Improvements in and in connection with Electrical Railway Signals.
Year: 1893

page_text: . Date of Application, 11th July, 1893
Complete Specification Left, 11th Apr., 1894-Accepted, 12th May, 1894
PROVISIONAL SPECIFICATION.
Improvements in and in connection with Electrical Railway
Signals.
I, FRANK BOULTON ASPINALL, of No. 13 Blessington Road, Lee, in the
County of Kent, Electrical Engineer, do hereby declare the nature of this invention
to be as follows:-
This invention relates to improvements in electric railway signals. The
signals are so arranged that the action is automatic; the train passing a signal
station leaves the signals behind it blocked and they so remain until the train
passes the next signal station; the previous block is then removed and the signals
last reached are blocked in their turn. A train reaching a blocked section of the
line is warned by an audible signal and if the warning be neglected the steam is
presently shut off automatically and the brakes are applied.
I provide by the side of the line of rail insulated bars so that instruments on the
engine of a passing train may come into contact with these bars in succession.
Of these insulated bars the first which the train meets as it approaches a signal
station is equivalent to a distance signal post; the train in passing it receives a
notification of the state of the line section in advance of the train, whether it be
clear or blocked.
The next insulated bar which the train meets is equivalent to a home signal post,
it gives to the passing train the same notification as is received on passing the first
bar and it also by an automatic action if need be causes the steam to be shut off
from the engine and the brakes to be applied. If desired these two bars may be
continuous or nearly so. As the train passes the third insulated bar, the signals
immediately behind it are blocked and as it passes the fourth bar the block is
removed from the preceding station. The third and the fourth bars may be
substituted by switches moved by the passing train. I will describe how the
several results above mentioned are brought about; a suitable instrument projects
from the engine and when this instrument is in contact with the first insulated
bar a gap in a battery circuit is thereby closed and if the circuit be otherwise
complete, as it is when the line is clear, a current flows through the coils of an
electro-magnet upon the engine. Now the engine also carries a galvanic battery
which supplies two circuits which being upon the engine I call "local circuits" in
one of these is a bell or "buzzer" the constant sound of which is a safety signal.
The other local circuit controls a mechanism which so long as the current continues
to flow is inoperative but when it ceases this mechanism (which may be worked by
steam) becomes operative and automatically it shuts off the steam from the engine
and it applies the brake. By a movement resulting mechanically from the insulated
bar being struck by an instrument on the engine a gap in the bell or "buzzer
circuit is opened, but this gap is bridged by an electric switch under the control of
the electro magnet previously mentioned which maguet receives current from the
insulated bar provided the line be clear. But if the line be not clear the opening
of the bell or "buzzer" circuit is complete and a danger signal is given. On
receiving this the engine driver should stop the train; but assuming the distance
signal to be neglected; on passing the second insulated bar another movement
mechanically produced opens a gap in both the local battery circuits and (the line
being blocked) the gaps are not closed by the switch, consequently the control
mechanism is set to work, the steam is shut off and the brakes are applied. If on
the other hand the line be clear the electro-magnet will have moved the switch,
the local battery circuits will remain closed and safety will continue to be indicated.
"

page_text: As the engine passes the third insulated bar or the switch which replaces this bar a
battery circuit is thereby closed through the coils of an electro magnet conveniently
placed by the wayside and the attraction of the magnet moves a switch in such
manner as to open a gap in the battery circuit of the first and the second insulated
bars and these bars are thereby brought into a condition to indicate to a following
train that the line is blocked. This may be indicated also by an index or pointer
with which the electric switch may be provided. The movement of the electric
switch caused by contact with the third bar closes a gap in a battery circuit in
which the fourth bar is included and this circuit leads back to the preceding road
side switch where it includes an electro-magnet-when the train passes the fourth
insulated bar this magnet is excited and it closes the switch, causing it to apply
the battery to the preceding bars the equivalents for the distance and the home
signals. Hence immediately one pair of signals has been blocked the pair in rear
are placed to line clear and the latter operation can only be performed when the
former has been efficiently accomplished.
It will be observed that the block or danger signal is always given by the
absence of battery current whilst the passage of a current gives a safety indication.
It will also be observed that when a train is stopped at the insulated bar
corresponding to a home signal the driver cannot start again until the signal is
taken off; that is to say until an electric current is supplied to the bar through the
line wire.
This main system of signals adapts itself well to the application of other
secondary systems such as are necessary at siding points and elsewhere for all that
is required to ensure the danger indication is the automatic opening of a gap in the
circuit wire through which the safety or line clear indication is automatically
passed.
