IMPROVEMENTS IN RAILWAY SIGNAL APPARATUS
Year: 1880

page_text: LETTERS PATENT to William Robert Sykes, of Nunhead, in the County of
Surrey, Telegraph Engineer, for an Invention of "IMPROVEMENTS IN RAILWAY
SIGNAL APPARATUS."
PROVISIONAL SPECIFICATION left by the said William Robert Sykes at
the Office of the Commissioners of Patents on the 10th May 1880.
WILLIAM ROBERT SYKES, of Nunhead, in the County of Surrey, Telegraph
Engineer. "IMPROVEMENTS IN RAILWAY SIGNAL APPARATUS."
My Invention consists of improvements in railway signal apparatus, and has
reference more particularly to improved mechanical and electrical arrangements for
carrying out the combined lock and block system of signalling or working signals
described in the Specification of former Letters Patent granted to me, and dated
the 23rd February 1875; No. 662.
31
In the said Specification in explaining the operation or working of the system at
three given stations or signalling points, which I called A, B, and C, I described that
the lock at A was released by the back motion of the starting lever at B, and I
afterwards remarked that this might be done by the forward motion of the lever
at B. In practice I find the latter is generally to be preferred; and in carrying it
out I now give the signal "clear on an indicator at A by motion from a plunger
at B, which plunger takes the place of the spring and collar described in my former
Specification. When the plunger has been acted upon to give the signal "clear" at
A, as just mentioned, it cannot be acted upon again until the starting lever at B,
which has been locked in its normal position, has been released by C. The starting
lever at B when in its other position, that is, when pulled over and the signal is
down, is locked, and it may be released either by a treadle in advance of the signal,
as hereinafter described, or by a plunger, which will call the platform plunger,
under the control of the station staff at B (an arrangement which will be found
particularly advantageous in foggy weather, when the train cannot be seen by the
signalman); thus the signal man at B cannot give "clear" to A until B has given
the train onto C, and C has released B's starting lever, which B must pull over and
again put back again after it has been released by the treadle or the platform
plunger, as above described. The back motion of B's starting lever brings two

page_text: springs into contact, which then send a reverse current to the arm galvanometer
at A, thus indicating to the signalman at A that the section of the line between A
and B is clear (but not unlocking the lever at A), and that he can ask the
signalman at B to accept another train, which the latter can do by any suitable
No other block
means, such as a bell worked electrically or a telephone.
instruments are required, because in my arrangements, not only is the arm
galvanometer a block instrument in itself, but also the indicator is both a block
and locking instrument.
It will readily be understood that at junctions, where one line feeds several, that
the plunger by means of which the train on that one line is accepted must be tied
to the other levers, so that the movement of any one of them (forward or back)
will have the effect of freeing the plunger, so that it can be again acted upon. All
the levers feeding the other lines would be locked by the signal boxes in advance.
Sometimes I connect the point levers and tie them with the plunger gear, so that
the movement of the points in shunting indicates to the boxes around "line
blocked," and prevents the signalman from accepting a train from the road that
corresponds with the points he is shunting on. Sometimes also I arrange for the
station master to lock the signal lever for letting trains into a siding or sidings;
when he unlocks this lever the signalman, by pulling it over and letting the train
in, and then putting the lever back again, would by the backward movement
release the stop signals of the lines which feed the junction (the siding signal lever
being tied with the starting lever), so that he would be enabled to take another
train from either direction after he has put the points back.
I will now proceed to describe more in detail the arrangement and working of
the apparatus at station B.
1
The signalman has in front of him and over the lever a case which contains the
upper lock and has two oblong openings, behind which and within the case are pieces
of tin or other suitable material; the tin behind the upper opening is painted on the
upper half "
clear," and on the lower half "locked;" the tin behind the lower
opening is painted on the upper half "train on," and on the lower half "train
passed" or "clear." (The words on the tins may of course be varied if required.)
