Improvements relating to Electric Railways.
Year: 1895

page_text: Date of Application, 7th Dec., 1895
Complete Specification Left, 7th Oct., 1896-Accepted, 7th Nov., 1896
PROVISIONAL SPECIFICATION.
Improvements relating to Electric Railways.
I, REGINALD BELFIELD, of 32, Victoria Street, in the City of Westminster,
Electrician, do hereby declare the nature of this invention to be as follows:-
My invention relates to electric railways of the kind or class in which a series
of exposed terminals or segments of a conductor are provided along the track
these terminals or conductor segments being arranged in connection with switching
devices so that said terminals or segments are energized only when a car is over
the same or in a position to take current therefrom.
According to one method heretofore employed these switching devices are
operated by means of a current sent through them from the car, from a battery
carried on such car for example, which current actuates an electromagnetic switch
for making and breaking the connection between the mains and the exposed track
terminals or conductor segments aforementioned.
In the present invention I improve the switching apparatus aforementioned and
I also provide for actuating the switches by independent devices said independent
devices being themselves controlled by an electric current from a battery or its
equivalent carried on the car or by devices mechanical or otherwise operated on or
from the car.
In carrying my invention into effect I may so arrange the switching apparatus that
a series of single exposed terminals is utilised for conducting the current from the car
to actuate the switch and also to conduct the current from the main to the car motor
after the switch has been operated. In this arrangement the contact shoe carried
by the car is made in two parts electrically insulated from each other. One of the
portions of the shoe is connected to the battery or equivalent carried by the car so
that when it touches an exposed terminal the switch is operated to put the terminal
in connection with the main. In some forms of this apparatus I find it convenient
to use polarized armatures or magnet cores for or in the switch magnets. I also
arrange that when the armature is not attracted a second pair of contacts are
connected together whereby the current from the battery or its equivalent carried
by the car is afforded a path round the electro-magnet of the switch.
Instead of causing the current delivered to an exposed terminal to operate the
switch to connect the said terminal to the main it may be arranged to cause the
terminal in front or behind the first mentioned terminal to be so connected. In
some cases it may be desirable to make the contact shoe in three parts placed end
to end the middle part being connected to the car-motor.
When it is desired to actuate the switches by means which are controlled by the
car and not energized therefrom I so arrange that when the car arrives at a place
on the track where another terminal or set of terminals is required to be connected
with the main leads so as to become energized, a current is caused to flow through
an electromagnet located in a suitable box adjacent to the track. The electro-
magnet acts like a kind of relay and permits the main switch to be actuated by
other means such as compressed air or by an auxiliary current to connect the
main to the terminal or terminals. At the same time the electromagnet appro-
priated to the terminal which the car is leaving being no longer energized the
switch mechanism operates to break the connection between the main and the said
terminal or terminals.

page_text: When I use compressed air or other fluid to actuate the switches I preferably
provide a reservoir for each switch such reservoir being connected with the main
supply pipe through a non-return valve. By doing this I am enabled to use a
small supply pipe and risk of accident is diminished.
Instead of arranging that the electromagnet which controls the switch
mechanism shall be energized during the whole time the contact shoe on the
car is engaged with one terminal I may provide for sending a current round
the said magnet as soon as the shoe touches the terminal and thereby close the
connection between the terminal or terminals and the main, the connection being
broken when the car leaves the terminals.
By my improved method of operating, the power which actuates the main
switch is only controlled by and not furnished from the car and a very positive
and assured action of the main switch is thereby secured.
Furthermore I provide means whereby if an accident occur so that the switch
or the electromagnet fails to work or the armature or armatures stick the con-
nection to the main shall be broken, or a signal visual or audible shall be given
and attention thereby directed to the faulty mechanism. I sometimes arrange
that both the connection shall be broken and a signal given. Or I may provide
that a short circuit shall occur under these circumstances whereby the fuse on the
main lead supplying a series of terminals forming a section of the line shall be
broken.
The above described methods of operating are very suitable in cases where
it is desired to supply the cars with power from an alternating current system
the operation of the switches being altogether independent of the current in the
mains.
In electric traction systems operated by alternating currents with transformers I
sometimes divide the track into sections of suitable length each section having a
series of terminals or groups of terminals to supply current to a car as it travels on
the section. The terminals or sets of terininals in one section are adapted to be
joined in succession to the secondary coil of a transformer the primary coil of
which is connected to the main only as long as the car is in the section. Hence
if a section of the line be empty of cars not only are all the track terminals or
exposed conductor sections disconnected from the secondary of the transformer but
the primary circuit of said transformer is also broken. A double element of
safety is therefore obtained.
