IMPROVEMENTS IN ELECTRO-MAGNETIC RAILWAY SIGNAL APPARATUS
Year: 1873

page_text: LETTERS PATENT to George Haseltine, of the "International Patent
Office," Southampton Buildings, London, Doctor of Laws, for the
Invention of "IMPROVEMENTS IN ELECTRO-MAGNETIC RAILWAY SIGNAL
APPARATUS."-A communication from abroad by Thomas Sheppard
Hall, of West Meriden, Connecticut, Manufacturer, and Abram
Lines Van Blarcom, of Summit, New Jersey, Merchant, both of
the United States of America.
COMPLETE SPECIFICATION filed by the said George Haseltine at the
Office of the Commissioners of Patents, with his Petition and
Declaration, on the 10th October 1873, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
•
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
HASELTINE, of the "International Patent Office," Southampton
Buildings, London, Doctor of Laws, send greeting:
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
ELECTRO-MAGNETIC RAILWAY SIGNAL APPARATUS," and have petitioned Her

page_text: Majesty to grant unto me, my executors, administrators, and assigns,
Her Royal Letters Patent for the same, and have made solemn
Declaration that it has been communicated to me from abroad by
Thomas Sheppard Hall, of West Meriden, Connecticut, Manufacturer,
and Abram Lines Van Blarcom, of Summit, New Jersey, Merchant,
both of the United States of America.
NOW KNOW YE, that I, the said George Haseltine, do hereby declare
that the following Complete Specification under my hand and seal fully
describes and ascertains the nature of the said Invention, and in what
manner the same is to be performed in and by the following statement,
reference being had to the accompanying Drawings forming a part of
this Specification :-
This Invention consists in a series of signal houses arranged in pairs
alongside a railway in combination with two line wires, which extend
from a battery along the line, and which-connect with electro-magnets
in the signal houses, and with track instruments which are situated near
the rails in such a manner that. one and the same. battery serves to
vitalize the electro-magnets in each of the whole number of signal
houses whenever the wheels of a passing train act on the corresponding
track instruments. Also in the combination of signals of safety, with
signals of danger arranged on the line of a railway in pairs, the two
signal houses-constituting each pair being, placed about six: hundred or
one thousand feet (more or less) from each other; such signals are
operated alternately by electro-magnetism and by gravitation in such a
manner that the safety signal indicates danger. whenever from some
cause the battery should fail to work, or one of the connecting wires
should be broken, and unless the signal- of danger thus displayed is
disregarded by the engineer all danger of a collision is avoided. Further,
in the arrangement of a locking lever in combination with each signal,
the said locking lever being attached to or connected with the armature
of an electro-magnet- in such a manner that by said locking lever the
signal is securely retained in the position into which it is brought
whenever its signal magnet. is vitalized, and it (the signal) is not
permitted to reassume its position of rest until the electro-magnet of
the locking lever is vitalized. Also in the combination of a piston with
the key lever of a circuit closing instrument, and with a track lever in
such a manner that when the piston is forced upwards to operate the
Key lever an air cushion is formed in the cylinder, which-prevents- the

page_text: piston from being slammed against the cylinder head. In the cylinder
are formed air passages, which promote the formation of the required
air cushion, and an adjustable valve controls the passage of the air from
the lower to the upper part of the cylinder, so that the descent of the
piston is retarded and the circuit is held closed for a certain period of
time after the train has passed the track lever.