The pieces of tin are attached to blades that pass through the bottom of the case,
and are jointed to rods which are attached to the lower gear. The blade to which
is attached the upper tin with the words "locked" and "clear" is held up by an
angle piece (mounted on a stud and bracket), which angle piece rests under a pin.
Part of the angle piece is an armature held up by the poles of an electro-magnet
which is attached to permanent magnets. The electro magnet communicates by a
wire through the arm galvanometer with a spring in a case at the station in
advance, which spring is put in communication with a battery by means of a
plunger and angle piece. The blade which carries the upper tin piece is jointed to
a rod which is attached to a cross bar lifting a sliding piece (which forms a lock)
out of and into a notch cut in a tappet. This tappet is attached to the signal lever
by means of a stud. Attached to the said cross bar is a roller which is lifted by a
cam carried by a bracket. Mounted on the said cam is a T shaped arm connected
by a rod to a pin plate bolted to the signal lever. To a stud in the cam is attached
a rod which works a blade forming a continuation of, but being a distinct pieco
from, the blade which carries the lower tin piece. This blade which carries the
lower tin piece with the words "train on " and "clear," is held up by a click
which rests on a pin in the said continuation blade. The click is pushed off the
pin in this blade by means of the plunger and angle piece, and this causes the
blade carrying the lower tin piece to drop. This blade is put up by the signal
lever being pulled over, and as this lowers the continuation blade by means of the
rod which works it, the pin is allowed to get underneath the click, so that the
backward motion of the signal lever then raises both the blade carrying the
lower tin piece and the continuation blade.
When the signal lever is put back two springs are pressed together by the blade
which carries the lower tin piece, and a contact being thus made electric communi.

page_text: cation is carried to the arm galvanometer at station A in the rear, which pulls the
arm at that station to the "clear" position, and being a current from a different
battery reverse to that sent by the plunger spring, it does not repel, but attracts
the armature of the electro magnet, and therefore does not unlock the signal lever.
I will now describe the arrangement of the treadle hereinbefore referred to by
means of which the starting lever is released. By this arrangement the passing of
the last carriage of a train sends a current to the electro magnets and causes them
to repel the armature, thereby dropping the blade which carries the upper tin piece
and taking out the back lock, so that the starting lever can be put back, and
the "clear" signal be given to the station in the rear, the lever being itself
simultaneously locked.
The treadle is of sufficient length, say 20 feet, to take at the same time both
wheels on one side of the carriage. The tire of the wheels comes between the rail
and the treadle, forces the treadle away from the rail, and thereby gives motion to
an arm which pulls a rod connected to a crank. This crank pulls down another
rod so that a tappet thereon passes over a click. When the last wheel has passed
the treadle, the treadle under the action of a weight falls back to the rail, and the
mechanism is thus returned to its normal position. The click in its ascent makes
a contact with a spring which is in communication by wire with the electro magnet.
The current which is thus transmitted repels the armature of this magnet and
releases the starting lever, as above described.
For working single lines the plunger may be used either in conjunction with or
separately from the treadle.
In order to prevent the contact being made by a trolley passing along the line,
I prefer to make the treadle in two distinct lengths at a distance apart, say 6 feet,
which is greater than the distance between the wheels of the trolley. The two
portions of the treadle are connected by a cross bar, and unless they are both acted
upon together, as they would be by a passing train, the mechanism is not sufficiently
moved to actuate the tappet and click. This arrangement of double treadle may
be applied to other railway signal apparatus, in which a treadle acted upon by
the passing train is used, such for example, as the apparatus described in the
Specification of Cheeswright's Letters Patent dated 14th December 1870, No. 4841.
