Improvements in Electric Surface Contact Railway Systems.
Year: 1898

page_text: Date of Application, 4th Oct., 1898-Accepted, 5th Nov., 1898
COMPLETE SPECIFICATION.
Improvements in Electric Surface Contact Railway Systems.
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,
residing at Schenectady, County of Schenectady, State of New York, United States
of America, 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 surface contact railway systems; and has for its object
to provide a safety device for such systems, which will indicate definitely whether
or not a contact over which the car has just passed has been left "alive" in the
street. In many of these systems, there is a possibility of contacts being left
alive, with consequent danger to persons and to animals. It has been proposed, as
a safety device, to so arrange the motor contacts that a supplemental shoe or
brush from the car shall touch them and short-circuit the contact to ground; in
this short circuit would be inserted a fuse which should blow by the passage of the
abnormal current, although it would carry the ordinary motor current. The
disadvantage of this is that the sectional conductor or contact would be killed, and
it is necessary to make repairs; yet there would be no indication given of the
trouble to the crew on the car, which would ordinarily go over a single dead
contact in an efficient system without indication. Furthermore, if the car should
stop when over this contact, it could not start again.
In another system it has been proposed to demagnetize the switch by a supple-
mental shoe or contact and thus insure its opening. This, however, is open to
the same objection, that a defectively operating switch would not be indicated
and repairs would not be made.
By this invention these difficulties are obviated by providing upon the vehicle
an automatic circuit-breaker of any convenient type, having its actuating magnet
connected between the ground and a supplemental or testing shoe, which will
make contact with the sectional conductor after the shoe furnishing motor current
has left it. With the circuit-breaker may be combined, any convenient visual
or audible signal, though ordinarily the failure of current caused by its opening
would be sufficient. Also combined with it is a registering device showing
whether it has been opened; this device is preferable out of control of the motor-
man, so that the car inspector may be able to determine how often the circuit-
breaker has been actuated.
This invention is illustrated in diagram in the accompanying drawing. In
this drawing, A, A are the track rails, H the feeder, B, B1, B3 and B3, the surface
contacts or studs furnishing current to the motor. C, C1 and C2 the studs upon
the negative side actuating the electro-magnet switches G, G¹ and G2 which

page_text: connect the feeder with the positive contacts B, B1, B2 and B3 in sequence as the
car passes. I, I¹ are the supplemental or testing contacts referred to, which are
independent of the shoes F, F1 carrying the working current. D, D¹ are the car
wheels, M, M the motors. E is a storage battery, the use of which in these
systems is well understood.
In the ordinary operation of the railway, the parts act as follows: when the
shoe F touches the contact C (passing to the left), a portion of the motor current
passes down and actuates the switch G, closing the circuit between the feeder H
and the stud B. In case the motor current be cut off so that all the switches are
down, when the car starts, the current from the battery E is passed through the
shoe F¹ and the switch button upon which it rests, to ground, picking up the
switch. In the lead from the shoe F to the motors is a circuit-breaker K, consist-
ing of contacts k, k, and an arm carrying a bridging contact k¹. A blow-out
magnetis indicated, and is arranged adjacent to the contacts, which may be of
the form shown, or of any other convenient one. The circuit-breaker as just shown,
however, is not designed to act by abnormal current flowing in the motors. The
arm K¹ is held in place by a detent N, which operates the registering mechanism P.
At back contacts upon the circuit-breaker complete the circuit of a battery
and a bell L, so that when the circuit-breaker K opens, the bell L rings until it
is closed. The series operating coil O of the circuit-breaker is in circuit between
the shoes I, I¹ and ground. These shoes should be at such a distance from the
shoes F, F carrying the working current, that they will never be in contact with
any one of the studs B, B or B2 when the shoe F¹ is upon the corresponding
switch button C, C¹ or C³. As indicated in dotted lines, the displacement may
be in either direction, provided this result is attained.
The operation of the parts thus described is as follows: suppose that the switch G
as indicated in dotted lines remains closed after the car has gone towards the
right, leaving the button or stud B alive. Current will then flow from the stud
through the series coil O to ground, pull down the detent N and open the circuit-
breaker, completing the circuit of the battery 7 and ringing the bell L. This will
indicate the presence of the live button; but in the meantime the car would of
course have passed on, and it would be impossible to determine which one of the
buttons was touched by the brush when the circuit-breaker opened. When the
current failed, however, the motorman would reverse the car after bringing it to
a stop, and back it slowly until the brush made contact with the live button, when
the circuit-breaker would again open and the location of the defective switch
could be at once ascertained. When running in the opposite direction the brush I'
would serve the same purpose as the brush I.
While the apparatus might be installed in any ordinary car, it would be most
conveniently located in a testing and repair car, which would be run over the road
from time to time.
Having now particularly described and ascertained the nature of our 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 surface contact railway, a feeder, sectional conductors or studs
arranged in two sets, one furnishing current to the motor, and the
other upon the negative side of the system, and electro-magnetic, con-
necting switches; in combination with a moving vehicle carrying motors,
sliding contacts upon the vehicle for each of the sets of sectional conductors, à
testing contact in the line of the positive studs and in circuit with a circuit-
breaker upon the vehicle in the main motor lead, and a registering apparatus
actuated by the circuit-breaker.
2 In a closed-conduit or surface contact railway, a feeder, sectional conductors
or studs arranged in two sets, one furnishing current to the motor, the other
upon the negative side of the system, and electro-magnetic connecting switches;
in combination with a moving vehicle carrying motors, sliding contacts upon the

page_text: vehicle for each of the sets of sectional conductors, a testing contact in the line
of the positive studs and in circuit with a circuit-breaker upon the vehicle in the
main motor lead, and an indicating device actuated by the circuit-breaker.
Dated this 4th day of October 1898
THE BRITISH THOMSON-HOUSTON Co. LTD.
W. MARTINDALE,
A. R. MONKS,
i:
Directors.
ALFRED CLEMENTS,
Assistant Secretary.