Improvements in Electrical Train Signalling Apparatus.
Year: 1885

page_text: Improvements in Electrical Train Signalling Apparatus.
I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of
53, Chancery Lane, in the County of Middlesex, Fellow of the Institute of
Patent Agents, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN ELECTRICAL TRAIN SIGNALLING APPARATUS" a communication to me
from abroad by Eugène Jacques Jérôme de Baillehache, of 54 Rue Ampère, Paris
France, Electrical Engineer to be as follows:-
This Invention relates to a system of automatic electric train signalling for
railways and steam or other tramways whereby the train is caused to signal its
whereabouts to the station. This is effected by insulating one or more sections of
rail and connecting the same with a line wire so that when the train passes over
this insulated section, the circuit will be closed between the insulated and
uninsulated rails by the wheels of the train.
In order that the Invention may be more readily understood I will proceed to
describe it with reference to the accompanying drawings which show some
examples of the invention.
Figure 1 is a diaphragm showing the line as arranged at the approach to a
station. Figures 2 and 3 are diagrams of modifications. Figure 4 shows in
vertical section, the method of insulating the rail at fishplate. The same letters of
reference indicate the same parts in all the figures. Referring to figure 1 it will be
seen that a train or engine passing from A to B or from B to A will close the
circuit in passing over the insulated rail section C and sound the gong S, this rail
section being connected to the line wire L by the wire D and gong S being to
earth through the wire E, whilst the other rail F is uninsulated. The circuit will
therefore be closed all the time a train is passing over the insulated section x y and
the train is thus signalled at the station.
If several insulated rail sections at certain distances apart on the same line be
thus connected to one or more line wires, each closure of the circuit by the passage
of a train may be registered at the station by means of a Bréguet or other step by
step instrument, whereby the position of the train on the line may be indicated.
This may also be indicated graphically by a morse printer the speed of the train
being also indicated by the length of the dashes.
This arrangement is represented diagrammatically in figure 2 in which there are
two insulated sections C C. S is a Bréguet or other instrument whereby the
position of the train is indicated as it passes successively over the insulated rail
sections x, y, x, y. L is the line wire D, D¹ the conducting wires, E the earth
wire and P the local battery.
To prevent a false signal given by an accidental closure of the circuit by an iron
tool being placed upon the adjacent ends of the insulated and uninsulated sections

page_text: of the rail thus putting the former to earth, the arrangement shown in Figure 3
may be adopted, in which the rail sections C¹ C adjacent to the insulated
section C are also insulated so that the section C can only be put to earth by the
passing of a train connecting it with opposite uninsulated rail F.
This improved system of signalling is also adapted for establishing alarm posts
along a railway as represented in figure 2 in which M is a wire connecting L with
a contact m placed on a telegraph pole for example and N is a second wire con-
necting a second contact n to earth. By interposing an electro-magnetic apparatus
of any kind between the studs m, n, the station may be communicated with. This
system of alarm posts entirely obviates the necessity of employing and maintaining
special" batteries either at the posts or in the guard's van. If the connection D
between the insulated rail section and the line wire be formed of two conductors
enclosed in the same lead sheathing, one branch only would be secured beneath the
head of the fish bolt while the other and free end would serve for connection with
the line, the earth connection being made by another wire with the noninsulated
rails.
The rail may be insulated in many ways but the method I prefer to employ is
shown in figure 4 in which a is the rail laid on a sleeper b which is well coated
with tar or equivalent material. To insulate the rail, a layer of felt, leather or
other tar covered material of suitable thickness is first placed upon the sleeper, and
between the fish plates d and the rail are inserted strips of leather or other
insulating material e, the edges of which project on all sides, beyond the fish plate.
The strips e are perforated for the bolts f to pass through, the latter being insulated
from the rail by a sheathing g and also from the fish plate by washers h also of
leather, india rubber or other insulating material; the washers may however be
replaced by strips perforated for the fish plate bolts to pass through. It is
preferred to employ bolts screw threaded at the nut end only, on the inside of the
line. The spike i is insulated from the sleeper b and rail, by a sheath k and
washer or plate b. Where the rails are supported by chairs the insulation of the
latter is effected in the same manner. At the two extremities of the insulated rail
section, that is to say at the points x, y of the diagrams, Figures 1 and 2, are placed
two thicknesses of tarred leather or felt which thus insulate the said rail section
from the adjoining noninsulated rails.
