Improvement in Automatic Systems of Preventing Collisions on Electric Railways.
Year: 1899

page_text: Date of Application, 14th Mar., 1899-Accepted, 29th Apr., 1899
COMPLETE SPECIFICATION.
Improvement in Automatic Systems of Preventing Collisions on
Electric Railways.
We, CHARLES FOSTER BANCROFT, of 50, Chelmsford Street, City of Lowell, in
the County of Middlesex, and Commonwealth of Massachusetts, one of the United
States of America, Electrical Engineer, and PATRICK FRANCIS SULLIVAN, of
Waverly Avenue, in said Lowell, Street Railway Manager, 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: —
This invention relates to automatic systems of preventing collisions on electric
railways, and consists principally in means whereby the passing of a car along a
section of line will shut off the power from another section of the same.
This invention is particularly applicable to a single line track provided with
turnouts, of any usual construction, on which cars may pass each other in opposite
directions, it being understood that the car going in the same direction, always
keeps at the same side of the turnout.
The general adoption of this invention would render travelling on single lines
less dangerous to the public and less costly to the owners of the railways.
In the accompanying drawing, on three sheets, Fig. 1 is a diagrammatic plan
of a dynamo and a conducting system or line, representing three turnouts, provided
with our improvement; Fig. 2, a side elevation of an electric car carrying a
trolley, part of a trolley-wire and a longitudinal section of a conducting or
contact plate, insulated, from said wire and adapted to form with said trolley a
circuit-closer; Fig. 3, a side view of the trolley-wire, contact plate and trolley :
Fig. 4, a cross section of the trolley-wire and a rear elevation of the trolley, the
upper part of the trolley-pole, the contact plate and a hanger; Fig. 5, a cross
section of a modification of said plate and wire and a rear elevation of the trolley
and upper part of the trolley-pole; Fig. 6, a front elevation of a post with feed-
wire, a feed tap and wire from contact-plates, feed-wire for a turnout section
of the trolley-wire, and automatic switch-box; Fig. 7, a front elevation of the
switch and its base; Fig. S, a side elevation of said switch and base.
+
The car A (Fig. 2) is of any usual construction, in which the current is taken
from a trolley-wire T by a trolley a, brush or equivalent device, and pole a¹,
through an electric motor (not shown) carried by the car, and through the wheels a³
and by the rails, indicated in Fig. 2 by line B, or by a return-wire R (Fig. 1) to
the dynamo or other electric source. The track forms no part of our invention
and is not herein shown, except as above stated.
The trolley wire T, feed-wires F, feed-wire taps ffl. return-wire R, dynamo D,
and turnouts T T 13, are all of any usual construction.
In each turnout the branches or sides are in separate sections from the
cud-portions or frogs, being electrically separated from and mechanically con-
nected to said frogs by section-insulators of usual construction, indicated by
breaks at (see Five 11.
.

page_text: Parallel with each branch of each frog and in close proximity thereto but
insulated therefrom, is arranged a plate C or C of conducting material (Figs. 2,
3, 4, 5), against which the trolley-wheel presses in passing, (the trolley wire
between the ends of said plate yielding upward as shown in Fig. 3) and closes
a circuit from the trolley-wire through a switch-box S S S S S to the return-
wire R, there being at each turnout such a switch-box, as shown in Fig. 1.
The construction of each switch-box is shown in Figs. 6, 7 and 8. Each switch-
box contains, supported on a non-conducting plate or bases, a pair of sole-
noids M N surrounding a core O common to both solenoids, to which core is pivoted
a lever o, the fulcrum o' of said lever being also secured on said base and said
lever being electrically connected, as by wire to the adjacent branch & or t
of the nearest turnout, said wire being connected directly to the fulcrum o as
indicated in Fig. 1, or to a conducting plate o, over which said lever swings and
with which said lever is always in contact, as indicated in Fig. 7.
When the lever o is in the position indicated in Figs. 1 and 7, its free end
rests on a contact of a supplementary feed tap 2, thus connecting the feed-
wire F to the branch or through the wire 2, lever and wire . When the
lever is moved by the action of the solenoid N on the core Ú and opens the
line ov, the corresponding branch or is dead.
The cars are supposed to be passing from and towards the power station or
dynamo D and keeping to the right on the turnout. As the first car out from the
power station passes the contact plate C of the first turnout T the circuit is
closed from the trolley-wire or frog (which is a part of said trolley-wire) through
the trolley, said plate C, line c, solenoid M (of the switch-box S¹) and line to the
return wire, leaving the lever o in the position shown in Fig. 1 at said first turn-
out T. The car will proceed over the branch t (if the lever o of the switch-box St
is in the position shown) and passing the contact-plate C will close a circuit from
the trolley wire or frog through wires e c¹ to the solenoid N of the switch-box S¹
at the right of the first turnout T" and by wire to the return wire R, thus
energizing said solenoid, moving the corresponding lever o and rendering the
branch t, which the trolley has just left, dead, and by a similar circuit, marked
with corresponding letters of reference, energizing the solenoid N of the switch-
box S, at the left of the next turnout in advance, and breaking the line to
the branch of the turnout T2, thus making said last named branch dead.
As the car proceeds, at each turnout the trolley branch at the right is thrown
out of circuit after the trolley leaves it and simultaneously, the trolley-branch on
the left of the next turnout in advance is thrown out of circuit.
When in the progress of the car, the trolley comes in contact with the switch-
plate Cat the right of any turnout T or T, after the first, a circuit is closed
through the solenoid M at the left of that turnout, as above described with relation
to the first Turnout T, but, by wires the magnet M at the right of the turnout
last passed is energized to move the corresponding lever and to connect the dead'
branch of the last named turnout with the feed-wire.
When the car having reached the end of the line returns, the same operation is
repeated, the terms right and left still applying to the motor-man who faces in the
direction in which the car moves and therefore to the car.
It is evident from the foregoing that when a car has passed over a branch of
a turnout no car can enter on said branch until the car in advance has reached the
next turnout and that no car can approach it in the opposite direction nearer
than the next turnout.
A convenient way of supporting and insulating the contact-plates CC is by
means of insulating hangers of common form such as are used for span-wire
clamps and insulator holders and I prefer to make said plates of the form of angle
plates as shown in Fig. 5, with the external angle on top, to prevent the lodgment
of ice or snow thereon.
At each turnout cach branch may be connected with the return-wire by a
local circuit containing an audible or visible signal, thus; in Fig. 1. a light