Instead of releasing the starting lever by means of a treadle, it may be released
by means of the platform plunger already herein referred to. This plunger is in
connection with a local battery from which a wire is led to the electro-magnets in
the case; this wire has a break where two springs are interposed, and when the
lever is pulled over these springs are brought together and the electric circuit
thereby made complete; the lever cannot be put back until one of the station staff
works the platform plunger, so as to release the lock in the same manner as is done
by means of the treadle. As soon as the lever has been put back the springs
separate, the electric circuit is broken, and the plunger therefore cannot take effect
again until the lever has again been pulled over. The platform plunger may be
worked in connection with either the distant lever or the starting lever.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Robert Sykes in the Great Seal Patent Office on the 10th
November 1880.
WILLIAM ROBERT SYKES, of Nunhead, in the County of Surrey, Telegraph
Engineer. "IMPROVEMENTS IN RAILWAY SIGNAL APPARATUS."
My Invention consists of improvements in railway signal apparatus, and has
reference more particularly to improved mechanical and electrical arrangements for
carrying out the combined lock and block system of signalling or working signals,
described in the Specification of former Letters Patent granted to me, and dated the
23rd February 1875, No. 662.
In the said Specification in explaining the operation or working of the system at
3 given stations or signalling points, which I called A, B, and C, I described that
the lock at A was released by the back motion of the starting lever at B, and
I afterwards remarked that this might be done by the forward motion of the lever
at B. In practice I find that the latter is generally to be preferred, and in carrying
it out I now give the signal "clear" on an indicator at A by motion from a
plunger at B, which plunger takes the place of the spring and collar described in
my former Specification. When the plunger has been acted upon to give the
signal "clear at A, as just mentioned, it cannot be acted upon again until the
starting lever at B which has been locked in its normal position has been released
by C. The starting lever at B when in its other position, that is, when pulled over
and the signal is down, is locked, and it may be released either by a treadle in
advance of the signal, as hereinafter described, or by a plunger which I will call
the platform plunger under the control of the station staff at B (an arrangement
which will be found particularly advantageous in foggy weather when the train
cannot be seen by the signal man); also, when the starting lever at B is pulled
over and the signal is down, the plunger which releases A is locked until the train
has passed over the treadle in advance of the starting signal or until the platform
plunger has been used. Thus the signalman at B cannot give "clear" to A until B
has given the train on to C, and C has released B's starting lever, which B must.
pull over and again put back after it has been released by the treadle or platform
plunger, as above described. The back motion of B's starting lever, brings two
springs into contact, which then send a reverse current to the arm galvanometor
at A, thus indicating to the signalman at A that the section of the line between
A and B is "clear" (but not unlocking the lever at A), and that he can ask the
signalman at B to accept another train, which the latter can do by any suitable
means, such as a bell worked electrically or a telephone. No other block instru-
ments are required, because in my arrangements not only is the arm galvanometer
a block instrument in itself, but also the indicator is both a block and locking
instrument.
It will readily be understood that at junctions, where one line feeds several, that
the plunger by means of which the train on that one line is accepted must be tied
to the other levers, so that the movement of any one of them (forward or back) will
have the effect of freeing the plunger so that it can be again acted upon. All the
levers feeding the other lines would be locked by the signal boxes in advance.
Sometimes I connect the point levers and tie them with the plunger gear so that
the movement of the points in shunting indicates to the boxes around "line
blocked," and prevents the signalman from accepting a train from the road that
corresponds with the points he is shunting on. Sometimes also I connect the
plunger to the point levers in such a manner that when the signalman has plunged
to receive a train the plunger locks all the points leading to the line he has
plunged to receive a train on, so that they cannot be moved until the train has

page_text: arrived at the station and the stop signal has been put to "danger." I also arrange
so that when a lever working a point which leads to the main line is pulled over,
that lever locks the plunger so that it cannot be used to receive a train on the line
that is fouled by the points until the points have been replaced in their normal
position.
