ROLLING STOOK OF RAILWAYS
Year: 1868

page_text: LETTERS PATENT to Thomas Claxton Fidler, of Ventnor, Isle of
Wight, Civil Engineer, for the Invention of
ROLLING STOOK OF RAILWAYS."
"IMPROVEMENTS
IN
Sealed the 29th January 1869, and dated the 30th July 1868.
PROVISIONAL SPECIFICATION left by the said Thomas Claxton Fidler
at the Office of the Commissioners of Patents, with his Petition,
on the 30th July 1868.
I, THOMAS CLAXTON FIDLER, of Ventnor, Isle of Wight, Civil
Engineer, do hereby declare the nature of the said Invention for "Iμ-
PROVEMENTS IN ROLLING STOCK OF RAILWAYS," to be as follows:-
This Invention relates to certain improvements in the rolling stock of
railways, the object being to enable sharp curves to be traversed with
ease and safety, and to enable carriages and engines of long wheel base
to be employed on curves of ordinary radius, to avoid the lateral
slipping of wheels and the sinuous oscillations of carriages, and the
IP

page_text: consequent wear and tear and destruction of rolling stock and permanent
way, and the great increase of resistance to traction on curves.
I purpose to apply arrangements whereby each pair of wheels is
allowed free lateral play to adjust itself to the curvatures of the rails, the
axle of each pair of wheels being at the same time maintained in a
line radial to the curve traversed, whatever its radius, or at right
angles or nearly so to the rails below it. With this object each pair of
wheels is to be mounted in a separate truck (except in cases where, for
reasons hereinafter mentioned, it may be expedient to mount two or
more pairs in one truck), and any number of such trucks, not less than
and by preference three, are connected to and support one carriage or
engine frame. The main carriage frame is supported by and connected
to three trucks by one of the two following systems :-
Firstly. The carriage frame is fixed to the centre truck, of which it
forms a part or an extension, the centre axle being fixed at right angles
to its longitudinal axis, and rests near its ends upon the two end trucks,
being connected thereto by any of the methods usually employed in
swivelling trucks of that character. Each of these trucks turns hori-
zontally about a centre of motion which is situated in the axis of the
main carriage frame, and in the axis of the swivelling truck (such axis
being a centre line at right angles to the line of its axle), and equidistant
from the centre axle and from its own axle.
Secondly. The main carriage frame is swivelled by two centres near its
ends upon the two end trucks, these centres being in the axis of the main
frame and over the middle of the axle of each end truck, being connected
and supported by any of the methods usually employed in bogie trucks.
The middle truck is jointed at its two ends to the inner ends of the two
end trucks, the jointing pins being situated midway or nearly so between
the respective axles, and in the longitudinal axis of each of the three
trucks. It is intended that the middle truck shall be free to move
laterally, and in order to allow it to do so the jointing pins referred to
must have a certain amount of longitudinal play. This may be provided for
by letting the pins turn in guide blocks moving longitudinally in hori-
zontal guides fixed either at each end of the middle truck, or at the inner
ends of the end trucks; and in order to keep the middle truck up to its
position longitudinally it may either be led by a long radius link from
the main carriage frame, or by one of the end trucks, the joint between

page_text: it and that truck having no play, and all the longitudinal play being
allowed for at the other end; or it may be kept in position by springs
acting upon the two guide blocks, and pulling the middle truck with equal
tension to a position midway between them. The middle truck may
support the main frame by suspending links, which would prevent the
middle truck from tipping, or by rollers, and may be prevented from
tipping by horizontal transverse guides carried by the main frame near
the ends of the middle truck.
The first system is preferable for locomotive engines. It is intended
to space the axles equally, that is, in a three-axled carriage to
place the middle axle in the centre of the carriage frame and the end
axles at equal distances from it. Whichever system be adopted for
carrying the main carriage frame, it is the object and intention of this
Invention that the three trucks under one carriage frame be so con-
nected together by linkwork, wheelwork, or otherwise that if the axles
are equally spaced any deflection of one end truck from the line of the
centre truck shall necessarily be accompanied by an equal deflection of
the other end truck towards the same side, and if unequally spaced that
the angular deflections of the respective trucks from the line of the
centre truck be proportional to the distance of the axles of the respective
trucks from the centre axle, so that whatever may be the lateral
position of the three pairs of wheels the axes or centre lines of their
respective trucks shall form tangents to that circular curve which may
be described passing through the three points in the middle of the three
axles, and shall touch the said curve at the three points, and the axles
themselves being perpendicular to the said axes or centre lines shall
form normals or radial lines to the said circular curve. Consequently
whenever the carriage is upon rails laid to a continuous curve of any
radius for the whole length of the carriage all the axles of the carriage
are maintained at right angles to the rails, the circle above mentioned
forming the centre line of the railway, and whenever the centre of the
carriage is over the point at which a curve on the railway joins a
straight line, the end axles shall be more nearly at right angles to the
rails than would be the case if the axles were fixed parallel to each
other; and whenever the carriage is upon rails laid to a straight line
for the whole length of the carriage all the axles shall be parallel and
at right angles to the rails. This self-adjusting property is to be given