This principle may also be applied where the line is operated with direct
currents the feeder to the lead supplying a series of terminals forming a section
of the line being adapted to be made and broken when a car enters or leaves the
section.
I may further arrange that the supply of current to a section of the line shall
be controlled by devices independent of the cars on the said section but
depending on the state of the section in advance. By this means a positive block
system may be constituted in which under normal conditions of working there is
always maintained a section clear of cars behind and in front of every car.
Another method of operating where alternate currents are used for supplying
power to the car is as follows:-A battery or its equivalent is joined in series
with an inductive resistance and across the car motor terminals, the electromagnet
operating the switch has also an inductive resistance in series with it and is joined
across the exposed terminals in the track. When the car arrives at a terminal or
group of terminals the battery on the car energizes the switch magnet, which was
not done by the alternating current, and thereby connects the mains to the track
terminals. The alternating current is therefore supplied to the car motor but
does not flow through the battery because of the inductive resistance in series
therewith. When alternating currents are used for operating the line, I sometimes
employ in place of a battery carried by the car a transformer supplied from the
main current for actuating the switches.
I find it very convenient for various reasons to locate the boxes containing the

page_text: switching devices between the track rails and I then utilise the exposed terminals
and their insulating blocks as covers for the said boxes. This arrangement is
more especially applicable to the system of electric traction described in the
Specification of British Letters Patent No. 14445 of 1894 and 3358 of 1895.
Dated this 7th day of December 1895.
W. P. THOMPSON & Co.,
31, High Holborn, London, W.C., Patent Agents for the Applicant.
I, REGINALD BELFIELD, of 32, Victoria Street, in the City of Westminster,
Electrician, 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:-
My invention relates to electric railways of the kind or class in which a series
of exposed terminals or segments of a conductor are provided along the track
these terminals or conductor segments being arranged in connection with switching
devices so that said terminals or segments are energized only when a car is over
the same or in a position to take current therefrom.
According to one method heretofore employed these switching devices are
operated by means of a current sent through them from the car, from a battery
carried on such car for example, which current actuates an electromagnetic switch
for making and breaking the connection between the mains and the exposed track
terminals or conductor segments aforementioned.
In the present invention improve the switching apparatus aforementioned and
I also provide for actuating the switches by independent devices said independent
devices being themselves controlled by an electric current from a battery or its
equivalent carried on the car or by devices mechanical or otherwise operated on
or from the car.
In order that my invention may be clearly understood I will proceed to describe
the accompanying drawings which illustrate by way of example various methods
of carrying the same into effect.
Figures 1 to 4 are diagrams of electrical connections.
Figure 5 is a diagrammatical representation of an improved switch apparatus.
Figure 6 shows the same apparatus with the valve in another position.
Figures 7 and 8 are similar views illustrating a modified form.
Figures 9 to 12 are views similar to Figures 5 to 6 illustrating a further
modification of the apparatus shewn in said figures.
Figure 13 is a diagram of the electrical connections in another system of switch
apparatus.
Figure 14 is an elevation shewing another form of switch hereinafter explained.
Figures 15 and 16 are diagrains of electrical connections hereinafter explained.
Figure 17 is a vertical section shewing an improved combined insulated terminal
and switch box.
.
Throughout the drawings A, A', A2
indicate exposed terminals
located in the track which I shall hereinafter refer to as "track terminals." B is
the connecting bar carried by the car adapted to make contact with the track
terininals, C is one of the mains through which current is supplied from the power
station to the track terminals, D is a battery carried by the car the function of
which is to cause the track terminals to become connected to the main when
necessary, E is a third rail or its equivalent connected by a wire to one side of
the switch-electromagnet to be energized by the battery D, one pole of said
battery being connected to the rail E by a brush or the like carried by the car.

page_text: The coil on the electromagnet which is in the battery circuit is generally referred
to by the letter F.
The general principle of the railway systems to which my invention relates is
that by some means the battery D is enabled to send a current through the coil F,
and the coil F either directly or indirectly causes a connection to be made from
the track terminals to the main thereby permitting energy to be supplied to the
car motor.