page_text: "
an adjustable balance weight p; the signal h may be termed "danger
signal. From the hub of the lever extends a chain i to an arm j
projecting from a rock shaft k, on which is mounted a second arm ↳
connected by a rod m with the armature lever n of an electro-magnet o..
If the armature is attracted the rod m is forced upward, and the signal
lever is turned on its pivot so as to bring the signal disc opposite the
aperture e, and consequently the signal is displayed, but as soon as the
armature of the electro-magnet o is permitted to fall back the signal
disc which somewhat overbalances the weight p will, if not otherwise
detained, return by its inherent gravity to the position shewn in Figure 2,
and the signal is taken off.
The signal houses S, S¹, are constructed like the signal houses D, D',
but the signals ª contained in the same when permitted to follow their
adherent gravity drop down before the apertures e in their signal houses,
and if they are raised by the action of their electro-magnets o* they
disappear, or in other words, they shew safety, while the signals / in the
houses D', D', and so forth, when actuated by their electro-magnets o,
show danger, and when left to follow their inherent gravity they show
safety. The signals may therefore be termed safety signals, while the
signals h are termed danger signals as previously stated. The electro-
magnets o, o* of the signals h, h, are vitalized by the action of the
wheels or other parts of a passing train on the track instruments a, b, a¹, b¹,
and in order to retain the signals in position for some time after the
train has passed they are locked by levers f³, f, in the following
manner :—The locking levers f of the danger signals h (see Figures 2
and 4) are situated in such a position that they act on the tail ends of
the signal levers or rods g, and they are exposed to the action of a
spring, which allows the same to recede as the rods g sweep down in
front of them, and when the rods have passed the ends of the locking
levers the latter spring back and hold the signals displayed. Each of
the levers f" is connected to the armature of an electro-magnet *, and
the signal is kept displayed until this electro-magnet is vitalized,
whereby the lever f³ is drawn.back so as to release the rod of the signal and
allow the latter to follow its inherent gravity and to return to its position
of safety. The locking levers f** of the safety signals 6 act directly on
the armature levers n of the signal magnets o*, and they carry the
armatures of electro-magnets ** (best seen in Figures 5 and 6), so that
when the armature levers n are locked by the levers f** the signal ª

page_text: will be retained out of sight, and they will be held in that position until
the electro-magnets are vitalized, whereby the locking levers fo* are
caused to release the armature levers n, and the signals are permitted
to follow their inherent gravity. and fall back to their position of
danger.
In each of the danger signal houses D, D¹, D³, is a key i, the object
of which will be presently explained.
The construction of the track instruments will be fully understood.by
reference to Figures 7 to 10 inclusive. In these Figures A° designates
one of the rails of a railway track, and B° is a track lever moving upon
a fulcrum 0°; and so arranged that its outer end is near enough to the
rail to be depressed by the wheels of passing trains, the lever being'
raised again and held up after the train has passed, by by a spring D°.
The outer end of the track lever also rests upon a spring E° within a
chamber Fo, into which the track lever extends through a holo G° in its*
side, which hole is covered to exclude dust by a sliding cover H° mounted
on the track lever, and in this example consisting of a thin clastic
plate a° of metal surrounding the lever just outside the hole G°, and
large enough to overlap its edges in all positions of the lever. The
plate a is held up against the walls of the chamber F° by a rigid
plate 6° that also surrounds the lever, and is kept in place by a pin cº.
A thin sheet of india-rubber d is interposed between the inner and
outer plates a°, bº.
The outer end of the track lever is directly under the lower end of the
3 piston rod 1° of a piston Jo, which works in a vertical air chamber or
clyinder K°; the upper end of the piston rod extends up through the top
of the cylinder as shewn, so that when the piston is in its lowest position
the track lever, being at rest, the upper tapering end of the piston rod
occupies the opening in the cylinder head through which it passes; its
O point protrudes just far enough to form a stop to the beveled key lever
L°, which is pressed against the tapering point of the piston rod by the
spring key M° of the circuit closing apparatus. The key lever L° is
pivoted on the top of the cylinder K° between the piston rod and the
spring key M°, and one end of the said key is put in connection with one
5 of the poles of an electrical battery through the wire eº, while its other
end is so arranged with respect to the anvil that it will be brought in
contact with said anvil by the operation of the key lever whenever the