Sometimes also I arrange for the station master to lock the signal lever for
letting trains into a siding or sidings; when he unlocks this lever the signalman
by pulling it over and letting the train in, and then putting the lever back again,
would, by the backward movement, release the stop signals of the lines which feed
the junction (the siding signal lever being tied with the starting lever), so that he
would be enabled to take another train from either direction after he has put the
points back.
I will now proceed to describe more in detail the arrangement and working of
the apparatus at station B.
"
The signalman has in front of him, and over the lever, a case which contains the
upper lock. This case with the mechanism contained therein is represented in two
side elevations in Figures 1 and 3, and in front elevation in Figure 2 of the
annexed Drawings, the case itself being partly in section in each of these Figures
in order to allow the internal parts to be seen. The case is also seen at a in Figure 4,
which is a side elevation on a smaller scale of the starting lever and the parts
more immediately connected therewith. The case has two oblong openings b and c
(Figure 2), behind which and within the case are pieces d and e (Figures 1 and 3)
of tin or other suitable material; the tin 'd behind the upper opening b is painted
on the upper half "clear" and on the lower half "blocked;" the tin e behind the
the lower opening c is painted on the upper half "train on," and on the lower half
train passed" or "clear." (The words on the tins may, of course, be varied if
required.) The pieces of tin are attached to blades marked respectively A and U
which pass through the bottom of the case and are jointed to rods which are
attached to the lower gear. The blade A, to which is attached the upper tin d
with the words "blocked" and "clear," is held up by an angle piece C (mounted
on a stud C and bracket C'), which angle piece rests under a pin B. Part of the
angle piece is an armature D held up by the poles of an electro magnet E which is
attached to permanent magnets E¹. The electro magnet communicates by a wire
through the arm galvanometer with a spring (similar to that shewn at F, Figures 2
and 3) in a case at the station (C) in advance, which spring is put in
communication with a battery by means of a plunger and angle piece at
station (C), similar to those represented respectively at G and H, in Figure 1.
The blade A is jointed at A¹ (Figure 4) to a rod I which is attached to a crossbar J
(seen on a larger scale in the detail view, Figure 5) lifting a sliding piece K (which
forms a lock) out of and into a notch f cut in a tappet L. This tappet is attached
to the signal lever M (Figure 4) by means of a stud N. Attached to the said
cross bar J is a roller O which is lifted by a cam P carried by a bracket Q. This
bracket is bolted to the bar R, Figures 4 and 5. Mounted on the said cam P is
aT shaped arm P¹ connected by a rod P2 (Figure 4) to a pin plate P³ bolted to
the signal lever M. To a stud R' in the cam P is attached a rod S which works a
blade T (Figure 2) forming a continuation of, but being a distinct piece from, the
blade U (Figure 1). This blade U, which carries the lower tin piece e with the words
"train on " and "clear," is held up by a click V (Figure 2) which rests on a pin W
in the blade T. The click V is pushed off the pin in this blade T by means of the
plunger G and angle piece H, and this causes the blade U carrying the lower tin
piece to drop. This blade U is put up by the signal lever M (Figure 4) being
pulled over, and as this lowers the blade T by means of the rod S (Figures 4 and 5)
which works it, the pin W is allowed to get underneath the click V, so that the
backward motion of the signal lever then raises both the blades T and U.
When the signal lever is put back two springs X (Figure 2) mounted on a
bracket Y are pressed together by the blade U and a contact being thus made
electric communication is carried to the arm galvanometer at station "A" in the rear,

page_text: which pulls the arm at that station to the "clear" position, and being a current from
a different battery reverse to that sent by the plunger spring F (Figure 2), it does
not repel, but attracts, the armature of the electro magnet E in the case at
station "A," and therefore does not unlock the signal lever.
I will now describe the arrangement of the treadle herein before referred to by
means of which the starting lever is released. By this arrangement, which is
represented in Figure 6, the passing of the last carriage of a train sends a current
to the electro magnets (E, Figure 1), and causes them to repel the armature
(D, Figure 1), thereby dropping the blade A which carries the upper tin piece, and
taking out the back lock so that the starting lever can be put back, and the "clear"
signal be given to the station in the rear, the lever being itself simultaneously
locked.