page_text: circuit is shown at L the light being extinguished when the branch is dead or out
of circuit and glowing at other times, thus indicating to the motorman that the
power is off and warning him not to enter on the dead branch for fear of putting
out the electric lights on the car or of shutting off the heaters or leaving the
car without power to move in case of accident or other necessity.
It is evident that with this invention there can be no collision between cars
approaching the section between the turnouts, except in the rare case where the
trolleys of two cars simultaneously operate corresponding contact-plates, unless the
cars were carried across the insulated section by their own momentum, but to
guard against even this source of danger; we use an additional contact-plate C,
arranged at the entrance of the turnout, at the right of a car approaching the
turnout, and an additional solenoid N' is arranged to operate the lever o, to cut
off the current from the middle, or insulated section on the opposite side of the
next turnout, making it impossible for another car to leave the insulated section
of said last named turnout, if the first named car had already entered upon the
insulated section of its own turnout, thus making a collision impossible. It will
be understood that the solenoid N is electrically connected to the return-wire R
by the wire and to the contact plate C3 by the wire ³, and that the contact-
plate is like the contact plates C and that the solenoid N¹ is like the sole-
noid N.
It is obvious that where one track of a double track is discontinued tem-
porarily for repairs, on account of less travel or because of the expense and
difficulty of keeping both tracks open, and a comparatively short section of
track is connected to the other track hy cross-overs, said short section and cross-
overs constitute in effect a turnout and in such cases corresponding turnouts are
formed in the wire and the above described invention is applicable as well as
where two parallel tracks are continued in a single track.
Having now particularly described and ascertained the nature of said
invention, and in what manner the same is to be performed, we declare that what
we claim is: -
1. The combination in an electric railway, of a feed-wire, a trolley-line, provided
with turnouts, having in each branch an insulated section, and means whereby
the moving of a trolley or equivalent device over one branch of one of said turn-
outs will render the insulated section of the opposite branch of the next turnout in
advance dead and prevent an approaching car from passing over said last named
turnout.
2. The combination in an electric railway, of a feed-wire, a trolley-line, provided
with a turnout, having an insulated section in each branch thereof, and means
whereby the moving of a trolley or equivalent device over a branch of one of said.
turnouts will leave the insulated section of said branch dead and prevent a
following car from passing over said turnout.
3. The combination in an electric railway, of a feed-wire, a trolley-line provided
with turnouts having in each branch an insulated section, and means whereby the
moving of a trolley or equivalent device over a branch of one turnout will render
dead said branch and the opposite branch of the next turnout in advance and
prevent any car from passing onto the line between said turnouts.
4. In an electric railway, a return-wire, a single trolley-line, having turnouts,
provided with insulated sections, feed-wires, in circuit with the sections between
said insulated sections, contact plates, insulated from said last named sections but
adapted to be electrically connected therewith by a trolley or equivalent conducting
device passing along said contact plates, electric switches, electric conductors,
connecting said feed-wire and said insulated sections through said switches, and
electric circuits, including said contact plates, and means for operating said
switches, to open or close said switches.
5. The combination in an electric railway, of a feed-wire, a single trolley-line,
having turnouts, each provided with an insulated section, a switch, in circuit

page_text: between said feed-wire and said insulated section at one turnout, and another
circuit normally open, means, arranged in said last named circuit, for operating
said switch and a circuit-closer, arranged in said last named circuit at another
turnout.
Dated this 14th day of March A.D). 1899.
CHARLES FOSTER BANCROFT.
PATRICK FRANCIS SULLIVAN.
By Herbert Haddan & Co.,
Agents to Applicants,
18, Buckingham Street, Strand, W.C., London.