The insulated rail is perforated at a suitable point of its length to receive a bolt
which should be bright when inserted in order to obtain a good contact with the
rail, and connect the latter with the line by means of the wire D figure 1. This
bolt may be nickel coated at the points of contact, or it may be made of copper with
silvered contacts. The bolt is prevented from loosening by a lock nut.
The leathers, bolts, fishplates, spikes, holes and other connections are all insulated
with tar as are also the chairs supporting the insulated rail. Perfect insulation is
ensured by the above arrangements as the current cannot escape at the ends of the
short length of insulated line, owing to the interposition of the leather between the
adjacent ends as described and the four insulating coverings of the rail, fish plates
and bolts must all be destroyed before the rail can get to earth. The rail may also
'be tarred throughout its length except on the surface upon which the wheels run
and it may be laid upon tarred longitudinal sleepers or partly let into a well tarred
groove to insulate it from the ballast, which is however a poor conductor. In order
to prevent water from remaining on the line, the ballast may be dispensed with,
and the sleepers and cross ties may be laid upon a bed of cement, asphalt, bitumen
or other non conducting material.

page_text: Improvements in Electrical Train-signalling Apparatus.
I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of
53, Chancery Lane, in the County of Middlesex, Fellow of the Institute of Patent.
Agents, do hereby declare the nature of this Invention (a communication to me
from abroad by Eugène Jacques Jérôme de Baillehache, of 54 Rue Ampère, Paris,'
France, Electrical Engineer), 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 a system of automatic electric train signalling for
railways, and steam or other Tramways, whereby the Train is caused to signal its
whereabouts to the station. This is effected by insulating one or more rails or.
contact rails and connecting the same with a line wire so that when the train passes
over this insulated section the circuit will be closed between the insulated and.
uninsulated rails by the wheels of the train.
}
In order that the Invention may be more readily understood, I will proceed to.
describe it with reference to the accompanying Drawings, which show some examples.
of the Invention.
:
Figure 1. is a diagram showing the line as arranged at the approach to a Station.
Figures 2. and 3. are diagrams of modifications.
Figure 4. shows the method of insulating the rail at a fishplate.
The same letters of reference indicate the same parts in all the Figures.
Referring to Figure 1. it will be seen that a train or engine passing from A to B,
or from B to A, will close the circuit on passing over the insulated rail or contact
rail C, and sound, the gong S, this rail section being connected to the line-wire L
by the wire D, and gong S being to earth through the wire E, whilst the other:
rail F is uninsulated. The circuit will, therefore, be closed all the time a train is
passing over the insulated section xy, and the train is thus signalled at the station.
If several insulated rail sections at certain distances.apart on the same line be thus'
connected to one, or more, line-wires, each closure of the circuit by the passage of
a train may be registered at the Station by means of a Brèguet, or other step by
step instrument; whereby the position of the train on the line may be indicated.
This may also be indicated graphically by a Morse printer, the speed of the train
being indicated by the length of the dashes.
This arrangement is represented diagramatically in Figure 2 in which there are
two insulated sections C. C. S is a Bréguet or other instrument whereby the
position of the Train is indicated as it passes successively over the insulated rail.
sections x 3, xy. L is the line wire, D D¹ the conducting wires, E the earth
wire, and P the local battery.
To prevent a false signal, given by an accidental closure of the circuit by an iron
tool being accidentally placed on the adjacent ends of the insulated and uuinsulated.
sections of the rail thus putting the former to earth, the arrangement shown in
Figure 3. may be adopted in which the rail sections C₁ C² adjacent to the insulated:
section C are also insulated, so that the section C can only be put to earth by the
passing of a Train connecting it with the opposite uninsulated rail.F.