The treadle A, Figure 6, is of sufficient length, say 20 feet, to take at the same
time both wheels on one side of a carriage. The tire of the wheels comes between
the rail B and the treadle, forces the treadle away from the rail, and thereby gives
motion to an arm C, which pushes a rod D connected to a crank E. This crank,
through the intermediation of a cross bar E', pulls down another rod F (which
slides in brackets G, G), so that a tappet F¹ thereon passes over a click H.
When the last wheel has passed the trendle, the treadle under the action of a
weight E falls back to the rail, and the mechanism is thus returned to its
normal position. The tappet F¹ in its ascent pushes the click H into contact
with a spring J, which is in communication by wire with the electro magnet
(E, Figure 1). The current which is thus transmitted repels the armature of this
magnet and releases the starting lever as above described.
For working single lines the plunger may be used either in conjunction with or
separately from the treadlo.
In order to prevent the contact being made by a trolley passing along the line I
prefer to make the treadle A in two distinct lengths (as represented in Figure 7) at
a distance apart, say 6 feet, which is greater than the distance between the wheels
of the trolley. The two portions A, A, of the treadle are connected by a cross bar K,.
and unless they are both acted upon together, as they would be by a passing train,
the mechanism is not sufficiently moved to actuate the tappet and click. This
arrangement of double treadle may be applied to other railway signal apparatus in
which a treadle acted upon by the passing train is used, such for example as the
apparatus described in the Specification of Cheeswright's Letters Patent, dated
14th December 1876, No. 4841.
Instead of releasing the starting lever by means of a treadle it may be released
by means of the platform plunger, already herein referred to. This mode of
releasing the lever will be understood on reference to Figure 8. g is the platforin
plunger; it is in connection with a local battery / from which a wire i is
led to the electro magnets in the case a; this wire has a break at where two
springs are interposed, and when the lever is pulled over these springs are brought
together and the electric circuit thereby made complete; the lever cannot be put
back until one of the station staff works the platform plunger g, so as to release
the lock in the same manner as is done by means of the treadle. As soon as the
lever has been put back the springs above mentioned separate, the electric circuit
is broken, and the plunger g therefore cannot take effect again until the lover has
been again pulled over. The platform plunger may be worked in connection with
either the distant lever or the starting lever.
And having now described the nature of my said Invention, and in what manner
the same is to be performed, I declare that I claim,-
First. Arranging combined lock and block railway signal apparatus in such
manner that the signalman at a given station, say, "B," cannot signal "clear" to the
station "A" in the rear until he has given the train on to the station "C" in
in advance, and the signalman at "C" has released the starting or distant lever at
"B," which lever the signalman at "B" before he can signal "clear" to "A" must
pull over and again put back after it has been released by a treadlo or otherwise,

page_text: all substantially as hereinbefore described with reference to the annexed Drawings.
Second. The combination or arrangement of parts of railway signal apparatus,
substantially as herein before described and represented in Figures 1 to 5 of the
annexed Drawings.
Third. The arrangement of treadle and parts connected therewith for releasing
the starting or distant lever, substantially as hereinbefore described and represented
in Figure 6 of the annexed Drawings.
Fourth. The double or divided treadle arranged and working substantially as
as herein before described and represented in Figure 7 of the annexed Drawings, for
the purpose explained.
Fifth. The fitting and employment in connection with railway signal apparatus
of what I have herein termed a "platform plunger," substantially as hereinbefore
described and represented in Figure 8 of the annexed Drawings, for the purpose
explained.
In witness whereof, I, the said William Robert Sykes, have hereunto set my
hand and seal, this Fourth day of November, One thousand eight hundred
and eighty.
WILL. ROBT. SYKES. (L.S.)