In Figure the contact bar B is made in two parts B, B' placed end to end
electrically insulated from each other, the part B' being connected to the battery D
and the part B to the car motor. A single series of track terminals A, A¹ is
provided and it will be readily understood from inspection of the diagram that as
soon as the part B1 of the contact bar touches an exposed terminal the coil F is
energised and the switch magnet G attracts its armature G¹ which causes the
circuit to be made through the supply wire c thereby connecting the main C to
the terminal A. When the part B₁ leaves terminal A the part B of the bar
comes into contact therewith and takes current through the wire c the coil G³
taking the place of coil F which is no longer energised by the car battery.
In some forms of this apparatus I find it convenient to use polarised armatures
or magnet cores for or in the switch magnets.
I may arrange that when the armature G₁ is not attracted a second pair of
contacts are connected together as shewn in Figure 2 whereby the coil F is
disconnected from the rail E as long as the terminal A is connected to the main.
Instead of causing the current delivered to a track terminal to operate the
switch to connect the said terminal to the main it may be arranged to cause the
track terminal in front or behind the first mentioned terminal to be so connected.
Figure 3 shews the connections in the latter case and when the part B' of the
bar makes contact with the track terminal A, a current flows through the coil F
on the magnet appropriated to terminal Á¹ causing the contacts g¹, g to be
connected so that said terminal A¹ is connected to the main through the wire c¹.
The current from the battery D through coil G2 on the electromagnet of
terminal is not sufficient to operate the switch, this switch will however be
operated as soon as the part B₁ reaches the track terminal in front of track
terminai A.
I sometimes make the contact bar in three insulated parts as shewn in Figure 4
the two end portions being connected to the battery D and the middle portion to
the car motor. The electromagnet of each terminal A for example is wound with
two coils F, F one of which is energized when the battery D is connected to the
terminal on one side of the terminal A under consideration and the other of which
is energised when the battery D is connected to the terminal on the other side of
the terminal A, this will be readily understood by inspection of the diagram.
When it is desired to actuate the switches by means which are controlled by
the car and not energized therefrom I so arrange that when the car arrives at a
place on the track where another terminal or set of terminals is required to be
connected with the main leads so as to become energized, a current is caused to
flow through an electromagnet located in a suitable box adjacent to the track.
The electromagnet acts like a kind of relay and permits the main switch to be
actuated by other means such as compressed air or by an auxiliary current to
connect the main to the terminal or terminals. At the same time the electro-
magnet appropriated to the terminal which the car is leaving being no longer
energized the switch mechanism operates to break the connection between the
main and the said terminal or terminals.
When compressed air or other fluid is used to operate the switches 1 preferably
provide a reservoir for each switch such reservoir being connected with the main
supply pipe through a non-return valve. By doing this I am enabled to use a
small supply pipe and risk of accident is diminished. In Figure 5 I shew a
diagrammatic sectional view illustrating this arrangement. Fis the coil ou the
electromagnet, G' the armature thereof, g, g' are the contacts of the switch and

page_text: g2 is the bridge piece, H is a valve casing within which a valve H' is adapted to
move back and forth, said valve is connected by a stalk H' to the armature G¹ of
the electromagnet. J is a casing having two diameters at different parts of its
length a piston J' being provided of a shape corresponding to that of the casing
and adapted to move backward and forward therein. The bridge piece g² of the
switch is, attached to a rod g³ having a head g. The piston J has a sliding
connection with the rod 3 as shewn, the relative movement of the two being
limited by the length of the cavity J2 within which the head 9 of the rod g³ is
received. is a spring provided to assist in opening the switch, and K is the
reservoir for compressed air. The air pipe from the main which supplies
compressed air to the system enters casing J at port 1. The valve H¹ is provided
with the cavities h, and the casing H provided with ports 2 to 8 as shewn.
The piston J has cross channels and as shewn and the casing J is provided
with the ports at the positions indicated. The ports are connected by pipes as
follows Port 2 to port 4, port 12 and port 16, port 3 to port 5, and port 9,
port 6 to port 13, port 8 to port 10 and to the reservoir.
The operation of the apparatus is as follows:-The diagram Figure 5 shews
the apparatus in the position when the armature G¹ is not attracted and Figure 6
shews the position when the armature is attracted.
Referring to Figure 5 it will be seen that in this position of the valve H' the
rear end of the piston J¹ is not under air pressure since ports 3 and 5 are closed,
also the channel j connects ports 1 and 10 hence the reservoir K is open to the air
supply. If now a current be sent through coil F and the armature G₁is attracted
the valve H¹ takes up the position shewn in Figure 6. In this position the
reservoir K will be connected through port 8, channel and port 3, to port 9.