This improved system of signalling is also adapted for establishing alarm posts:
along a railwaycas represented in. Figure 2 in which M. is a wire connecting. L witho
;

page_text: a contact m placed on a telegraph pole, for example, and N is a second wire
connecting a second contact n to earth. By interposing an electro-magnetic
apparatus of any kind between the studs m n the station may be communicated
with. This system of alarm posts entirely obviates the necessity of employing and
maintaining special batteries either at the posts or in the guard's van. If the
connection D between the insulated rail section and the line-wire be formed of two
conductors enclosed in the same lead sheathing, one branch only would be secured
beneath the head of the fish-bolt, while the other and free end would serve for
connection with the line the earth connection being made by another wire with the
non-insulated rails.
In order that the same insulated rail may actuate several alarms, I introduce
between the battery P of the first post and its gong $ a resistance C equal to the
length of the line, which extends to the next post (see Figure 10) In this manner
it is possible, by interposing resistances equivalent to the distances between the
battery and the different posts, to act on several alarms by the same insulated rail or
contact rail,
In order to ascertain, at any moment, whether the apparatus is in proper working
order the arrangement shown, by way of example, in Figure 5 is employed; the
mode of connecting the same with the signalling apparatus being also shown. As
before explained, when a train running from A to B, or from B to A passes over
the insulated section C it places said section to earth through the line of rail F. and
sounds the gong S. To check the working of the system a separate wire R, shown
in dot and dash lines is connected to the insulated section C which wire is to earth
at T, and has, interposed in its length, a bell mechanism ✗, or a Morse key or
commutator. Thus arranged, on pressing button ✗ the circuit will be closed by the
earth between the line-wire L and wire R and gong S will be sounded. This
simple action shows;
1st That the line wire L is in good condition.
2nd That the battery is in working order.
3rd That the gong or signalling apparatus S is also working.
4th That the earth connection is also perfect, in as much as the earth connection
of the signal button ✗ is the same as that of the entire train passing over the
line.
It also shows whether the rail C is sufficiently insulated, or not, as in the latter
case the gong S would be sounded without pressing button ✗. It will thus be
seen that by the above arrangement perfect security of working is ensured,
inasmuch as at any moment by simply pressing a button, key, or commutator, may
be verified at the same time the condition of the line insulated rail, line battery
earth connection, and the gong, or other signalling apparatus. The button X, or
its equivalent, may be placed in any suitable position, such as in a gate-keeper's or
pointsman's cabin, station, etc.
The rail may be insulated in many ways, but the method I prefer to employ is
shown in Figure 4; in which a is the rail laid on a sleeper b which is well coated
with tar or equivalent material. To insulate the rail, a layer of felt, leather, or
other tar-covered material c of suitable thickness is first placed upon the sleeper;
and between the fish plates d and the rail are inserted. strips of leather or other
insulating material e the edges of which project on all sides beyond the fish plates
The slips e are perforated for the bolts f to pass through, the latter being insulated
from the rail by a sheathing g and also from the fish-plate by washers h also of
leather, india-rubber, or other insulating material; the washers may, however, be
replaced by strips perforated for the fish plate bolts to pass through. It is preferred
to employ bolts, screw-threaded at the nut end only, on the inside of the line. The
spike i is insulated from the sleeper b and rail by a sheath and washer or plate l.