By suitable modifications of above arrangement at all sidings, junctions and
crossings only one train can be on a section at one time all other roads being
blocked the switching is done by switchmen but the blocking of the roads is
automatic.
Dated this 11th day of July 1803
COMPLETE SPECIFICATION.
Improvements in and in connection with 'Electrical Railway
Signals.
I, FRANK BOULTON ASPINALL, of No. 13 Blessington Road, Lee, in the
County of Kent, Electrical Engineer, do hereby declare the nature of this inven-
tion 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 improvements in electrical railway signals. The signals
are so arranged that the action is automatic, the train passing a signal station
leaves the signals behind it blocked and they so remain until the train passes the
next signal station; the previous block is then removed and the signals last reached
are blocked in their turn. A train reaching a blocked section of the line is warned
by an audible signal and if the warning be neglected the steam is presently shut
off automatically and the brakes are applied.
I provide by the side of the line of rail insulated bars so that instruments on the
engine of a passing train may come into contact with these bars in succession.
Of these insulated bars the first which the train meets as it approaches a signal
station is equivalent to a distance signal post; the train in passing it receives a
notification of the state of the line section in advance of the train whether it be
clear or blocked.
:
The next insulated bar which the train meets is equivalent to a home signal post
it gives to the passing train the same notification as is received on passing the first

page_text: "
bar and it also by an automatic action if need be causes the steam to be shut off
from the engine and the brakes to be applied. Preferably the second bar is
divided into two the first part cutting off the steam and the second putting on the
brakes. If desired the first and second bars may be continuous or nearly so.
As
the train passes the third insulated bar the signals immediately behind it are
blocked and as it passes the fourth bar the block is removed from the preceding
station. The third and the fourth bars may be substituted by switches moved by
the passing train. I will describe how the several results above mentioned are
brought about; a suitable instrument projects from the engine and when this
instrument is in contact with the first insulated bar a gap in a battery circuit is
thereby closed and if the circuit be otherwise complete, as it is when the line is
clear, a current flows through the coils of an electro-magnet upon the engine. Now
the engine also carries a galvanic battery which supplies two circuits which being
upon the engine I call "local circuits in one of these. is a bell or " buzzer the
constant sound of which is a safety signal. The other local circuit controls a
mechanism which so long as the current continues to flow is inoperative but when
it ceases this mechanism (which may be worked by steam) becomes operative and
automatically it shuts off the steam from the engine and it applies the brake. By
a movement resulting mechanically from the insulated or another bar being struck
by an instrument on the engine a gap in the bell or "buzzer " circuit is opened, but
this gap is bridged by an electric switch under the control of the electro magnet
previously mentioned which magnet receives current from the insulated bar
provided the line be clear. But if the line be not clear the opening of the bell or
"buzzer" circuit is complete and a danger signal is given. Preferably however
the arrangement is reversed a signal only being given when the line is blocked.
On receiving this the engine driver should stop the train; but assuming the
distance signal to be neglected, on passing the second insulated bar another move-
ment mechanically produced opens or closes a gap in the local battery circuits and
(the line being blocked) the gap is not closed or opened by the switch, consequently
the control mechanism is set to work, the steam is shut off and the brakes are
applied. If on the other hand the line be clear the electro-magnet will have
moved the switch, the local battery circuit will remain closed or open and safety
will continue to be indicated. As the engine passes the third insulated bar or the
switch which replaces this bar a battery circuit is thereby closed through the coils
of an electro magnet conveniently placed by the way side and the attraction of the
magnet moves a switch in such manner as to open a gap in the battery circuit of
the first and the second insulated bars and these bars are thereby brought into a
condition to indicate to a following train that the line is blocked. This may be
indicated also by an index or pointer with which the electric switch may be
provided. The movement of the electric switch caused by contact with the third
bar closes a gap in a battery circuit in which the fourth bar is included and this
circuit leads back to the preceding road side switch where it includes an electro-
magnet-when the train passes the fourth insulated bar this magnet is excited and
it closes the switch, causing it to apply the battery to the preceding bars the
equivalents for the distance and the home signals. Hence immediately one pair of
signals has been blocked the pair in rear are placed to line clear and the
latter operation can only be performed when the former has been efficiently
accomplished.
It will be observed that the block or danger signal is always given by the
absence of battery current whilst the passage of a current gives a safety
indication.
It will also be observed that when a train is stopped at the insulated bar corre-
sponding to a home signal the driver cannot start again until the signal is taken
off; that is to say until an electric current is supplied to the bar through the line.
wire.
This main system of signals adapts itself well to the application of other
secondary systems such as are necessary at siding points and elsewhere for all that

page_text: is required to ensure the danger indication is the automatic opening of a gap in the
circuit wire through which the safety or line clear indication is automatically passed.