page_text: piston rod is raised far enough to take its tapering end above the bevolled
edge of the key lever, a stop fo limits the extent of movement of the
key lever. The part of the said key lever, which comes in contact with
the key, is insulated by means of india-rubber 9° or other suitable
material.
. The piston rod is fitted accurately in the holes in the ends of the
cylinder to prevent the free passage of air as much as possible, and yet
allow the casy movement of the piston rod.
•
The wall of the cylinder K° is provided with two air passages, one of
which, 0°, opens into the cylinder at its lowest part, and the other, P°,
opens into the cylinder a little below its top, both passages being made
to extend through the top of the wall of the cylinder, where they are
intersected by a groove Q° formed on the under side of the upper head
of the said cylinder. The upper end of the passage P° is provided with
a valve R°, which plays between collars on a screw valve stem S°
screwed through a tapped hole. To extending up through the said
cylinder head, so that the valve stem can be screwed up or down to
adjust the valve. The valve stem is turned and locked by means of a
pin U°, which goes through it above the head, and serves as a handle
wherewith to turn it, and it is locked by inserting its bent end into one
or another of the depressions V°, provided for that purpose on the upper
surface of the cylinder head, as indicated in Figure 8. The valve R° is
so arranged that the air which is forced upwards by the rising piston is
allowed to pass out through the passage 0° into the horizontal passage
Q° and down through the passage P° into the part of the cylinder below
the piston, the valve opening readily to and rising on its stem; but in
order to prevent the rapid return of the air through the said passages
when the piston descends I adjust the valve by means of its screw stem
in such a manner that it is nearly closed upon its seat, and the air is
allowed to pass into the passage 0° slowly, the pressure of the air on the
back of the valve keeping it down as near to its seat as the adjustment
of the valve stem permits. The position of the mouth of the passage
0° in the side of cylinder K° causes an air cushion to be formed between
the piston and the upper head of the cylinder as soon as the piston has
passed the mouth of that passage, and as the piston rises above that
point the air, thus confined, becomes compressed and forms an efficient
air cushion, which prevents the piston from slamming up against the
cylinder head.

page_text: It will be observed that from the construction and arrangement of the
parts the key lever will be pushed by the piston rod against the key to
close the circuit immediately after the piston begins its upward move-
ment, and that the continued upward movement of the piston will carry
the top of the piston rod a considerable distance above the key lever,
the side of the piston rod meanwhile, throughout its whole ascent, press-
ing against the key lever so as to keep the circuit closed. In order still
further to prolong the time the circuit is kept closed, and to prevent its
being suddenly opened after the fall of the track lever, the air below the
piston is controlled in its return to the upper part of the piston. by means
of the valve R°, which can be adjusted as described to retard the return
of the air under the pressure of the falling piston, and cause the piston
and piston rod to fall more or less slowly; the key M° is thereby kept
pressed against the anvil a longer or shorter time as may be desirable.
The top of the cylinder is provided with a close fitting cap to protect
the circuit closing apparatus, and the wires e°, e¹º, are led through a
suitable tube to the battery.
All the signals on the line are operated by one and the same battery
B, which is situated in the depot or station house at one of the termini
of the road. One pole of this battery connects with a line wire 11, and
the other with a line wire 12 which extend from one end of the line to
the other.
If a train moves on the track A in the direction of the arrow shown
thereon in Figure 1, and if the wheels of this train strike the lever of
the track instrument a the circuit is closed through wires 11 and 13,
track instrument a, electro-magnet o of danger signal D, and wires 15
and 12 back to the battery. The electro-magnet o is vitalized, and the
signal in the house D is raised into sight. The tail end of the signal
lever g on striking the key i closes the circuit through wires 11 and 13
and 16, key i, wire 17, electro-magnet o* of signal house S, and wires
18 and 12 back to the battery; the electro-magnet o* is vitalized, and
the safety signal hª is moved out of sight.
.
The signal is locked in its raised position by the lever f², which
however allows the rod to recede sufficiently to relieve the key i, so that
the circuit through the electro-magnet o* of the safety signal S is broken
as soon as the signal is moved out of sight. The locking lever f*
retains the safety signal in position.