The rear end of the piston J' will therefore be subjected to air pressure which
will overcome the pressure of the spring and cause the piston to move out
closing the switch contacts g, g¹ through the medium of the bridge piece 92. The
air in front of the piston is swept out through ports 13, 6, channel and port 7
as the piston J¹ advances until the piston has nearly reached the end of its stroke
at which time port 13 will be closed and channel connects port 10 to port 14
whereupon air from the reservoir passing through said ports aud channel anl
through port 12 presses upon the front end of the piston. Since the area of said
front end is considerably larger than that of the rear end and the pressure of air
per square inch is the same the piston moves back, the bridge piece of the switch
does not, however, partake of this rearward movement in consequence of the end
play provided by the channel J2 between the head of the piston rod and the
piston. As soon as the piston J' moves back in the manner described port 10 is
closed and the piston again moves forward. This backward and forward motion
of the piston will continue until the total pressure including that of the spring g
on the front end of the piston J¹ is equal to the total pressure on the rear end
thereof. When this is the case the piston will be in equilibrium and it will be
clear also that the pressure in the front portion of the cylinder J will be less
than that in the rear portion of said cylinder. When the current is cut off from
coil F the armature G¹ being no longer attracted moves away from the electro-
magnet and the valve H' assumes the position shewn in Figure 5 aud port 8 is
closed. Port 9 will be then connected to port 12 through port 2 channel h and
port 3, and also through port, channel and port 5, the air pressure of each
end of the piston J₁ will therefore be equal and since the area of the front end is
larger than that of the rear end the piston J¹ will move backwards and open the
switch. During the backward movement of the piston the air escapes from the
cylinder through the port 11. It will be observed that in this device air from
the reservoir is used to close the switch when the armature G' is attracted, but
that when armature G¹ is released no air will be required from the reservoir in
order to effect the opening of the switch this being caused by the_spring g
assisted by the difference in the areas of the two ends of the piston J¹ each of
which areas is pressed upon by the same pressure per square inch. Hence there

page_text: results considerable economy in the use of the compressed air.
Moreover if any
accident occurs to the main air supply the reservoirs will hold sufficient compressed
air to continue working the switches for some time thereby obviating risk of delay
throughout the entire system, while a main supply is being put right.
F
Figures 7 and 8 shew a modification of the valve and devices connected there-
with in which provision is made for breaking the connection of the track terminal
to the main if the switch or electromagnet fails to work or if the armature of said
magnet sticks. The electromagnet G having the coil F thereon is provided with
two armatures G3, G4 each of which is connected to an independent valve controlled
by a spring as shewn. The valves, marked L, M, are located in a casing H and
are provided with the various cavities 12, mm² m² as shewr, in each valve there
is also a cross channel 13, m³ not in connection with the other cavities in the valves.
Jis the piston which is connected to the bridge piece g2 of the switch and is
adapted to move in a cylinder J in the usual manner being controlled by the
spring 9. The casing H is provided with the ports 18 to 26 as shewn and the
cylinder J with the ports 27 and 28. Ports 18 and 21 are connected to the air
supply pipe and port 25 is connected to port 27, and port 23 to port 28. In
Figure 7 the apparatus is shewu in the state when no current is passing round the
magnet coil F and the armatures G³ and G are not attracted. The air supply
is cut off at port 18 and is connected through port 21, channel 13 port 23 and
port 28 to the cylinder J and assists the spring to move the piston J' in the
direction of the arrow and so break the circuit in the supply wire thereby
disconnecting the track terminal from the main. If a current flows through the
coil F the armatures G³, G' are both attracted and the valves M, L, move to the
position shewn in Figure 8, port 21 is closed and the air supply connected through
port 18, channel m³, port 25, and port 27 to the other end of the cylinder J thereby
forcing the piston J' to move in the opposite direction to the arrow and close the
switch compressing the spring 9. Port 23 will be connected to port 24 so that
the air in the cylinder J can escape through ports 28, 23, and 24. If the circuit
through coil F be broken the arinatures G³ G move away from each other and
restore the apparatus to the position shewn in Figure 7. Compressed air flows
into cylinder J through port 28 as above mentioned and port 27 is connected to
the atmosphere through port 25 channel m² and port 26. If, however, one of said
armatures sticks, say armature G³, and does not move away from the magnet the
circuit through the supply wire will still be broken since the valve M will move to
such a position that port 25 is connected to port 26 and since port 23 is still
connected to port 24 the pressure of both sides of the piston J' will be equal to
the atmospheric pressure and said piston will therefore move in the direction of
the arrow under the influence of spring go. If the armature G* sticks while the
armature G³ moves away from the magnet the port 27 will still be open to the air
supply through port 25 and channel m³ and port 18, port 28 will also be connected
to the air supply through port 23, channel and port 21 hence equilibrium of
pressure will be established on the two sides of the piston J' and the spring g³ will
operate to open the valve as before. If when the coil F is energised by a current
one of the armatures G³, G' does not move it will be seen that the switch in the
supply wire cannot be closed for if the armature G' and valve M stick, port 18 will
be closed, the valve L moving with armature G³ will also close port 21 so that the
air supply will be entirely cut off from the cylinder J. If armature G³ and valve L
stick while valve M and armature G' move the air supply wili be conducted to
both sides of the piston J'since both ports 18 and 21 will be opened.