page_text: to the trucks by one of the following or other methods. In describing
these methods it will be assumed that the carriage is upon three pairs
of wheels equally spaced, it being understood that the system may be
extended to a greater number of axles, and that when it is desired to
space the wheels unequally, the requisite proportion between the angular
motions of the trucks may be obtained by allotting the requisite pro-
portions to the different numbers of the connecting machinery.
Firstly. The requisite equality of angular motion between the two
end trucks may be obtained in carriages of either system by fixing to
the end trucks segmental arcs struck from the centre of motion of each
end truck and gearing together under the centre of the carriage, either
as toothed wheels or connected together by chains or other flexible
attachment, also levers fixed to the end trucks and united by con-
necting rods under the centre of the carriage, duplicates of which may
be arranged the reverse way so as to throw the connecting rods always
in tension.
Secondly. The requisite equality of angular motion may also be
obtained in carriages of either system by any arrangement, causing the
distance between the wheel on one side of the middle truck and the
wheels on the same side of the two end trucks to be equal, such as a
double-armed straight lever centred on the side of the middle truck, or
on the side of the main carriage frame in the middle, and its opposite
ends connected by rods one with one end truck and the other with the
other end truck both on the same side, duplicates of which may be
arranged on the other side of the carriage so as to throw the rods always
in tension.
Thirdly. The requisite equality of angular motion may be obtained
in carriages of either system by any arrangement causing the distance
of any point in the axis of one end truck (removed from the centre of
motion to a convenient length along the axis) from the axis of the
middle truck or main carriage frame to be equal to the distance of a
point similarly situated in the other end truck from the same axis, such
as bell-crank levers centred either (1st system) one on each end truck, or
(2nd system) one near each end of the main carriage frame, with their
longitudinal arms connected respectively, in the 1st case, with the ends of
the middle truck or with points near the ends of the main frame; in the
2nd case, with points on the end trucks similarly situated in both and

page_text: conveniently removed from the centres of motion or with points near the
ends of the main frame; and, in the 3rd case, with points on the end
trucks similarly situated in both and conveniently removed from the
centres of motion or with points near the ends of the middle truck, and
so connected as to allow of the necessary play in each case either by
transverse connecting rods with india-rubber springs or by pins working
in slots or otherwise, and so arranged that the angular motion of said
arms shall measure approximately the angular motion of the end trucks,
and the transverse arms of said bell cranks so connected together by
rods that any angular motion of one end truck shall be accompanied
by an equal angular motion of the other end truck towards the same
side, duplicates of which transverse arms may be arranged on the oppo-
site sides so as to throw the rods always in tension. The same object
may also be obtained in carriages of the 2nd system by shafts carried
upon the main frame parallel to its axis, and carrying at each end pinions
of equal diameter gearing into transverse racks fixed to the two ends of
the middle truck, or the racks may be fixed to the main frame, and the
shafts and pinions to the middle truck, or wheels and pitch chain may
take the place of pinions and racks.
The method I prefer is, however, to arrange two shafts parallel to the
axis of the middle truck, and carried in bearings upon it as high as
possible under the carriage floor, and at both ends of the shafts, and if
necessary forged in one piece therewith, to arrange suspending links or
arms of convenient and equal lengths, carrying at their lower ends pins
working in bearings carried by supports fixed to the main carriage frame,
and projecting downwards from it. The suspending links or arms fixed
to one shaft must be firmly fixed in the same plane, and if necessary
trussed to the shaft in the middle, and are intended at the same time to
support the main carriage frame, to keep the middle truck from tipping,
and to maintain the axis of the middle truck during its lateral motion
parallel to the axis of the carriage frame, thus securing the equality of
angular motion of the end trucks above insisted upon. This system and
that with the use of the rack and pinion may with modifications be
applied to carriages of the 1st system.
In the analisation
+

