Improvements in Electrical Railways and Tramways.
Year: 1893

page_text: Date of Application, 27th Apr., 1893-Accepted, 1st July, 1893
COMI LULE
DI PUITIVATION.
Improvements in Electrical Railways and Tramways.
A communication from abroad by ALFRED DIATTO, of 12, Piazza Gran Madre
di Dio, Turin, Italy, Engineer.
I, WILLIAM LLOYD WISE of 46 Lincoln's Inn Fields in the County of
London, Consulting Engineer and Chartered Patent Agent, do hereby declare the
nature of this invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement:—
Owing to the increased use of electricity for various purposes within recent
years, attention has been drawn to the inconveniences of aerial conductors used for
conveying powerful currents, and particularly for currents of variable intensity, by
reason of their inductive action on telegraph and telephone wires.
In large towns moreover, the appearance of these conductors is objectionable,
especially where they have to be supported on posts arranged at relatively short
distances apart, or upon supports attached to houses, the general appearance and
arrangement of the conductors and supports being both unpleasant and inconvenient.
As is well known there are other disadvantages inherent to this system, especially
if the conductors are not insulated.
For the reasons above mentioned, the construction of electrical tramways with
underground conductors in preference to aerial conductors has been regarded with
favor and the great advantages likely to result therefrom have caused many
electricians to undertake this problem with the view of arriving at a satisfactory
solution. Several systems have heretofore been proposed and tried but so far as I
know they are all more or less objectionable for one at least of the following
reasons: too high cost of installation; too complicated construction; or too high
cost of maintenance.
Of the systems that have heretofore been proposed, one of the most satisfactory
is Siemen's system, as employed and at the present time still worked in the town of
Buda-Pesth. It has however the drawback of requiring a net work of under-
ground conduits that is not practicable in all towns, or which if possible, is too
expensive.
In the system forming the subject of this invention I have endeavoured to
reconcile as far as possible technical advantages with financial requirements. It
may be applied to any line of tramway or railway which is already being worked.
The negative pole of the dynamo is placed in communication with the rails, and
the underground conductor starts from the positive pole of the dynamo and is
buried at a suitable depth say of about 30 centimetres along the various branches
of the line. From this conductor, which constitutes the main conductor of the
whole system, branches are led to contact boxes located between the two rails at
distances apart that are about equal to the length of a car, as in arrangements
heretofore proposed.
My invention relates to improvements in the construction and operation of the
contact boxes; in the manner in which these are arranged; in the means employed
for supplying electric current directly from the boxes without opening them; and
in a very simple manner of solving the important question of insulation.
In the accompanying drawings,
Figs. 1 and 2 are respectively a longitudinal section, and a transverse section
showing the arrangement of a car and the adjacent part of the track according to
my invention.
Fig. 3 is a part section to a larger scale showing the arrangement of one of
the contact boxes one of the holding down bolts having been omitted, and part of
the contact piece broken away.

page_text: Fig. 4 is a diagrammatic plan of a part of the same.
Fig. 4 is a vertical cross section to a smaller scale, showing a cylindrical contact
box made of cast iron.
Figs. 5, 67 and 8 are detail views hereinafter referred to.
The
As shown in Fig. 1. the contact box A' is not in operation, so that it is not
transmitting cufrent to the car, whereas the contact box A is in operation.
boxes remain always closed, and the enclosed devices operate to place the
underground cable in communication with a metal piece b' which is suitably
insulated and fitted in the cover of the box, as shown in Figs. 3 and 6 in
longitudinal and transverse section respectively. From this piece b¹ the current
passes to the electro-motor on the car by means of the plate 62 (Figs. 1, 3 and 6) of
metal and of suitable dimensions, which connects with an arrangement of
springs c, c², and d', d² (Fig. 1) that have for object to impart to it suitable tension
and elasticity. From the motor the current passes to the rails to return to the
negative pole of the dynamo.
In order to obtain the above stated tension and elasticity in the plate 6², the
springs e¹ d' and c³ d² (Fig. 1) are mounted on slides capable of being moved by
means of a screw and hand wheel, in such a manner that they can be moved in a
longitudinal direction to produce the necessary tension which it is desired to give
to the plate, and in a vertical direction in order to establish a suitable contact of
the latter with the pieces 6' of the boxes. As the construction of these slides and
screws here referred to, is obvious, they are not shown in the drawings.