It will be seen from the above description that in order to close the supply
circuit it is essential that both of the armatures G³ aud G shall be attracted when
the coil F is energised and any sticking of one of the armatures or valves in either
position will either prevent the piston J' from moving or cause it to move so as to
open the switch, in any case the circuit through the supply wire will be broken
and the track terminal disconnected from the main.
A modified form of the apparatus is shewn in Figures 9 to 12 in which valves

page_text: such as shewn in Figures 7 and 8 are combined with a reservoir such as shewn
in Figures 5 and 6. The various connections are somewhat more complicated
than in the devices hereinabove described although the general principle remains the
same. The electromagnet G with its armatures G³, G' is arranged in a similar
manner to that shewn in Figures 7 and 8. The valves L and M have, however,.
the cavities to land m, m2. The cylinder H is provide with the ports 29 to 41.
The cylinder J which with the piston J' is substantially the same as shewn in
Figures 5 and 6 has the ports 45 to 53 provided as shewn, the piston J having
cross channels j, j and the cavity 2 as shewn. The ports 48, 49 and the cavity
are however not in the same axial plane as the port 47 hence when the piston
moves port 47 will not be connected with port 48 through the cavity. L', Mare
audible signalling devices connected to ports 29 and 36 to which ports is also
connected a visual signal device. A simple form of such visual signal is shewn
diagrammatically consisting of a piston L2 connected to an arm L³ and moving
according as the pressure of the air on one side is greater or less than that on the
other. The other ports are connected as follows:-Port 34 to port 45, port 35 to
port 43 and to the reservoir, port 37 to port 48, port 38 to port 42 and to port 50,
port 39 to port 41 and to port 46, port 40 to port 51, and port 44 to port 49..
Port 52 is connected to the air supply and port 47 to the reservoir.
In Figure 9 the apparatus is shewn in a normal position when no current is
passing through the electromagnet coil F. The connection between contacts g, gl
is broken and air from the main supply pipe can pass through port 52, channel j
and port 47 to the reservoir K. Ports 43 and 35 are both closed hence no air can
escape from the reservoir. If a current be sent through the coil F both the
armatures G³, G' are attracted and the valves take up the position shewn in
Figure 10. Air can now pass from the reservoir through port 43, cavity m³ and
ports 42 and 50 to the back of the piston J. The said piston is therefore caused
to move forward in the cylinder J compressing the spring g and connecting the
contacts of the switch by the bridge piece g2. As soon as piston J' has moved
forward a short distance the channel ; no longer connects ports 52 and 47 and the
air supply is therefore cut off from the reservoir. While the piston J' is moving
forward the air in front thereof escapes through ports 45, 34 cavity and port 33
to the atmosphere until the piston has nearly reached the end of the cylinder when
port 45 becomes closed. Just about this time the channel 71 connects port 47 to
port 51 whereupon air from the reservoir K passing through said ports and channel
and through port 40 cavity 1 ports 39 and 46 presses on the front end of the
piston J and since the area of this front end is greater than that of the rear end
the piston is driven back. The connection between ports 47 and 51 is thereby
broken through the removal of the channel and the piston again moves forward.
