coil or tube / also affects to the same extent the
opening or curvature of the compensating tube h¹ so that the relative portions of
the extremities of the former tubé and the key or lever remain the same. By
those means the relative dimensions of the parts may readily be calculated or
adjusted so as to render the action of the apparatus unaffected by changes of
temperature.
Having now particularly described and ascertained the nature of the said
Invention and in what manner the same is to be performed I declare that what
I claim is
First. Means for automatically indicating or signalling the passage of trains on
railways the said means being operated by the bending or deflection of a rail
during the passage of a train or vehicle thereover substantially as herein before
described.
Second. The arrangements or combinations of parts forming the improved
apparatus for transmitting by fluid pressure to a signalling or indicating device
the movement due to the bending or deflection of a rail under the passage of a
train or vehicle substantially as hereinbefore described and illustrated in the
accompanying drawings.
DALL
1100K