page_text: As the train proceeds its wheels strike the lever of the track instru-
ment a¹, and the signal D' is brought in sight, while the signal S' is
moved out of sight before the position of the signals D and S is
disturbed.
When the wheels of the train strike the reversing track instrument b
the circuit is closed through wires 11, 13, and 19, helix of electro-mag-
net K², wire 20, hclix of electro-magnet K**, wire 21, track instrument b,
and wires 22, 12, back to the battery, the electro-magnets K and R**
are vitalized, the locking levers f³, f** are caused to release their signals,
and the signals 1, he, in the houses D and S return to their original
positions, the former moving out of sight, and the latter into sight.
From this description it will be readily seen that no collision can take:
place. If a train should remain stationary on the track between the
signals S¹ and D' the signal D will show danger, and a succeeding train.
can be stopped easily before any accident arises, since the first train will
not take off the danger signal D until it. passes the track instrument b..
But if from any cause the signals should fail to operate when the train
passes the track instrument a, the safety signal S, instead of being
moved out of sight, will remain in sight, its danger is indicated, and
the engineer by stopping his train can readily ascertain the defect.
:
On a double track railway the signal houses and track instruments.
will be arranged on opposite sides of the track, as shewn in Figure 1,
and the connections are made as shewn in Figure 2. The operations of
the signals remains the same as above described.
By constructing the track instrument with a piston Jo, and an air
cylinder K°, as above described, the time when the circuit through said
track instrument closes becomes dependent upon. the time required by
the piston Jo to fall back to its original position. By connecting a track
instrument directly with audible or visible signals at or near a station,
the station master is enabled to ascertain when a train approaches, since,
. whenever a train passes the track instrument, applied for this purpose at
a suitable distance from the station, the signals will be displayed or kept
ringing for a sufficient length of time to secure the attention of the
station master or of his assistants..
From this description it will be seen that a single battery serves to
operate all the signals, whereby the cost of the apparatus, and the

page_text: by the combination of the safety signals with the danger signals, the
system is rendered safe under all circumstances.
By the use of gravitation the danger signals are made to shew safety,
and the safety signals to show danger. By the use of electro-magnetism
the danger signal is made to shew danger, and the safety signal to show
safety. If, therefore, from any cause the battery used should become
inoperative, gravitation would cause the safety signals to continue signals
of danger, and the safety of trains is insured. If, however, by the
breaking of any of the wires the clectro-magnetism should, act only to
display the signal of danger without taking it off, the worst possible
result would be a slight delay, but all head and rear collisions are
efféctually. prevented.".
By reason of the absolute safety of a railway supplied with this system
of signals the trains can be run more rapidly and in quicker succession
than they can on lines without such signals, and the business of the
line can be considerably increased.
.
Having thus fully described the said Invention, as communicated to
me by my foreign correspondents, and the manner of performing the
same, I wish it understood that I claim,—
•
First. The combination of a scries of signal houses arranged in pairs
alongside a railway track, with line wires extending from one and the
same battery along the line of the railway and connecting with electro-
magnets in the signal houses, and with track instruments situated near
the rails, in the manner herein described.
▸
Second. The combination of signals of safety S with signals of danger
D, the said signals being actuated alternately by electro-magnetism and
by gravitation, as herein set forth and for the purpose specified.
Third. The combination of locking levers f³, f, with the signals D
and S, in the manner herein set forth and for the purpose described.
Fourth. The combination of a piston J° and cylinder K° with the key
lever L° of a circuit-closing instrument, as herein described.
Fifth. The air cushion formed in the top of the cylinder, K° by means
of the piston J" and passage 0°, as herein set forth.
Sixth. The air passages 0°, Q°, and P°, communicating with the
interior of the cylinder K° above and below the piston Jo, in combination
with this piston and with the key lover L°, as herein described.

page_text: Seventh. The adjustable valve R° which controls the return of the
air from the part of the cylinder below the piston to the part above the
piston, as herein set forth.
Eighth. The combination with the outer end of the track lever B° of a
spring E° whereon the said track lever rests, as herein described.
Ninth. The packing device H° so arranged upon the track lever as to
close the opening G° of the chamber F° as herein set forth.
In witness whereof, I, the said George Haseltine, have hereunto set
my hand and seal, this Tenth day of October, in the year of
our Lord One thousand eight hundred and seventy-three.
Witness,
HY. J. NOONE,
8, Southampton Buildings,
London.
GEORGE HASELTINE. (L.S.)