Improvements in Electric Railways.
Year: 1892

page_text: Date of Application, 30th June, 1892-Accepted, 30th July, 1892
COMPLETE SPECIFICATION.
Improvements in Electric Railways.
I, BENJAMIN JOSEPH BARNARD MILLS of 23 Southampton Buildings in the
County of Middlesex, Patent Agent, do hereby declare the nature of this invention,
a communication to me from Edward Hibberd Johnson, of No. 44 Broad Street,
New York City, in the County and State of New York, United States of America,
Electrician, and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement :—
The invention relates to that class of electric railways in which one or more
of the supplying conductors are placed in a conduit beneath the surface of the
ground, contact being obtained by means of suitable current collectors carried
by the moving cars and entering said conduit through an opening at the surface of
the ground.
The object of the present invention is to provide a construction for the conduit,
the current collector and the devices for keeping the conduit clean, whereby, the
loss by breakage from one side of the circuit to the other, due to the presence of
moisture or foreign bodies, is reduced to a minimum, and whereby, the conductor
and the conduit itself may be kept clean and continuously freed from moisture and
from dust, snow and other foreign materials, liable to impair the efficiency of the
travelling contact and obstruct its passage.
The invention is illustrated in the accompanying drawing, in which:
Figure 1. is a perspective view of a portion of an electric railway conduit
embodying the present invention.
Figure 2. a longitudinal section of the same, showing the cleaning scoop and the
current collecting device:
Figure 3, a front view of the cleaning scoop; and
Figure 4, a section illustrating another form and arrangement for the conductor.
A is a continuous body of insulating material placed underground between the
rails B, B, and held and supported in any suitable manner. As shown, this body,
which constitutes the conduit, is held in a suitable iron frame-work C, provided at
the surface of the ground with the slot-irons a. a.
The insulating body A may be made of any suitable, durable, moisture-proof,
insulating material, such as a vitreous material, stone, slate or cement, or it may be
of wood or other fibrous material impregnated or treated in any of the well-known
ways with any substance which renders it moisture proof and increases its insulating
properties. The said insulating body A is provided with a groove D, extending
longitudinally, throughout its length, said groove being open at the top of
the conduit, and preferably, closed at the bottom. This is a narrow, open,
unobstructed groove, having at no point in its depth a width greater than its width
at the top or surface.
Preferably, it is made widest at the top and narrows gradually towards the
bottom, as shown. Such groove may have at the top a width of, say, three-
quarters of an inch, and at the bottom, say, one-half of an inch.
Preferably laid in the bottom of this groove is the conductor E, which, preferably,
has a grooved upper surface, as shown. It is preferred to make this conductor of
iron, and to use therewith a magnetic contact device to be presently described, but
if such a magnetic contact device is not employed, the conductor may be made of
copper or other suitable metal. Any suitable means may be employed, if desired,
to hold the conductor in place, such means being such as will not interfere with the
passage of the current collector along its upper side.
The groove D constitutes the conduit chamber for holding and protecting the
conductor. The opposite side of the circuit is preferably formed by the rails and

page_text: the earth, in the ordinary way. It will be seen that by using as the conduit
chamber the single narrow slot or groove, the loss by leakage through moisture is
practically done away with, since by making the slot of sufficient depth it is
evident that, even if the slot were entirely filled with water, the body of water
would be so small as not to furnish sufficient conductivity to allow the passage of
sufficient current to seriously affect the operation of the railway and this result may be
obtained with certainty by estimating the resistance of a body of water and of the
ordinary refuse of the street, the size of the conduit chamber and making the slot
of such depth as to raise this resistance to a point sufficient to accomplish the
desired result.
Since, in practice, it is extremely improbable that the chamber will ever be con-
pletely filled with water, it will be seen that by this expedient, leakago from the
conductor E to the surface is practically done away with.
In Figure 2, F indicates a portion of a street car.
Attached in any suitable
manner to this car is the cleaning scoop G, which is a plough having a width and
shape in cross section such that it substantially fills the conduit chamber D,
but, preferably, so as to not touch the sides of the chamber when placed
centrally therein. It is formed with a sloping front edge, as shown, and when
passing through the conduit it takes up all dust and other materials which may
accumulate therein, carries them to the surface and throws them out of the slot
opening. By this means, the conduit may be kept entirely clean.
Preferably the plough G has attached to it a brush H, which bears on the
conductor E, for the purpose of cleaning the surface thereof. It is preferred to
make the body b of the plough or scoop G of insulating material, such as hard
wood. There being no great wear upon it, such material will readily answer the
purpose, and the plough may be readily changed if it wears out.
By making this portion of insulating material, any danger of a short circuit
through the plough between the conductor E and the slot-irons a is avoided.
The upper portion c is preferably made of iron since it may wear against the slot
irons, and the toe d of the plough or scoop is also shod with iron. The scoop may
be connected with the car in any suitable or well-known way which will enable it
to maintain the same position with reference to the conduit and to follow the car as
it passes around curves; and in the case of a car which does not travel always in
the same direction, it may be removably attached to the car, so as to be taken out
and placed at the other end of the car when necessary, both ends of the car being
provided with suitable attaching devices for holding it.
The plough G may itself have an attachment for collecting the current from the
conductor B. It is preferred, however, to employ a separate current collector, and
preferably, one which is maintained in contact with the conductor by electro-
magnetic attraction. Such current collector consists of two brushes I. I. of iron
wire, each held in a suitable back K, and such backs being united by an iron core,
around which the wire which conveys current to the motor is given a sufficient
number of turns, one end of such wire being soldered or otherwise connected to the
magnet and the motor wire then being carried to the car, as shown at L.
The current collector, like the cleaning scoop, is connected with the car in any
suitable manner, and preferably so as to have its inclination reversible, so that
it will trail behind the centre of the car no matter in which direction the car is
moving.
This electro-magnetic current collector will adhere to the conductor with great
force, although it may readily be drawn along it, and its use insures an effective
electrical contact with the conductor at all times.
In the form shown in Figure 4. the conductor chamber is formed with offsets or
shoulders near its bottom, and the conductor consists of a V shaped spring sprung
into place beneath said shoulders and held thereby.
The conductor in the conduit may in some cases, and especially when the road
passes through low lands where the conduit is particularly liable to become filled
with water, be made in detached sections, each of which is separately connected

page_text: with a main conductor placed underground, the connection being made through
electro-magnetic or other devices, so that the circuit to a section is completed
only when a car is upon it, whereby leakage between the conductors is still further
avoided.
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. The electric railway conduit containing a conductor, and consisting of a body
of material having a chamber for the conductor the diameter of which chamber
decreases continuously from its surface opening to its bottom, substantially as
hereinbefore described.
2. The cleaning device carried by the car, the same being of about the same cross-
section as the conduit chamber and formed so as to throw material from the conduit
to the street surface, substantially as hereinbefore described.
3. The current collecting device consisting of brushes forming poles of an
electro-magnet and arranged to travel on an iron conductor, substantially as herein-
before described.
Dated this 30th day of June 1892.
Dated this 30th day of June 1892.
B. J. B. MILLS,
By Harris & Mills,
23, Southampton Buildings, London, W.C., Agents.