Improvements in and relating to Electric Railways.
Year: 1897

page_text: Date of Application, 28th Dec, 1897-Accepted, 12th Feb., 1898
COMPLETE SPECIFICATION.
Improvements in and relating to Electric Railways.
We, THE BRITISH THOMSON-HOUSTON COMPANY, LIMITED, of 83, Cannon Street,
in the City of London, Electrical Engineers, do hereby declare the nature of this
invention (which has been communicated to us from abroad by William B. Potter,
of Schenectady, in the County of Schenectady, State of New York, United States
of America) and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
The present invention relates to electric railways in which the energy is obtained
from a third rail or conductor situated between or just outside of the tracks and
suitably insulated therefrom. The invention has for one of its objects to provide
a system in which the continuity of the conductor rail is interrupted at the
various stations, crossings or other predetermined points along the line of travel,
and sectional conductors substituted therefor. These sections are normally discon-
nected from the source of supply, but are rendered active by the approaching
train. The relation of the sectional conductors and the contacts carried by the
vehicle is such that only the conductor directly under the vehicle is active; this
eliminates all danger from shocks to persons crossing the tracks at a point near
the train. It sometimes happens that it is desirable to leave a train standing at
a station or siding and to interrupt the circuit between the sectional working con-
ductors and the source of supply; this invention has for one of its objects to provide
means for interrupting the circuit in such a manner that all of the sectional
working conductors are dead and no act of a person on the train can cause them to
be included in circuit again.
A further object of the invention is to arrange the circuit closing switches so
that the station agent has control over them; when a train is ready to proceed, he
can close the proper switch to supply current to the section upon which the train is
located.
A further object of the invention is to arrange the contact devices carried by
the train, and the sectional conductors and switches, in such relation that a train
may pass through the station and receive current from each section; yet
after the train stops at a station and the sections are "killed" it cannot be started
until the station agent closes the proper switch or switches.
The invention also has for its object to provide sectional conductors, normally
disconnected from the source of supply, at points where the railroad intersects
the public highway, or at other points wherein it may be deemed best for the
public safety. The switches at these points may be so arranged that they are under
the control of a gateman or signal-tower operator, as well as the engineer of the
train,
A further object of the invention is to provide means whereby the switches
between the supply conductor and the sectional conductors may be locked in their
open position to form a block system for the train by cutting off the source of
supply, or locked in their closed position to establish the continuity of the third-
rail system.
In the accompanying drawings, Fig. 1 is a diagrammatic view of a third-rail

page_text: system with normally disconnected contact sections at a station; Figs. 2 and 3
are detail views of suitable switch mechanisms.
C is
A indicates the rails or negative conductors, connected to the generator B;
the third-rail conductor, and is connected to the positive side of the generator B;
D is the feeder main extending along the line of travel, to which the third-rail C
is connected at suitable intervals. EE and E are switches adapted to connect
G G¹ are
the feeder main D with the high-potential sectional conductors FFF;
secondary sectional conductors employed in closing the switches E E¹.
I is the moving vehicle, provided in the present instance with a single motor J,
but in practice any number may be employed. KK are respectively high-
potential and secondary contact shoes carried by the vehicle, and are so arranged
that they will span the distance between the sectional conductors and also that
between the sectional conductors and the third-rail C.
L is a signal tower or other suitable building, and the structure M shown in
A connection a extends
dotted lines represents a station extending over the track.
from the conductor C to one terminal of the switch N located in the depot or
signal tower, as the case may be, and connected with three separate terminals
adapted to be engaged by the switch blade are the leads 6 6¹ bª connected respectively
to the energizing coils of the switches E E E².
The switches E E E in practice are mounted on a switch board in the station,
and within easy reach of the operator, but in the event of their being located at
some distance therefrom, beside the track for example, the switch N may be used.
The contact shoes K and K¹ are connected together by means of a switch O,
which may be either a separate switch or form a step in the motor controller. As
the vehicle I progresses from right to left a circuit is established from the shoe K,
switch O, secondary contact G¹, energizing coil of switch E¹ to negative rail A;
this causes the switch E¹ to close, and current to the motor is supplied therefrom.
As the vehicle progresses, this action is repeated, and when the vehicle stops, the
switch which energizes the particular section on which the vehicle stands will
maintain the closed relation due to the shunt energizing coil.
If it is desired to leave a train standing at a station or siding and to prevent it
from being started without the knowledge of the station agent, the switch O is
opened, which will permit the switch or switches energizing the sections to open,
and by no act of a person on the train can they be closed again. It is necessary
for the station agent or operator to either close the switch to a particular section by
hand or by means of the switch N.
If the switch O forms a step in the controller when the power is shut off and the
train has been receiving current from the sectional conductors, the switches E E E²
will open and the train cannot start until the operator again closes the switches,
either by hand or by means of the switch N. When the switch N is employed, the
current enters from the conductor C, wire a, switch N, wire b, energizing coil of
switch E to ground; this will cause the switch E to close and the conductor F
will receive current from the supply main D, which will be transmitted to the
motor J through the shoe K. As soon as the vehicle I has travelled to a point
where the forward portion of the shoe K touches the conductor C, the motor will
receive current therefrom and proceed as in any third-rail system. If it so happens
that the train comes to a standstill over the sectional conductor F1 or F2, the
switch N is actuated so as to close the circuit through wire b¹ or as the case
may be.
Assuming that the train did not stop at this particular station, and it was
desirable to receive current from each of the conductor sections, the switch (
between the shoes K and K¹ would be closed and the operation would be as
follows: A train approaching from the right would receive current from the
conductor C and as soon as the forward end of the shoes K and K engaged with
the sectional conductors F1 G¹ a shunt circuit would be formed through the
switch O, energizing coil of the switch E, to the negative rail A; this would close
the switch E', and current to the motor would be received from the conductor ".