Where the rails are supported by chairs the insulation of the latter is effected in
the same manner. At the two extremities of the insulated rail section, that is to
say, at the points xy of the diagrams Figures 1. and 2. are placed two thicknesses
of tarred leather, or felt, which thus insulate the said rail section from the adjoining

page_text: non-insulated rails The insulated rail is perforated at a suitable point of its
length to receive a bolt which should be bright when inserted in order to obtain a
good contact with the rail, and connect the latter with the line by means of the
wire D. Figure 1. This bolt may be nickel coated at the points of contact, or it
may be made of copper with silvered contacts. The bolt is prevented from
loosening by a lock nut. The leathers, bolts, fishplates, spikes, holes, and other
connections,, are all insulated with tar, as are also the chairs supporting the
insulated rail. Perfect insulation is insured by the above arrangements, as the
current cannot escape at the ends of the short length of insulated line owing to
the interposition of the leather between the adjacent ends as described, and the
four insulating coverings of the rail, fish plates, and bolts must all be destroyed
before the rail can get to earth. The rail may also be tarred throughout its length,
except on the surface upon which the wheels run, and it may be laid upon tarred
longitudinal sleepers, or partly let into a well-tarred groove to insulate it from the
ballast, which is however a poor conductor. In order to prevent water from
remaining on the line, the Ballast may be dispensed with, and the sleepers and
cross-ties may be laid upon a bed of asphalt, cement, bitumen or other non-
conducting material. One section of the line may also be insulated by simply
insulating the fish-plates of the extreme rails, provided that the rails be insulated
at the chairs (in the case of double-headed rails) by placing beneath them a
thickness of leather varnished, or covered with gutta percha, or other insulating
substance, such as linoleum, vulcanized vegetable fibre, Lincrusta Walton,
caoutchouc, or tarred felt. The fixing of the parts may be facilitated by preparing
the fish plates beforehand, as illustrated in face view in Figure 6, and in section in
Figure 7. These fish plates a may be provided with two kinds of bushings b and c
which are let into the fish plate, and which may also be inserted in the web of the
rail. The larger bushing 6 is made of a hard insulating material such as leather,
or compressed paper. The smaller one c serves to take the pressure of the bolts,
and is made of sheet iron or steel. The fish plate a is covered entirely with
leather, gutta percha, or other insulating material a¹ in such manner that the bolt
at its head and base will be enclosed in a casing which will prevent its communi-
cating with the metal of the fish-plate. In cases where the fish-plates would be
made of hard insulating material, such as glass, or compressed paper, the bolts
would be perfectly insulated one from the other, while the joints which connect
the two rails together end to end are insulated by the leather or gutta-percha sole
pieces.
b
It will be readily understood that a short section of rail, contact rail, or bar of
iron or steel placed at a short distance from the rail may be similarly insulated
contact being made with this contact rail as with the rail itself, the principle of
the Invention remaining always the same, namely, that of closing the electric
circuit by the wheel tyres, the metallic surface being kept constantly bright by
the passage of the trains, thus dispensing with the need of any special friction
arrangement.
Suppose a rail section or metal bar d, fixed to two or more sleepers, be placed
parallel to the rail on the outside of the line as shown in Figures 8. and 9. If
the distance between the rail and this extra rail or bar is but slight the wheel tyre
will touch this contact rail, and if the latter be insulated, that is to say separated
from the rail by a strip of leather, or gutta percha h, the cable or line wire may be
connected at any point by means of a terminal, or copper bolt, for example The
wheel-tyre would be to earth through one or other of the main rails which it
would, in this case, be unnecessary to insulate, except it is desired to have two
distinct lines. In order to protect the contact rail d from concussion, during the
passage of the train, its upper surface is made slightly curved, the curve being a
little higher than the rail (about two millimetres) at its middle point while still
following the same gradient as the line, this contact rail d having a tendency to
be depressed by the weight of a train passing over it. In order to limit the play
of the contact rail d, brackets.g are fixed upon the rail e by a bolt, or bolts, f, and

page_text: made of corresponding form at the base to the foot of the rail against which they.
bear. The brackets are insulated from the contact-rail by strips of leather, and
gutta-perchal, or other insulating material, as shown. When the rail e is deflected
by the weight of the train the brackets g partake in its downward movement and
also rise with it when the pressure is removed, thereby causing the contact rail
also to resume its original position so as to insure a good contact. It will be seen
that this arrangement enables a train to be signalled with certainty, the contact
of the contact rail being kept continually clean by the wheel-tyres which is an
essential feature of the Invention.
In order to facilitate the fitting of the contact rail d it is bent at each end, first
downwards, and then horizontally as shown in Figure 8. The horizontal limbs
may be fixed directly by means of screws, but to ensure more perfect insulation,
the contact rail, clamps i of the form represented are placed on each side of or
astride of, the limbs, the edges of which are rounded off at the points where they
rest on said limbs. Their surfaces are insulated from the limb by varnished
leather, gutta percha, or other compressible insulating material, the screw spikes
being, in this manner, prevented from coming in direct contact with the rail. In
order to still further improve the insulation, a thickness of leather . either
varnished, or coated with gutta percha or other insulating material, may also be
applied on the tarred sleeper e, as in the case of the brackets g, while the parallel
bar itself is separated from the rail to which it is attached by a thickness of
leather h, either varuished, or coated with gutta percha. The leather which is
inserted between the bracket and the contact-rail may be secured by countersunk
screws inserted from below in the contact rail d. A contact-rail or bar of a
length of from ninety centimetres to one nietre is sufficient to establish contact and
sound the gong at the post, or actuate a relay which closes the local current of a
trembler placed in the pointsman's or gatekeeper's cabin The contact rail may,
however, be of greater length in which case the number of brackets y would be
increased. To insure certainty in the electric action two contact rails are necessary
one beside each rail, owing to the clearance between the wheels and rails, and to
the fact that the wheel flanges bear, at one time, against the one rail, and at other.