The springs d' d' are suitably insulated at their point of attachment to the slides,
and they are connected to the springs c¹ c² in such a manner that the thin part of
the former has attached to it the thick part of the latter. The bolt which holds
them together is preferably square, so as not to allow the springs c¹ c² to rotate
thereon.
The current might be taken from the boxes (A' A³) by means of a series of
brushes; it is however obvious that the means I have described are less costly, are
stronger, and require less expense of maintenance.
From
The manner in which at the desired instant, communication is established or is
interrupted between the underground cable and the contact piece 6' is shown more
clearly in Figs. 3 and 4. The insulated wire, which enters the contact box at the
point B starting from the main conductor, is attached to the safety fuse v.
the latter another wire leads to a small mercury vessel 7 being secured by means
of the screws which also serves to fix the said mercury vessel upon the insulating
piece e. Another wire attached in the same manner to a mercury vessel 72 (Fig. 4)
is connected to a stirrup 6 by means of the fastening pin f of the stirrup and a
screw (Figs. 3 and 5) so that it communicates with the contact piece b¹ by a
holding down bolt which, as stated, is not shown but which is arranged in the same
manner and serves the same purpose as the other holding down bolt 63 which is
connected to a second stirrup 65. As will be obvious the mercury cup r² might be
electrically connected with the stirrup band bolt 6 or with each of the stirrups
and bolts and thus with the contact piece b¹.
It is required when the car is to pass the contact box, that connection shall be
made between land, thus placing the underground conductor in communication
with the contact piece b, and after the car has passed that the connection shall be
broken. This is effected in the following manner :-
m² and m² are two permanent magnets connected together at their centre and
capable of rocking in the supports and P. They are arranged in such a manner
as to each have the south pole on one and the same side of a vertical plane passing
through the axes about which the magnets turn, the north pole being consequently
at the opposite side of such plane. Now assuming that the south poles of these two
magnets are on the left hand side, and that a vertical electro-magnet (M¹ or M²
Fig. 1) having its north pole pointing to the ground, passes over to the cover of the
box, the system of magnets m² m² will partly turn upon its axis in the direction
indicated by arrows in Fig. 3 and the contacts at the end of the wires o will be

page_text: raised out of the mercury in the cups 1. Thus the communication between b¹
and the underground cable previously established by the wire O, which starting
from the vessel suitably winds around the magnets m' m' (Figs. 3 and 4) and
passes into, will be broken.
By the use of the insulated wire O it is unnecessary to insulate the system of
magnets m² m², while the latter are from time to time replenished with magnetism
which without the arrangement described, they would have a tendency to lose in
the course of time.
The electro-magnets M' M² (Fig. 1) each having only a single pole directed
towards the contact box might be replaced by electro magnets of horse shoe or
U-form arranged to attract and move a piece of iron in the interior of the box
against the action of a spring or gravity, the movements of the piece of iron being
utilised in various ways to make and break the electric circuit, but this arrangement
besides necessitating a larger quantity of electro magnetic force, could scarcely
offer all the advantages of the one just referred to.
For example with my system it is not necessary that the electro magnets should
be kept in circuit during stoppages, and assuming that the current should fail from
any cause, even for an instant, the car will be able to continue its progress at once.
For this purpose it will be sufficient to push the car backwards as far as the last
contact box which will have remained included, and which will not be very far
because the driver will have taken care to stop the car immediately he perceived
that there was no longer any current. This difficulty in other known systems is
sometimes met with the aid of accumulators which are very expensive, very heavy
to draw, and very troublesome to maintain.
In other systems in which the current is taken up from insulated bars, it is also
usual to employ accumulators in order to start the car at the stopping stations,
because it is necessary to interrupt communication between the under ground cable
and the bar in order that a person crossing the rails quite close to the car shall not
be liable to receive a strong electric discharge.
It should also be noted (which is of great importance) that the cut out which I
have adopted makes and breaks communication at a time when no current is passing,
thereby obviating the possibility of producing sparks which would have amongst
other drawbacks that of consuming gradually the mercury contained in the
vessels I have not the intention of dilating here upon all the advantages of
the cut out which I have described nor upon a great number of advantages relative
to the general arrangement of my system of electric railways.