This backward and forward motion of the piston will continue until the total
pressure on the front end of the piston is equal to the total pressure on the rear
end of the piston. Since however the areas of the ends are not equal the pressure
in the front of the cylinder J will be less than the pressure at the rear end of said
cylinder, the rear end of the piston having the full air pressure from the reservoir
applied thereto. The approximate position of the piston when equilibrium has
been established in the manner above mentioned is shewn in Figure 10, the switch
being closed. When the current is cut off from the coil F the armatures G³, G
being no longer attracted normally resume the position shewn in Figure 9 in which
case port 50 is connected through port 42 cavity m² and port 41, and also through
port 38 channel port 39 to port 46 and the air in front of the piston is brought
to the same pressure per square inch as the air in the rear of the piston. The
total pressure on the front of the piston being greater than that on the rear end of
the piston then assists the spring g³ to force the piston to the rear and open the
switch.
So far we have considered the normal operation of the apparatus. If, however,
one of the valves L or M sticks the switch will either be opened or not permitted

page_text: to close, for example:-If the valves be in the position shewn in Figure 9 and the
valve M should stick when a current is passed through the coil F the valve L
alone will move. No effect will be produced on the piston J' since air cannot pass
from the reservoir to the port 50. If when the switch is closed in the position
shewn in Figure 10 and current is stopped in coil F the armature G³ should stick
and not move away from the magnet, the valve M under the action of its spring
moves beyond the centre of the cylinder H until stopped by the valve L. This
position of the apparatus is shewn in Figure 11. The port 43 is uncovered and
air under pressure will pass from the reservoir through ports 43, 29 giving an
audible signal at M' and also pressing upon the piston L2 and causing the signal
arm L³ to take up the position shewn in Figure 11. At the same time the space
at the back of the piston J' will be put into communication with the space at the
front of said piston through ports 50, 42, 41, and 46 whereupon the piston will be
moved back by the action of the air pressure and spring g' so as to open the switch
as hereinbefore described.
If now with the apparatus in the position shewn in Figure 9 the valve L sticks
and valve M alone is moved when a current is passed through coil Fair will pass
through port 43 channel m² and ports 42 and 50 to the back of the piston J. At
the same time however port 50 will be connected through port 38 cavity 14 and
port 39 to port 46 hence air at the same pressure will be admitted in front of the
piston which will not move. If however, when the piston is in the position shewn
in Figure 10 the valve M or armature G₁ sticks when current is cut off from
coil F, the valve L will move beyond its ordinary central position to the position
shewn in Figure 12 whereupon port 35 will be opened and air under pressure from
the reservoir will cause an audible signal to be given at L' and pressing on the
piston L2 will push it to the end of its cylinder causing the indicating arm L³ to
take up the position shewn in Figure 12. The reservoir will also be connected
through port 43 cavity m² and port 42 to port 50 and through port 38 cavity 1 and
port 39 to port 46 hence the air pressure will be the same on both sides of the
piston J which will consequently be pushed to the end of its cylinder under the
influence of the air pressure and spring go thereby opening the switch.
It often happens that the jarring of one valve taking up unusual positions in
the cylinder H which movement if the valve is assisted by the air pressure as
hereinabove described when the other valve sticks will cause the latter valve to
move if the obstruction is not a very serious one. Said valve cannot move however
until the pressure at one end of cylinder H is equal to the pressure at the other
end thereof and this will not happen until and as soon as the piston J¹ has moved
to the rear end of the cylinder J when the ends of the cylinder H will be connected
through ports 44, 49, channel j, ports 48 and 37 thereby placing the valves under
equal conditions as regards air pressure. The audible signal will continue to sound
until the apparatus is caused to assume its normal position.
Referring now to Figure 13 a system of connections is therein illustrated
whereby when a car reaches a series of terminals the current is caused to flow
round an electromagnet which actuates the switch to close the connection between
the main and all the terminals in the series. This electromagnetic switch may
be combined with an automatic circuit breaker if desired. This connection is
maintained whether the switch magnet continues to be energised or not until the
car reaches the end of the series of terminals when another magnet is energised
which breaks the connection. It will therefore be seen that it is not necessary to
maintain a current flowing round a switch magnet during a whole period of time
when the car is passing over a series of terminals. The terminals are denoted by
the letters A, A¹ etc., all the terminals in one series being denoted by the same
letter and numeral. The electromagnetic switch which is shewn for controlling
current in the supply wire leading to the series of terminals A¹ has two coils N, N
and is so arranged that when a current is sent round the coil N the switch lever is
moved owing to the attraction of the armature N2 so as to make the circuit in the

page_text: , which
supply wire c. When the coil N' is energised the armature of the switch being
attracted in the opposite direction actuates the lever to break the connection in
the supply wire. The switch lever is weighted and balanced in such a manner
that after once being attracted in either direction it remains in that position until
attracted in the opposite direction notwithstanding the fact that the current
through the electromagnet may have been stopped. For the purpose of sending
currents through the electromagnet coils N, Ni when necessary the terminals of
said coils are connected to exposed terminals n, n, n', n' and a battery is carried by the
car connected to brushes also carried by the car which brushes make contact
with the terminals n or n' as the car moves along thereby sending a current
through the coil N or N¹ from the battery on the car. The terminals n..