times, against the other Although it would be simpler to insulate a length of one
of the rails instead of two contact-rails it will be seen that the principle of the
Invention is the same as in both cases it is the wheel-tyre which closes the circuit
to earth without the use of a special friction contact, and the contact surface being
kept bright by the cleaning action of the wheel itself. This system of insulated
rails and contact rails acts perfectly even in snow, as the polishing of the metallic
surface is much more intimately effected by the wheel of a train than by the
pressure of a brush, or other rubber. Although tarred leather or felt has been
mentioned as the insulating material preferably employed, artificial leather soft, or
hard, india-rubber or other nonconducting material may be substituted therefor, or
the surfaces may be enamelled etc.. It is best to employ Stockholm tar for the
purpose but mineral tar gives equally good results.
"
Any kind of visible or audible signals may be placed in the circuit closed
automatically by the passage of the train, and more particularly electric lighting
apparatus, which might be disposed at stations, junctions, level crossings, or at
other points of the line, which apparatus, by becoming automatically lighted would
announce the arrival of the train. The above arrangements are those that have
been employed in the application of this system on different French Railways and
more particularly on the Western Eastern and Orleans Lines as well as on the
State Railways. The application of the insulated rail on the Circular Railways at
the Stations of Courcelles-Ceinture, and L'Avenue de Clichy have formed the
subject of very eulogistic reports from the Engineers, who have shown that the
insulation remained the same after the passage of more than twenty-five thousand
trains and engines, and it has been proved that notwithstanding snow, heavy rains;
and every variation of temperature, it is impossible for the system. to get out of
working order, inasmuch as no expense has ever been incurred hitherto on. these

page_text: lines in which the system has been applied in all the various ways hereinbefore
described, including level crossings, branches, points, automatic block system
etc, etc.
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
1st A system of automatic electric train signalling for railways and tramways
consisting in the combination of one or more insulated rails or contact rails in
electrical communication with the line-wire, of a line wire L, local battery P, and a
gong S, or other signalling apparatus actuated when the circuit is closed by the
passage of a train the wheels of which connect the insulated rail to the rail in
communication with the earth without the use of frictional contact devices as
herein before described and represented in the accompanying Drawings.
2nd In a system of automatic electric train signalling for Railways and tram-
ways as described the application of the checking arrangement, consisting in the
combination of the conducting wire R one end of which is in communication with
the insulated rail, and the other end with a contact X; in such manner that by
closing this contact the circuit is closed between the line wire L and the wire R
and the signal is sounded as herein before described with reference to Figure 5 of
the Drawings,
3rd In a system of electric train signalling as described, the means for insulating
a rail, or line of rails, which consists in the combination with a sleeper b well
coated with tar or equivalent material c, of a rail a, of any section, covered at the
fish-joints & with an insulating material e, bolts ƒ, connecting the fish plates to the
rail, passing through holes also lined with insulating material g, and a dog i also
insulated from the sleeper by a sheathing, as described with reference to Figure 4
of the Drawings.
4th In a system of automatic electric train signalling as described, and in which
a contact rail is insulated instead of the rail itself, the combination with a rail e, of
any section, of brackets g supporting the contact rail d, a contact rail d insulated
from the rail a and said brackets g by thicknesses of insulating material h, said
contact rail having inwardly bent return-ends as described, secured by clamps i
and screw-spikes, and insulated therefrom, and of sleepers insulated from the
contact rail d by the insulating material k as described with reference to Figures 8.
and 9. of the Drawings.
5th In a system of automatic train signalling as described, the employment of
resistances c placed between the battery P, and the signal post S, and equal to the
length of wire extending to said post, so as to allow of operating signals at other
posts as described with reference to Figure 10. of the drawings.