By suitable modifications of above arrangement at all sidings, junctions and
crossings only one train can be on a section at one time all other roads being
blocked; the switching is done by switchmen but the blocking of the roads is
automatic.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a diagrammatic view showing the circuits used in connection with a
station or section of the line without sidings,
Figure 2 is a diagrammatic view showing the circuits on the engine and
Figures 3 and 4 are an elevation and plan of the mechanism on the engine.
Figures 5 and 6 are similar views to Figures 3 and 4 but show the parts in
different positions.
Figure 7 shows the application of the invention to a pair of lines connected by
cross-over points.
The train is assumed to be passing the station and travelling in the direction of
the arrow (Figure 1) the line behind it being blocked-A, B, C, D and E are five
insulated contact plates at the side of the line B and C being the parts of the
above described second bar but A B and C are all connected together by the wire a
or they may be replaced by a single long plate-A', B and C are three plates
standing up from the ground at different elevations. Preferably the plates A B C
A B C are of considerable length.
When the train reaches A A¹ a rod F operating the lever F' (Figure 2) pivotted
at F2 on the engine is mechanically raised by reason of a part not shown striking
against A' and the lever F¹ is thereby raised a certain distance so connecting the
contact plates G G' and completing a circuit from the battery H through the
wire spring contact maker J contact J' wire c, contact G, lever F¹, contact G¹,
wire d, bell K and wires e and back to the battery. If therefore the spring J
is in the position shown in Figure 2 as is the case if the line is blocked the bell is
rung giving a danger signal. If however the line is clear the electromagnet L is
at this time (as is hereinafter described) attracting its armature J³ on the spring J
and the latter is in contact with J2 and not with and the bell circuit being thus
The wire
broken no signal is given. This is effected in the following manner.
forming the coils of the electro magnet L terminates at one end in a brush M and
at the other in an earth connection through the frame of the engine or otherwise.
If the line has been cleared a current has been passed as is hereinafter described
in the coils of the maguet N (Figure 1) which has therefore attracted its
armature on the balanced lever O pivotted at 02. This lever is shown in end
elevation at Figure 1*. It is made of non-conducting material and carries at
its ends bent conductors 0 05 whose points are normally above the mercury
cups h¹ h² n² n² respectively. These cups are connected to the wires g h m (of
the preceding station) and n respectively. When the magnet N attracts its
armature the conductor 0 connects the cups and therefore when the
brush M (Figure 2) passes over the insulated plate A a circuit is completed from
the battery P through the wire g cup h¹ conductor 04 cup 2 wire hand then by
earth to the magnet L and brush M on the engine and by the plate A and wire a
back to the battery P. On the other hand if the line is blocked the conductor O
does not dip into the cups and the circuit being thus broken no current
passes through the coils of the magnet L and the bell on the engine rings as above
described.
Exactly the same thing takes place when the engine reaches B B' except that
here the rod F is raised higher than at A A¹ so that it not only causes the
lever to connect G G but it also depresses its tail end F³ (Figures 3 to 6)
sufficiently far to free the pin R' on the arm R2 fixed to the wheel R and pulled
by the spring R³. Unless therefore the wheel is otherwise retained (as is the case
when the line is clear) the wheel is turned by the spring thereby operating a

page_text: .f
valve and connecting a steam pipe S' to the pipe S2 and admitting steam to the
cylinder S so operating the lever S3 which shuts off the steam from the engine.
It will be observed however that when the line is clear and the magnet L.
attracts its armature and brings J and J into contact a circuit is completed from
the battery H through the wire b, spring J, contact J2, wire j, electro inagnet T
and wire back to the battery H so that the magnet T is caused to attract its
armature T thus pulling downwards the rod T2 pivotted to the armature, this rod
is shaped like an inverted U and its other branch when it is pulled down as above.
described. comes into the path of the pin R on the wheel R (Figures 3 to 6) and
the wheel cannot turn however much the tail end F³ of the lever F is depressed, the-
C' does not act on the rod F
steam therefore is only cut off if the line is blocked.
but upon another rod operating another set of apparatus similar to that shown in
Figures 3 to 6 whereby the breaks are put on if C is passed when the line is.
blocked.
When the engine reaches D a circuit is completed from the battery U through.
the wire k, magnet N¹, earth at k¹, earth connection, magnet L and brush M on
engine to the plate D and through the wire back to the battery U. This causes
the magnet N¹ to attract its armature O³ so lifting the conductor O' out of the-
cups blocking the line as above described, it also causes the conductor O³ to.
dip into the mercury cups n' n² so that when the engine reaches E a circuit is.
completed from the battery V through the wire n, cup 2 conductor 0 cup n
wire m to the magnet N of the preceding section to earth at m' of the preceding
section and so through the earth contact, magnet L and brush M on the engine to
the plate E and by the wire o back to the battery V. Thus the magnet N of the:
preceding section is caused to attract its armature clearing the line in this section.
in the manner above described.
