IMPROVEMENTS IN RAILWAY CROSSINGS
Year: 1858

page_text: LETTERS PATENT to William Clark, of 53, Chancery Lane, in the
County of Middlesex, Engineer and Patent Agent, for the Invention of
"IMPROVEMENTS IN RAILWAY CROSSINGS."-A communication from Emile
Poiret.
Sealed the 19th October 1858, and dated the 28th April 1858.
PROVISIONAL SPECIFICATION left by the said William Clark at the
Office of the Commissioners of Patents, with his Petition, on the 28th
April 1858.
I, WILLIAM CLARK, of 53, Chancery Lane, in the County of Middlesex,
Engineer and Patent Agent, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN RAILWAY CROSSINGS," to be as follows:-
This apparatus consists like ordinary railway crossings of two parts, each
of which is composed of,-
First, two moveable rails, a, b, and c, d, firmly connected together by bolts
m, x, n, z, &c., and having one of their extremities jointed in a chair b, d,
termed the "switch heel chair;" these two rails are substituted for the fixed
rail and switch of ordinary railway crossings, and serve to guide the carriages
on to either of the two lines placed in communication by those parts.
Secondly, a flat or other formed fixed bar of iron raised above the moveable
rails; it is connected at each of its extremities to two ends of ordinary rails.
e, g, f, h, which are also fixed, and form with them a single rail and likewise

page_text: a counter rail; this arrangement is intended to allow the inside moveable rail c, d,
to pass under this counter rail.
Thirdly, supports or chairs a', b', c', &c., which sustain the fixed parts, and
also serve to guide the moveable parts.
Fourthly, tie rods m, m, n, n, serving to render the two pairs of twin rails
firm and simultaneous in their movement, and also to maintain a constant
distance between them.
Fifthly, and lastly, a rod a, v, fixed at one extremity to the moveable rails
which it serves to actuate, and at the other extremity to a counterpoised lever
exactly similar to those used for ordinary crossings.
The most serious defect in crossings hitherto employed is the danger they
present when crossed by a carriage entering at the points, and especially by a
whole train. The improved apparatus which I propose offers, on the contrary,
perfect security in whichever direction the crossing may be traversed.
When a carriage enters the crossing at the heel of the switches, the flanges-
of the wheels interpose between the fixed counter rail f, h, and the inside
moveable rail, and will always compel this latter to communicate with the
single line; the action of this apparatus is identical with the ordinary
crossings.
When the vehicle enters at the point end of the switches, it is also guided by
the fixed counter sails, which preserve a distance of an inch and a quarter, or
more if desired, between the flange and the extremity of the moveable rail.
From this first condition it results that any body of an inch and a quarter.
or more.in size held between the outside moveable rail and the chairs, would
not disturb the parts of the crossing, and that owing to this circumstance and
to the small surfaces of the parts of this apparatus and of the chairs, this
apparatus could be worked under snow, whereas in such cases with the
ordinary crossings the line would be deranged in its working; moreover a
wheel once entering its flange between the fixed counter rail and the inside
moveable rail (see section C, D,) is held in proper position, and the wheel
following next necessarily goes on to the same line, although a force should
tend to change the action of the apparatus; such force applied to change the
apparatus occasions frequent accidents with apparatus or crossings hitherto
employed.
Supposing that by reason of some circumstance the action is imperfect, that
is to say, that neither of the two moveable rails is in communication with the
single line, the two inside rails will be then opposite the space which separates
the fixed counter rail, and that the flanges will ascend on to the inside rails,
but the counter rails being at a higher elevation will not cease to direct the