I will call the "energising" terminals will in general be placed in the track
so that the car reaches them some little time before reaching the first of the
terminals in the series of track terminals which it is approaching, and the de-
energising terminals n¹ n' will be placed in advance of the last terminal of the
same series of track terminals. In this arrangement it will be observed that each
series of track terminals forms a section of the line all the terminals in the section
being connected simultaneously just before the car reaches the section and
becoming disconnected from the main as soon as the car reaches the last terminal
of the section. In order to ensure that the car shall always receive current the
energising terminals of one section are generally placed in the track some little
distance before the de-energising terminals of the previous section. In some cases
it may be advisable to use polarized armatures on the switch lever so that the
movement thereof and consequent opening and closing of the circuit in the supply
wire depends on the direction of the current sent from the car battery in these
cases also one electromagnet only is in general required. When this arrangement
is employed to control a series of terminals each terminal of the series may be in
addition fitted with an ordinary electromagnetic switch controlling the supply of
energy thereto.
In Figure 14 I shew an improved device for preventing accidents due to the
sticking of an electromagnetic switch. F is the magnetic coil of a well known form
of electromagnetic switch similar to that described in the Specification of British
Letters Patent No. 16659 dated 5th September, 1895. g, gl are the contacts and
92 is the bridge piece of the switch. In addition to the ordinary armature which
is attached to the bridge piece g² 1 provide a second armature attached to a bridge
piece O which is adapted to connect the contact O' with the contact 02 said contacts
being connected to the outgoing and returning mains respectively. The connection to
one of the mains is made through the bridge piece g². The bridge piece o is
normally operated by means of a spring O³ so that the contacts 0', 0' are
connected. The mains will not, however, be short circuited because the contact g
is not connected to contact g¹; when, however, the coil F is energised both
armatures will be attracted and connection will be made between contacts g g' and
at the same time the short ci. zuiting connection will be broken by the withdrawal
of bridge piece O from its contacts. When the current is cut off from coil F the
bridge piece O rises and connects the contacts 0 and O¹, and if the bridge
piece g² sticks and maintains connection between the contacts g, g¹ the mains will
be short-circuited.
This will, however, cause the ordinary automatic circuit
breaker to act and break the circuit so that no damage will ensue.
In electric traction systems operated by alternating currents with transformers
I sometimes divide the track into sections of a suitable length, each section having
a series of terminals or groups of terminals to supply current to a car as it travels
on the section, a transformer for such current supply and a continuous rail herein-
above called E by means of which one pole of the car battery is connected to the
wire leading to the automatic switch magnets. In Figure 15 I have illustrated one
section of such a track.
P, P are the primary mains, P¹ the primary coil of the transformer belonging to
B

page_text: the section, and S the secondary coil. The ends of said secondary coil are con
nected through each of the track terminals A to an automatic electromagnetic
switch of any suitable type such for example as hereinabove described. The other
ends of the secondary coil is connected to a rail or series of exposed terminals
upon which runs a brush or trolley wheel or equivalent device carried by the car.
The coil F on each electromagnet is energised in the usual manner from a battery
carried by the car.
So far the system is similar to that described with reference
to Figure 1 the switch being placed in the secondary circuit. As an additional
element of safety, however, I place a switch in the primary circuit said switch
being controlled by an electromagnet the coil pl of which is energised by the car
battery through the wire p².
The operation of the system is as follows:-
When a car enters a section contact is made with rail E and with the first track
terminal of the section by the contact bars or brushes connected to the car battery.
By this means the current is caused to flow through coil F on the electromagnet
appropriated to the first track terminal and also through the coil p' of the said
switch in the primary of the transformer appropriated to the section. The
primary circuit is therefore made and also the secondary circuit connected to the
first track terminal. When the car leaves the first track terminal and passes over
a second track terminal the primary circuit is made as before and the secondary
coil connected to the second track terminal. As soon as the car leaves the section
current can no longer flow through the coil p¹ from the car battery, consequently
not only are the track terminals of the section disconnected from the secondary
wires, but the primary coil is disconnected from the primary mains. Hence if a
section of the line be empty of cars not only are all the track terminals dis-
connected from the secondary of the transformer, but the primary circuit of said
transformer is also broken. A double element of safety is therefore obtained.