page_text: steady wheel base for the middle truck, and to avoid centreing the trucks
under the fire-box, and to give facilities for coupling wheels, to carry two
or more pairs of wheels in the middle truck; or, on 2nd system, to carry
two or more pairs of wheels in the end trucks. When this is done each
truck is treated in arranging the position of the centres of motion, and
the position and proportions of the connecting mechanism as though it
carried but one axle midway between the extreme axles which it actually
carries.
of this Invention more
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Claxton Fidler in the Great Seal Patent
Office on the 30th January 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
CLAXTON FIDLER, of Ventnor, Isle of Wight, Civil Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirtieth day of July, in the year of
our Lord One thousand eight hundred and sixty-eight, in the thirty-
second year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Thomas Claxton Fidler, Her special licence
that I, the said Thomas Claxton Fidler, my executors, administrators,
and assigns, or such others as I, the said Thomas Claxton Fidler, 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 "IMPROVEMENTS
IN ROLLING STOCK OF RAILWAYS," upon the condition (amongst others)
that I, the said Thomas Claxton Fidler, 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
said Invention, and in what manner the same was to be performed, and

page_text: 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 Thomas Claxton Fidler, do hereby
declare the nature of my said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement:-
My Invention consists of arrangements by which the main frame
of a carriage or other railway vehicle is carried upon three independent
trucks, each of which has one or more axles and pairs of wheels. The
three trucks are so connected together as to be able to adjust themselves
laterally to the curvatures of the rails, the axle of each truck being at
the same time maintained in a line radial to the curve traversed or
nearly so.
And in order that my said Invention may be properly understood
I now proceed more particularly to set forth the system, mode, or
manner in or under which the same is or may be used or practically
carried into effect, reference being had to the accompanying Drawings,
and to the letters and figures marked thereon, that is to say :-
Fig. 1 is a diagram plan of the essential parts of a carriage with
three axles equally spaced shewing the position of the various parts
when the carriage is upon a curve. a, o, b, is the centre line or axis of
one end truck; c, o, d, is the centre line of its axle; b, r, e, is the
centre line of the middle truck; f, r, g, is the centre line of its axle;
e, p, h, is the centre line of the other end truck; i, p, k, is the centre
line of its axle; c, f, i, is the line of the outer rail; d, g, k, the line
of the inner rail. The distances o b, b r, re, e p, are equal. The
three trucks are so connected together, as herein-after more particularly
described, that whatever the curve of the rails the angle a, b, e, shall
always be equal to the angle b, e, h, so that the three centre lines
a b, be, e h, always form tangents to the circular curve o, r, p, which
is the centre of the railway if the curve is continuous through the
length o, p, and is always nearly the centre of the railway, and the
three axles cd, fg, i k, being fixed at right angles to the respective
centre lines are always maintained radial to the curve. When the
main frame is mounted according to the first system of my Invention,
its centre line is at m, b, e, n, the main främe forming a continuation of