page_text: carriage, and in rolling one of the flanges will fall between the counter rail
and the inside moveable rail, and thus restore the apparatus to its normal
state before the wheels following arrive to be held therein. It can then be
said that with this new apparatus there is little or no chance of derangement of
the rails at the crossing at those points.
Besides the chief advantages which I have mentioned, this improved
crossing presents those of strength and consequently of economy in repairs..
It is known that the tapered switches heretofore employed wear rapidly, and
are soon unfit for use, especially when placed on curved or much frequented:
lines, which is the case on many lines; hence they require, to be renewed nearly
every year, and owing to the high price of this piece, considerable expense is
incurred for repairs. The cost price of this new apparatus is about the same
as the ordinary ones; the counter rails increase the expense, but this expense is.
diminished by the cost saved in preparing. the switches,
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Clark in the Great Seal Patent Office on the
27th October 1858.
. TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
CLARK, of 53, Chancery Lane, in the County of Middlesex, Engineer and
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-eighth day of April, in the year of our
Lord One thousand eight hundred and fifty-eight, in the twenty-first year of
Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said William Clark, Her special licence that I, the said
William Clark, my executors, administrators, and assigns, or such others
as I, the said William Clark, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and at all
times thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVE-
MENTS IN RAILWAY CROSSINGS," a communication from Emile Poiret, upon the
condition (amongst others) that I, the said William Clark, my executors or
administrators, by an instrument in writing under my, or their, or one of their
hands and seals, should particularly describe and ascertain the nature of the

page_text: said Invention, and in what manner the same was to be performed, and cause
the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Clark, do hereby declare the
nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement, reference being had to the Sheet of Drawings hereunto annexed,
and to the letters and figures marked thereon (that is to say) :-
This Invention consists in effecting the changing of the line of way at the
points or crossings of railways with the greatest certainty of its correct
performance. This new apparatus is composed like ordinary crossings of two
parts represented in the Drawings annexed.
Fig. 1 represents a longitudinal elevation of the apparatus complete; Fig. 2
shows a plan of the same apparatus; Fig. 3 shows a transverse section on the
line C, D. The same letters of reference indicate like parts where they recur
in all the Figures. Each part of the crossing is .composed, 1st, of two
movable rails a, b, and c, d, firmly connected together by bolts m, x, z, &c.,
and having one of their extremities jointed in a chair b, d, termed the switch or
point heel chair; these two rails are substituted for the fixed rail and switch
of ordinary railway crossings, and serve to guide the carriages at will on to
either of the two lines placed in communication by these parts. 2ndly, a flat
or other formed fixed bar of iron e, f, raised about half an inch above the
movable rails; it is connected at each of its extremities to two ends of ordinary
rails e, g, f, h, which are also fixed and form with them a single rail, and
likewise a counter rail; this arrangement is intended to allow the inside
movable rail c, d, to pass under the counter rail. 3rdly, supports or chairs
a', b, c, d', &c., which sustain the fixed parts, and also serve to guide the
movable parts. 4thly, the rods or stretchers m, m, n, n, serving to render
the two parts of the twin rails simultaneous in their movement, and also to
maintain a constant distance between them. 5thly and lastly, a rod x, v, fixed
at one extremity to the movable rails, which it serves to actuate, and at the
other extremity to a counterpoised lever, exactly similar to those used for
ordinary crossings.
The most serious defect in crossings hitherto employed is the danger they
present when crossed by a carriage entering on the points, and especially by a
whole train. The improved apparatus which I propose, on the contrary, offers
perfect security in whichever direction the crossing may be traversed. When
a carriage enters the crossing at the heel of the switches, the flanges of the
wheels interpose between the fixed counter rail f, h, and the inside movable.