page_text: The same action is repeated as the vehicle progresses, the relation of the shoes
and contacts being such that the circuit of the advance section is complete before
leaving the rear section.
Fig. 2 shows an enlarged detail view of the switch E, in which a blow-out
magnet P is included in the circuit from the source of supply D to extinguish the
are formed when the circuit is interrupted. On the right-hand end of the arma-
ture lever is a handle h provided with a bolt h¹ adapted to engage with holes in
the stationary piece h2 when it is desired to lock the switch in either its open or
closed position.
Fig. 3 shows a further modification in which a few turns of series coil are
employed in conjunction with the shunt for holding the switch in its closed position.
In the event of its being desirable to establish the continuity of the third-rail
system and dispense with the use of the shoe K¹ and the automatic operation of
the switches E E E², the latter are closed by hand and the bolts h¹ shot into a
hole in the piece 2, holding them in their closed position.
If it is desirable to block an approaching train, the switches closing the several
sections are locked in their open position by means of the bolt h¹ engaging with a
hole in the stationary piece h²; this prevents the automatic operation of the switches,
and the supply of current failing, the engineer is at once informed, even though he
has run by his signals.
By making the space between the parts of the conductor C of considerable length,
the train may be made to stop of its own accord, but ordinarily the brakes are
applied by the engineer.
Having now particularly described and ascertained the nature of the said inven-
tion (as communicated to us from abroad) and in what manner the same is to be
performed, we declare that what we claim is:-
-
1. In an electric railway, the combination of a third or main working conductor
connected with a source of supply, the continuity of which is interrupted at pre-
determined points, a conductor section located between adjacent ends of the main
working conductor and insulated therefrom, a moving vehicle, a contact shoe
carried by the vehicle arranged to complete the circuit between the conductor
section and the source of supply, and means located in any convenient place, for
controlling the current supplied to the conductor section irrespective of the opera-
tion of the vehicle.
2. In an electric railway, the combination of a third or main working conductor
connected with the source of supply, the continuity of which is interrupted at pre-
determined points, a set of sectional conductors located between the ends of the
main working conductor, switch magnet coils connected between the secondary
sectional conductors and the return circuit, and a connection extending from each
switch, so arranged that the circuit between the source of supply and a sectional
conductor can be controlled.
3. In an electric railway, the combination of sectional conductors, switches for
closing the circuit between the conductors and a source of supply, means carried
by the moving train or vehicle for closing the sections in advance of the train, and
additional means independent of the vehicle for closing the circuit between the
sectional conductors and the source of supply.
4. In an electric railway, the combination of a sectional working conductor,
means carried by the moving vehicle for establishing connection with the working
conductor, means for rendering the sections of working conductor inactive
after the power has been shut off from the motor, and means inde-
pendent of the train or vehicle for closing the circuit between the source of
supply and the sectional working conductors.
5. In an electric railway, the combination of a main working conductor or con-
nected to a source of supply the continuity of which is interrupted at certain
points, sectional conductors substituted at the point of interruption, a main
contact shoe carried by the vehicle making contact with the working and sectional

page_text: conductors, a secondary sectional conductor also located at the point of interruption
of the main working conductor, and a shoe normally idle, but arranged to make
contact with the secondary conductor, and acting in conjunction with the main
contact shoe to close the circuit between the source of supply and the secondary
conductors.
6. In an electric railway, the combination with a source of supply, sectional
working conductors normally disconnected therefrom, switches for connecting the
conductors with the source of supply, and locking devices for maintaining the
switches in their open and closed position irrespective of the operation of
the train.
7. In an electric railway, the combination of a main working conductor con-
nected with the source of supply, the continuity of which is interrupted at certain
points, sectional working conductors located between the ends of the main conductor,
contact devices carried by the vehicle, switches for closing the circuit beween the
source of supply and the sectional working conductors, and a lock for each switch
to maintain it in its open or closed position irrespective of the operation of the
train.
Deted the 28th day of December 1897