page_text: the middle truck b, e. By the second system the centre line of the main
frame is at m, o, p, n.
Fig. 2 is a side elevation, and Fig. 2a, a plan of the main frame of
a carriage or other vehicle mounted upon three trucks, according to
the first system. On these Figures similar parts are indicated by cor-
responding letters of reference, and the same principle of lettering
similar parts is observed on all the Figures relating to any particular
modification of this Invention shewn in the accompanying Sheet of
Drawings; the elevations and longitudinal sections are drawn as they
would appear when the carriages are upon a curve, and the details of
the framing and other parts are omitted for the sake of clearness.
In Figs. 2 and 2 a, f is the main frame carrying the middle axle r,
which is mounted in the ordinary way forming the middle truck of the
system; a and h are the two end trucks carrying the end axles o and p,
and connected to the main frame by the swivelling centres b and e
respectively and supporting the ends of the main frame by the rollers c, c,
and i, i, arranged radially to the centres of motion b and e respectively.
The angles a, b, e, and b, e, h, are maintained equal by the two toothed
segmental arcs s, t, of equal radius carried by the two end trucks and
gearing together under the main frame.
Fig. 3 is a plan shewing another method of maintaining this equality
of angle. The end trucks carry diagonal arms or levers m; m, and n, n,
connected diagonally the right arm of one truck with the left arm of
the other truck by connecting rods u, u; the other parts are indicated
by the letters which refer to the same parts in Figs. 2 and 2 a.
Fig. 4a is a longitudinal section, and Fig. 4 a plan shewing another
method of maintaining this equality of angle.
The end trucks carry
segmental racks q, q, at their outer ends of equal radius, and two
conical pinions x, x, of equal diameter are keyed to the same shaft w,
carried longitudinally in the middle of the main frame by bearings y, y,
and gear into the said segmental conical racks in the ordinary manner
of bevel gearing; the other parts are indicated by the letters which refer
to the same parts in Figs. 2 and 2a.
Fig. 5 is a side elevation, and Fig. 5 a, a plan shewing a method of
extending the system to the wheels of the adjacent carriages in a train.
f is the main frame, and f¹ the half frame of an adjacent carriage or
other vehicle; r and r¹ are the middle axles of the respective carriages;

page_text: a and h are the two end trucks, and a¹ the corresponding end truck of
the adjacent carriage; o, p, and o' are the respective end axles, and b, e,
and 6' are the respective centres connecting the end trucks with the
main frames. The ends of the frames are supported as before by the
rollers c c, ii, and c' c¹. The end truck and the adjacent end truck
a¹ of the next carriage are brought close together, and the buffers d, d,
and k, k, are pressed nearly home, the buffing springs of one truck
being slacked out by the screw t to allow the coupling of the carriages
to be effected, so that the two end trucks h and a form one nearly
rigid truck, and their centre lines are maintained nearly in one straight
line e, b. The main frames f and f¹ of the two adjacent carriages are
connected by the pin u, and this connection maintains the angles b, e, b¹,
equal to the angle e, b¹, r, in the same way as the toothed segments
in Fig. 2a, the longitudinal play being taken up by the small amount
of play left to the buffers d, d, and k, k, so that the centre line e, b¹,
forms a tangent to the circular curve at the point w midway between
the centres e and b¹.
Fig. 6 is a half longitudinal section, and Fig. 6a, a half side elevation
of a carriage or other vehicle constructed according to the second
system of this Invention. Fig. 7 is a half plan of the independent
wheel trucks, and 7 a, a half plan of the main frame of the same.
Fig. 8 is a cross section of the same taken through the bogie pin of one
end truck, and Fig. 8 a, a cross section shewing the connection of the
middle truck with the main frame and with the end truck. In all
these Figures f indicates the main frame which rests by the sockets c, c,
upon the bogie pins g, g, of the two end trucks and by the four brackets
d, d, d, upon pins carried at the lower ends of four suspending
links n attached to the middle truck. a and are the two end trucks
supporting the ends of the main frame by the bogie pins g, which are
situated over the centres of their respective axles o and p. The main
frame may also have a side bearing upon the end trucks by means of
rollers, which are omitted in the Drawing for the sake of clearness.
The end trucks are connected to the middle truck by the joints b and e,
which may be universal joints. The middle truck is connected to the
main frame by two pairs of suspending links n, each pair being firmly
keyed on the opposite ends of a shaft m or forged in one with it; these
shafts are carried in bearings s on the middle truck. The object of