The description which follows will render more clear that which I have just set
forth.
Referring to the car shown in Fig. 1 and assuming it to be travelling in the
direction indicated by the arrow, the electro magnets M' M' are excited in series in
such a manner that if one has its south pole pointing to the ground, the other will
present its north pole to the ground, and vice versa if the current which circulates
round them be reversed. Let us now assume that the magnets m¹ m² of the contact
boxes present their south poles to the left hand of the person viewing Figure 3, then
the electro magnet M' should be so arranged as to have its south pole pointing
towards the ground, whilst M2 will have its north pole pointing to the ground, so
as in the first case to depress the contacts on the pivoted magnets, and in the second
case to raise them.
In the position in which the car is shown in Fig. 1 communication in the contact
box A', is shortly about to be established between, whilst in A' this com-
munication is about to be interrupted immediately after the car shall have passed ;
and it will be seen that for this reason the boxes will not be at all dangerous when
they are not quite underneath the car, so that traffic can take place freely around
said boxes at the stopping stations.
As long as a contact box is underneath the car it will be in circuit, which will
allow the car to resume its travel.
In order to ensure that the magnets m² m² shall positively remain in the required

page_text: position after being operated, a light spring pressure may be applied, or the said
magnets may be made hollow and be each provided internally with a round weight
such for instance as a small ball of lead which when the magnets are operated
will fall to the lower part and thus aid the magnets to remain in the desired
position.
If it be desired to cause the car to travel backwards, it will be sufficient to
reverse the current in the electro magnets M' M³ whilst operating in the usual
manner as to the rest.
In order to prolong the action of the electro-magnets M¹ M² upon the
inagnets m² m² of the contact boxes it will be necessary (especially if the carriages
are run at a high speed) to keep the said magnets M¹ M² at some distance above
the ground, and to provide their lower end, lengthwise of the carriage, with an iron
plate, as shown in Fig. 1, forming a cross section.
The sides top and bottom of the contact box which play a very important part
with respect to insulation, are of wood, but they may be formed of any other
suitable material so long as the arrangement satisfies the essential condition of
insulation.
When the four sides and the bottom of the box have been put together, they are
immersed in a bath of thin tar or of suitable varnish at a temperature sufficiently
high to allow them to become thoroughly impregnated for the purpose of protecting
them from moisture and of imparting to them a better insulating property. After
this there is applied to the bottom and to the sides, up to about the point P (Fig. 3)
a covering of suitable metal such as zinc, which should also be coated with varnish,
for better preservation.
From the point P upwards and to the cover which will have been treated in a
similar manner as just described there will be applied a plentiful coating of tar,
which should be subsequently renewed from time to time, as regards the cover
and which will constitute one of the slight expenses of maintenance that will have
to be incurred.
By the construction described leakage of current, is very effectually prevented
and the necessary insulation of the piece 6' from the ground (Figs. 3 & 6) is
ensured.
The piece is bedded upon a sheet or strip g' of suitable insulating material
such as india rubber, and the cover of the box rests on strips 92 of india rubber
placed between its edges and the sides of the box as seen in Fig. 3. These rubber
strips also serve to effect a hermetic closure of the contact box.
It will thus be seen that the current cannot leak to the rails after leaving the
contact piece b¹, save through the insulating material at 91 and 92, and also in
addition the resistance of the suitably prepared or treated wooden cover itself.
Fig. 4 represents one form of cast iron contact box.
The openings through the contact piece b¹ in the cover of each box are
hermetically closed by the holding down bolts of which only one, viz. b3 is shown,
and which have countersunk heads and are screwed at their lower ends on to the
stirrups and 6 (Fig. 3) a section of one of which is shown in Fig. 5. Either or
both of these bolts may be used to communicate the current to the contact piece
although usually, one as described is ample.
At the points where the stirrups above mentioned are connected to the cross
piece t, the latter is covered with a strip g of india rubber (Figs. 3 and 5), the mode
of attachment of the stirrups being clearly shown in the drawings.
When the contact box is once closed, arrangements may be made to prevent the
bolts of the stirrups being improperly removed as it is only for repairs that removal
is required.