page_text: rail, and will always compel this latter to communicate with the only line of
way;
the action of this apparatus is identical with the ordinary crossings.
When the vehicle enters at the point end of the switches, it is also guided
by the fixed counter rails, which preserve a distance of an inch and a quarter, or
more if desired, between the flange and the extremity of the movable rail.
From this first condition it results that any foreign body of an inch and a
quarter or more in size, held between the outside movable rails and the chairs,
would not disturb the parts of the crossing, and that owing to this circumstance
and to the small surfaces of the jaws of the chairs, this apparatus could be
worked under snow, whereas in such cases with the ordinary crossings the
line would be deranged in its working, moreover a wheel once entering its
flange between the fixed counter rail and the inside movable rail, (see section
C, D,) is held in proper position, and the wheel following next necessarily
goes on to the same line, although a forcé should tend to change the action of
the apparatus. Such force applied to change the apparatus occasions frequent
accidents with apparatus or crossings hitherto employed.
Supposing that by reason of some circumstance the action is imperfect, that
is to say, that neither of the two movable rails is in communication with the
single line, the two inside rails will be then opposite the space which separates
the rail of the single line from the fixed counter rail, and that the flanges will
ascend on to the inside rails, but the counter rails being at a higher elevation
(about one inch and three quarters), will not cease to direct the carriage, and
in rolling, one of the flanges will come between the counter rail and the inside
movable rail, and thus restore the apparatus to its normal state, before the
wheels following arrive to be held therein. It can then be said that with this
new apparatus there is little or no chance of derangement of the rails at the
crossings, or of the carriages running off.
Besides the chief advantages which I have mentioned, this improved
crossing presents those of strength, and consequently of economy in repairs.
It is known that the tapered switches heretofore employed wear rapidly and
are soon unfit for use, especially when placed on curved and much frequented
lines, which is the case on many lines; hence they require to be renewed nearly
every year, and owing to the high price of this piece, considerable expence is
incurred for repairs. The cost price of this apparatus is about the same
as the ordinary crossings, the counter rails increase the expence, but this
expence is diminished by the cost saved in planing and preparing the switches.
Fig. 4 represents a modification of the foregoing in plan, and Fig. 5 an
elevation, showing a crossing with a triple change of line. This arrangement
is in principle identical with the crossings described, from which it differs only,

page_text: 1st, in its being composed of three twin rails coupled together instead of two,
otherwise termed three movable rails, which are to be used as is well understood
when the apparatus is to unite three lines of way. 2ndly, the raised counter
rail, consisting of a bar of iron, is lengthened towards f, which is necessitated by
the increased length of the movable rails, the interior rail requiring to engage
with the counter rail nearly its whole length on this side. 3rdly, the counter
rail instead of being supported by each chair a', b', c', d', is not supported by
the chains 6 and d', so that the span is doubled at that part; to diminish the
effect of this increase of the span, the cross section of the counter rail is
increased to two and a half inches by one and a quarter inch. This arrange-
ment is required on account of the movable rail passing under the counter
rail to a great length, which renders it too difficult to support the latter by the
chair b'; experience has also shown that this arrangement can be adopted
without inconvenience. In any case it is possible if necessary to support the
counter rail at each chair. 4thly, the working gear of the apparatus consists of
a particular arrangement to effect the movement of the points in two stages,
so as to put it in communication with the middle line. This apparatus is
simply composed of a lever i, k, each extremity of which is worked by an
ordinary counterbalance lever in such manner that there is a combination of
two levers, as used in "Wild's" three-way crossing.
It will be perfectly understood that at each movement of the lever the
point or axis of lever i, k, will move a distance equal to half of the whole
distance moved. This arrangement is advantageous in being able to commence
working by either of the levers, they being in the same position; the change
in consequence is to the extremity of its course.
This apparatus, as will be readily understood, renders this crossing is
absolutely secure only at the side rails, the middle way having no counter
rails to insure its action. This difficulty may be met by adjusting the counter-
weights of the two levers in a contrary way, so that the middle way will remain
open.
Having described the nature of the Invention, and the manner of performing
the same, I declare that what I claim as the Invention to be secured by the
herein-before in part recited Letters Patent is, the railway crossings herein-
before described, characterized, 1st, by two moveable rails a, b, c, d, fixed the
one to the other, and jointed to the heel chairs b, d, those two rails replacing
the fixed rail and the switch of the ordinary crossings. 2ndly, by a bar of
iron e, f, raised above the moveable rails & connected at the two extremities
to two ends of the ordinary fixed rails e, g, f, h, this bar of iron allowing one
of the rails to lodge under the counter rail. 3rdly, by the chairs a', b', c', d',

page_text: which sustain the fixed parts of the apparatus, and serve to guide the moveable
parts. 4thly, by the rods or stretchers m, n, connecting rigidly the two switch
or change rails. 5th, by the manovering rod x, v.
I further claim the modified arrangement represented by the triple crossing
herein-before described.
In witness whereof, I, the said William Clark, have hereunto set my
hand & seal, this Twenty-sixth day of October, in the year of our Lord
One thousand eight hundred and fifty-eight.
Witness,
W. G. E. SWINNOCK,
53, Chancery Lane.
W. CLARK. (L.S.)