page_text: these suspending links and shafts is fourfold, 1st, to transmit a portion
of the weight of the main frame and load to the middle truck, while
allowing the middle truck to move laterally under the main frame;
2nd, to keep the middle truck from tipping; 3rd, to preserve the middle
truck always parallel to the main frame, thereby maintaining the angle
a, b, e, equal to the angle b, e, h; and 4th, by its oblique action to give
the middle truck a tendency to return to its central position. The
bogie connection of the end trucks may be of any description, but I
prefer to form the bogie pin as a spherical segment convex upwards,
the centre of the sphere being situated at a point as much below the
level of the joints b and e as the lengths of the suspending links n
from centre to centre, so that as the joint b moves with the rest of
the middle truck in a circular are of a radius equal to that length
the distance from the centre of the said sphere to the joint b does
not alter during the motion of the middle truck.
Fig. 9 is a cross section shewing another form of the suspending
links. n, n, are the suspending links or arms which are keyed to the
shafts m at their upper ends as before, and at their lower ends carry
two pins k, k, working in slots in the brackets d, the object being to
give the truck a greater stability in its middle position. In all the
Drawings each truck is shewn as having only one axle, but any of the
trucks may also have two or more axles, and where this is done the
distance from the centre of the wheel base of any truck to its connection
with the next truck is made equal to the distance from that connection
to the axle of that truck or to the centre of its wheel base. In Figs. 5
and 5a, the two trucks h and a being rigidly connected are regarded
as one truck having two axles, and the distance r, e, is equal to the
distance from e to a point w midway between the axles p and o' or
nearly so. In all the Drawings the distances of the end axles from the
middle axle are equal, but the distances may also be unequal, and
where this is done the connection between any two adjacent trucks is
placed midway between their axles, that is, the length o, b, is equal
to the length b, r, and the length 1, e, is equal to the length e, p; but
the length o, r, may be greater or less than r, p, and in this case the
supplement of the angle a, b, e, is made to bear the same proportion
to the supplement of the angle b, e, h, that the length o, r, bears to the
length, p. This may be done in Figs. 2 and 2 a, by altering the radii
of the toothed segments s and t, and in Fig. 3 by altering the lengths

page_text: of the arms m and n, and in Figs. 4 and 4a by altering the radii of
the pinions, and of the racks or segments q, and in Figs. 5 and 5 a by
altering the lengths e, u, and u, b', and in carriages of the second system
by altering the lengths of the suspending links of each pair. Moreover
as the only consequence of departing slightly from the proportions as
above determined would be to throw some of the axles slightly out
of the radial position, and as it may be advantageous for other reasons
to choose other proportions, therefore I do not confine myself to these
or any proportions or dimensions; and further I do not confine myself
to any particular form of buffing or draw apparatus or coupling which
may be carried either upon the swivelling trucks or on the main frame,
nor to any particular form of truck which may have inside or outside
bearings, nor to any particular form of swivelling or bogie pins or rollers,
and the rollers may either be carried upon the swivelling trucks or upon
the main frame.
Having now described the nature of my said Invention, and in what
manner the same is to be carried into practical effect, I wish it to be
understood that what I claim as novel and original, and therefore desire
to be secured to me by the herein in part recited Letters Patent is,-
1st. The method of enabling vehicles to pass round sharp curves and
of maintaining their axles radial to the curve or nearly so by mounting
the main frame of a carriage or other vehicle upon one or more axles in
the centre, and upon two swivelling trucks each containing one or more
axles, and so connected as to deflect in lines tangential to the curve, as
illustrated at Figs. 2, 2 a, 3, 4, and 4 a of the annexed Drawings.
2ndly. The method of connecting the swivelling end trucks of two
adjacent vehicles in a train to form one nearly rigid truck, and of con-
necting the ends of the main frames of the said vehicles as illustrated
at Figs. 5 and 5 a of the annexed Drawings.
3rdly. The method of swivelling the main frame of a carriage or
other vehicle upon two end trucks each having one or more axles, and
connected at their inner ends to a middle truck moving transversely
under the middle of the main frame, and also having one or more
axles, as illustrated in Figs. 6 to 9 inclusive of the annexed Drawings.
4thly. The method of maintaining such a middle truck during its
transverse motion parallel to the main frame and in a horizontal
position, and of supporting the main frame by means of swinging

page_text: links or arms fixed to the ends of shafts carried by the middle truck,
as illustrated in Figs. 6 to 9 inclusive of the annexed Drawings, all
substantially as herein specified.
In witness whereof, I, the said Thomas Claxton Fidler, have here-
unto set my hand and seal, this Twenty-first day of January,
in the year of our Lord One thousand eight hundred and sixty-
nine.
Witness,
ALEX
PRINCE,
Office for Patents,
4, Trafalgar Square,
Charing Cross.
T. CLAXTON FIDLER. (L.S.)