The contact box may rest on a foundation of concrete and should be so strong
that heavy loads which may pass over it will not damage it. The cover as shown
in Fig. 3, forms with the cross piece t by means of the bolts and the stirrups of
attachment, a compound beam. Moreover it can easily be arranged by notices or
otherwise that heavy carts are not to pass over the boxes and this can be more

page_text: easily avoided as the boxes are located about 6 metres distant from one another.
However the said boxes are made sufficiently strong to prevent injury in case of a
heavy waggon going over them.
The contact boxes have a height of about 25 centimetres so that the soil need be
excavated only to a very small depth in order to lay the contact boxes and the
insulated main conductor and thus avoiding the drawback of meeting with gas,
water or sewer pipes. The said boxes will not cause inconvenience to foot
passengers, or to vehicular traffic, because the centre of the cover will be only
about 4 cm. at the highest point, above the ground the said 4 cm. forming the rise
of an arc of a circle having a chord of about 40 cm. that is to say the curve of the
cover will be scarcely felt.
For tramways or railways where the roadway is private or where the rails
project above the surface of the track, the boxes may also project from the ground
to a height of several centimetres which projecting portion is suitably coated with
tar, and then the track between the two rails has no longer need of any special
treatment.
It will in all cases where the contact boxes are almost flush with the roadway,
be well to make use of a special stone clearer to protect the current collecting
plate b² from pebbles or other obstructions which might be in line therewith and
apt to come in contact with it. This stone-clearer may be of very simple
construction.
One form is shown in Figs. 7 and 8 which are views at right angles to one
another. It comprises a wheel of a width slightly greater than the plate journalled
in a fork F of a steel spring arm L secured to the underframe of the car by a
flexible joint I. This wheel is normally situated slightly above the ground (at a
height of about 2 cm.) and is capable of rotating in F on the axle D. In order to
enable it to pass over the contact boxes, the aforesaid stirrup is made capable of
yielding below the point of attachment I. The wheel R has at its periphery a
rubber tyre.
In winter, if necessary, there may be employed a snow clearer N (Fig. 1) and a
suitable brush which will precede the electro-magnets and will clean the contact
pieces.
By employing two plates 62 on the cars and two contact pieces on the contact
boxes, a return cable for the electric current may be used instead of utilizing
rails and the earth for this purpose although this would detract from the simplicity
of the various apparatus and the working, besides increasing the cost of installation
of the apparatus.
It is obvious that in adopting the system forming the subject of the present
application, the details of construction may be modified without departing from
the nature of the invention, and I therefore do not intend to restrict my invention
to the constructional details described and illustrated in the accompanying
drawings.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In the underground distribution of an electric current for electrical railways
and tramways by means of contact pieces arranged along the track and of a
collecting plate secured to the vehicle to be propelled, and sliding upon the said
contact pieces, the arrangement by means of which the contact pieces b' are
connected to the underground conductor comprising mercury vessels 1, 2, and a
conductor o surrounding a permanent magnet m¹ m² operated by the vehicle itself
through the electro-magnets M¹ M³, which cause the said permanent magnet to
assume a position for making or breaking the electric connection between the main
conductor and the motor on the vehicle substantially as described and shown for
the purpose specified.
2. In the arrangement referred to in the [preceding claim, for the purpose of

page_text: avoiding sparkling in the mercury vessels 71, 72, the arrangement of the electro-
magnets M, M2, at a suitable distance from the collecting plate 6, so as to
complete the electric connection when the said plate comes into sliding contact
with the contact piece 6' and not to interrupt such connection until the plate has
left the said contact piece, substantially as described and shown for the purpose
specified.
3. In the arrangement described in Claim 1, a device for collecting the current,
consisting of a plate 62 secured to two sets of springs c, d, c, d, capable of a
longitudinal and transverse movement, substantially as described and shown for
the purpose specified.
4. In electrical railways and tramways, the arrangement of the device for
making and breaking the connection between the underground cable and the
contact pieces in permanently closed boxes A' A2, in the covers of which and
projecting more or less from the ground, are arranged the insulated contact
pieces b¹ for the purpose of effecting a direct distribution of the current,
without opening the boxes, substantially as described and shown for the purpose
specified.
Dated this 7th of A 1 1000
W. LLOYD WISE,
Per F. J. Brougham,
46, Lincoln's Inn Fields, London, W.C.