In order further to illustrate my invention I show at Figure 7 the general'
arrangement in the case where a train has to be shunted from one line to the
other (where there is no siding) to allow another train to pass, as in the case.
of a slow goods train having to make way for an express passenger train.
Both the up and the down line are provided with a set of apparatus similar
to that shown at Figure 1.
A slow goods train approaches the signals at (a), and the section marked (1).
being clear, the signals are in its favour, it therefore proceeds past the signals
blocking them behind it. In the ordinary way if the train had to proceed on..
the same line it would do so as in the case of a straight line; but in this case.
it is wanted to shunt the train on to section (2) to allow the express to pass.
The points at (3) are closed, and it is necessary for the signalman to open:
these points to shunt the train. These points under ordinary conditions are
locked by suitable electrically controlled locking apparatus at (y) the points of
the two lines being electrically interlocked, so that if one pair belonging to
section (1) are locked, those of section (2) are locked, and if unlocked, both, are-
unlocked.
It will be noticed that, if a train is required to be shunted from section (1)
to (2), section (2) must be clear, section (1) being blocked by the presence of
train, thus the position of rocking switch at (6) will be "line blocked "and at E
❝ line clear."
Now the signalman pulls the switch at (n) over to position, down to up, and' if
the signals are in the proper position, the points are unlocked enabling him to pull
the points over. The action of opening the points blocks both the up and down
line, by opening circuit at (0) and () and all the time the points are open both.
lines are blocked.
The moment the points are open the train is now free to cross over, and in,
the action of crossing over, connects the insulated contacts (λ) and (μ) to earth,.
(A) putting the rocking switch at (8) at line clear, and (μ) putting the rocking
switch at () at line blocked, but both lines are still-blocked, owing to points.
being open.

page_text: ..
The locking apparatus at (y) has now locked the switches at the open position.
The signalman now puts the switch at (n) in the opposite position which enables
him to close his points and then section (1) is at line clear, and section (2) line
blocked, the shunted train being on section (2), and section (1) being clear for the
fast train to proceed.
As an extra safeguard I have an extra locking of the points at (p), which if a
train is passing over signals at a' or a² at the time the signalman wishes to open
his points he is unable to do so as the points are locked at (p), if a train is within
dangerous distance in this case it is preferable to make the insulated rail
continuous.
These can be interlocked if required.
In case of signals at either end of a bridge the wire carrying current to insulated
rails would be run over bridge, thus if the bridge was to break, as in the case of
the Tay bridge, these wires would be broken and both lines blocked.
In case of a train having to slow at a certain point or the engine driver having
to shut his steam off, and run, such as he failed to do in the Ffylde accident, by
putting an inclined plane at the side of the line the steam would be shut off at the
right time; in this case no electrical control would be required.
In the case of points controlling two lines running into one, only one rocking
switch is required as the position of the points, controls which line is clear, but in
this case if section run on to is blocked, both the lines running in are blocked and
if section is clear, only one section can be clear at a time.
By suitable arrangement of circuits, any number of roads can be controlled.
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. The combination of a normally broken or normally closed signal circuit on
the engine means which always tend to close or break such circuit at certain points
on the line and other means which tend to break or close the circuit at the same
point only when the line is clear.
2. The combination of a signal circuit on the engine normally broken or
normally closed at one point by one switch and normally closed or normally broken
at another point by another switch, mechanical means for always shifting one
switch at certain points on the line and electrical means for shifting the other
switch at the same point only when a circuit there is closed.
3. The combination on the engine of means always tending to cut off the steam
or apply the brakes as the case may be at certain points on the line and other
means which prevent such action only when the line is clear.
4. Producing the mechanical part of the action on the engine by means of a
fixed plate or rail.
5. Mechanism on the engine substantially as described and shown at Figure 2 of
the drawings.
6. Mechanism on the engine substantially as described and shown at Figures 3
to 6 of the drawings.
7. The combination of parts of a battery circuit on the line which can be
completed by the passage of the engine, a switch in the circuit and means for
closing the switch by an electric current from another point on the line.
8. The arrangement of electrical circuits substantially as described and shown at
Figure 1 of the drawings with or without the contacts B and C.
9. The arrangement of electrical circuits in connection with the points
substantially as described and shown at Figure 7 of the drawings.
Dated this 6th day of April 1894.
FRANK B. ASPINALL.