The switch p in the primary circuit may be combined with an automatic circuit
breaker if desired.
This principle may also be applied where the line is operated by direct currents
the feeder of the lead supplying a series of terminals forming the section of the
line being adapted to be made and broken when a car enters or leaves said section.
Another method of operating where alternating currents are used for supplying
power to the car is illustrated diagrammatically in Figure 16. The battery D or
its equivalent is joined in series with an inductive resistance D' across the
terminals of the car motor Q which are connected to the contact bars B, B. The
electromagnet coil F which operates the automatic switch has also inductive
resistance F in series with it and is joined across the exposed terminals A, A
of the track. The secondary S of the transformer is connected to the track
terminals A, A.
It will be readily understood that when the car is over a pair of track
terminals A, A so that bars B, B make contact with said terminals a current will
be sent from the battery D through coil F and energising the switch magnet
causes the secondary coil S to be connected to the terminals A, A. Alternating
currents will therefore be supplied to the car motor Q. These currents will not
however pass through the battery D or magnet coil F because of the inductive
resistances D¹ and F.
When alternating currents are used for operating the line I sometimes employ
in place of a battery carried by the car a transformer supplied from the main
current for operating the switches. Said transformer takes the place of the motor
generator described in the Specification of British Letters Patent No. 16659 of
1895 herein before referred to.
In Figure 17 I shew an improved arrangement of switch box in which the
exposed terminal A with its insulating block a is used as a covering for the box.
The track terminal may be connected to the switch magnet through a pin and 5
socket connection in the manner described in the specification above referred to so

page_text: that when the switch mechanism requires to be inspected it is only necessary to.
lift the terminal and base from the rod.
Having now particularly described and ascertained the nature of my said inven-.
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In an electric railway of the class described, a contact bar or shoe carried by
the car and constructed of two or of three insulated parts placed end to end and
co-operating with a single series of track terminals, one or two of said parts.
conveying current for actuating the automatic switches from a battery or its
equivalent carried on the car and the other of said parts conveying current from
the main through the track terminals to the car motor.
2. In an electric railway of the class described, an automatic switching device in
which the switch is actuated by compressed air or other fluid, and is provided with
means whereby the same body of compressed fluid which operated to close the
switch also operates to open the switch, no further supply of fluid being required.
for this purpose.
3. In an automatic switch actuated by fluid pressure for use in railways such as
described, a valve for controlling the supply of fluid to the switch mechanism, said
valve having two independent moving parts so arranged that movement of both.
parts is required in order to permit closing of the switch.
4. In an automatic switching device in which a piston is moved by compressed
fluid to operate the switch, the provision of a reservoir for the compressed fluid.
and means whereby when the piston moves so as to close the switch the said
reservoir is cut off from the main supply of compressed fluid, for the purpose
specified.
5. In electric railway systems of the class described and operated by means of
alternating currents and transformers, the provision of means for breaking the
primary circuit of the transformer as well as the secondary circuit in order to cut.
off the supply of energy to a track terminal.
6. For electric railways, switching devices constructed and operating sub-
stantially as described with reference either to Figures 5 and 6 or to Figures 7*
and 8 or to Figures 9 to 12 of the accompanying drawings.
7. The electric railway systems described with reference to either of the
Figures 1, 2, 3, 4, or 13 of the accompanying drawings.
8. In railways of the class described, an automatic electromagnetic switch
provided with means for short-circuiting the mains when, the current being cut off
the electromagnet, the switch does not disconnect the track terminal from the
main, substantially as described.
9. In electric railways of the class described wherein each one of a series of
terminals forming a section is connected to a subordinate supply wire joined to the
main lead, the provision of means whereby the subordinate wire is disconnected
from the main as well as from each track terminal when no car is on the section,.
substantially as described.
10. Electric railway systems operated with alternating currents as described
with reference to Figure 16 of the accompanying drawings.
11. In railways of the class described a track terminal which with its insulating
block forms the cover of the automatic switch box as described with reference to.
Figure 17 of the accompanying drawings.
ה: נ..
1006
W. P. THOMPSON & Co.,
322 High Holborn, London, W.C., Patent Agents for the Applicant..