IMPROVEMENTS IN SIGNALLING ON RAILWAYS AND IN APPARATUS THEREFOR.
Year: 1874

page_text: LETTERS PATENT to Robert Currer, of Glasgow, in the County of
Lanark, North Britain, District Superintendant to the Caledonian
Railway Company, for the Invention of "IMPROVEMENTS IN SIGNALLING
ON RAILWAYS AND IN APPARATUS THEREFOR.
PROVISIONAL SPECIFICATION left by the said Robert Currer at the
Office of the Commissioners of Patents, with his Petition, on the
6th August 1874.
I, ROBERT CURRER, of Glasgow, in the County of Lanark, North
Britain, District Superintendant to the Caledonian Railway Company,
do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN SIGNALLING ON RAILWAYS AND IN APPARATUS THEREFOB," to be as
follows:-
This Invention has for its object to secure increased safety on railways
with simplicity and certainty in working signalling apparatus, and
comprises a modification of what is known as the "block system” of
working and signalling, together with special apparatus for the
signalling.

page_text: The improved apparatus as arranged for a single line is attached to
the ordinary electric transmission instrument, and fitted with two
buttons or keys marked respectively with the words “signal on
"and
"signal off," and on the former of these being depressed or pushed in it
causes the transmission from station B, for example, to the next 5
stations A and C on each side of signals showing that the sending
station B is blocked, and putting the small indicating semaphores at
those stations A, C, 66 on or at danger. When the other key is
depressed at one station B it puts the indicating semaphores at A and C
"off," showing the sending station B to be clear. In depressing the 1
"signal off" key however a detent is released, so that a spring provided
for the purpose moves a slide or cover over the end of the key, and the
signalman cannot in consequence depress this key a second time in
mistake or until he has moved back the covering slide by means of a
separate handle or button connected to it. The covering slide is also 1
connected to an indicating plate having marked on it the words “ on
and "off," and one or other of these words is shown at an opening
provided for the purpose, accordingly as the covering slide covers or
uncovers the "signal off” key.
"
In working the apparatus in ordinary cases the "signal off" key is
depressed when an approaching train is two sections distant, as notified
by wire on the train passing the next section the "signal on" key is
depressed, and on the train passing the station itself the covering slide is
moved back.
In adapting the improved apparatus for a double line the covering
slide is made to cover the "signal off" key when the "signal on" key
is depressed. The apparatus is repeated for both the up and down lines,
and in working with it the various outside semaphores will all be put to
"danger" as cach train passes through, and will be maintained in that
position during the entire interval until the next train is signalled as
approaching. This arrangement will render shunting and crossing
operations at any station much simpler and safer than when in working
the "block system" as commonly done, the semaphores are lowered
after a train as soon as it reaches the next block station.
The slide may be arranged to lock the key instead of covering it, or
to both cover and lock it.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Currer in the Great Scal Patent Office on
the 5th February 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
OURRER, of Glasgow, in tho County of Lanark, North Britain, District
Superintendent to the Caledonian Railway Company, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of August, in the year of
our Lord Ono thousand eight hundred and seventy-four, in the thirty-
eighth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Robert Currer, Her special licence
that I, the said Robert Currer, my executors, administrators, and assigns,
or such others as I, the said Robert Currer, my executors, adminis-
trators, and assigns, should at any time agree with, and no others, from
time to time and at all times thereafter during the term therein expressed,
should and lawfully might make, usc, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN SIGNALLING ON
RAILWAYS AND IN APPARATUS THEREFOR,' upon the condition (amongst
› others) that I, the said Robert Currer, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands
and scals, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said
Letters Patent.
"
NOW KNOW YE, that I, the said Robert Currer, do hereby declaro
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
the following statement in writing, reference being had to the accom-
panying Drawings, that is to say :-
My said Invention has for its object to secure increased safety on
railways with simplicity and certainity in working signalling apparatus,
and comprises a modification of what is known as the "block" system
of working and signalling, together with special apparatus for the
signalling.

page_text: And in order that my said Invention and the manner of performing
the same may be properly understood, I hereunto append a Sheet of
explanatory Drawings to be hercin-after referred to, and representing
my improved apparatus as combined with an arrangement of electric
signalling apparatus in common uso on railways. In these Drawings
the same referenco numerals are used to mark the same or like parts
wherever they are repeated.
Figure 1 of the Drawings is a front elevation of the clectric trans-
mission and receiving instrument, and Figure 2 is a view of the same
with the upper cover removed, and with the front board 1 of the lower
part turned back on its hinges to show my improved details which aro
fitted on this front board. In these Figures the parts are shown as
arranged for one of the two instruments used in working a double line.
The front 1 of the instrument is fitted with two buttons or piston
keys 2, 3, which the operator pushes inwards against the outward
pressure of springs when using them, and which may be marked
respectively with the words "signal on" or "on," and "signal off" or
"off," or be simply colored red and white, as shown, with the same
signification. Supposing the instrument that is being referred to to be
at station B of three successive signal stations A, B, C, the operator on
receiving an electric intimation that a train is starting from A depresses
the "signal on" key 2, which sets the indicating semaphore on the
instrument at A "on" or at danger, thus certifying the operator at A
that his intimation has been received, and remaining so until a succeeding
electric signal is transmitted from B until which the operator at A is not
to allow any succeeding train to pass. When the "signal on " key 2 is
depressed in this way it also causes a movement in the apparatus which
prevents the "signal off" key 3 from being depressed until after a
separato and special action has been applied to release it. This depression
of the "
signal off" key may be prevented by a slide or cover moving in
front of or over the key, as is herein-after explained more particularly
with reference to Figure 3, or it may be prevented as I now prefer by a
locking piece 4, which is moved into the way of the inside piece 5
attached to and moved by the key 3. This locking picco 4 is mounted
loosely on a stud and is formed with a plate or flange 6, having fixed in
it a pin entering into a slot in the end of one arm 7 of a three-armed
lever 7, 8, 9, centred on a stud and acted on by a spring 10. A two-
armed detent lever 11 centred on a stud and acted on by a spring 12

page_text: has a pin fixed in its lower end, which pin acting against a kind of
ratchet tooth formed on the flange 6 of the locking piece 4, prevents
that piece from being turned into the locking position by the action of
the spring 10 through the lever 7, 8, 9, but the upper end of the detent
5 lever 11 being formed with an inclined end piece 13, which is acted on
by the inside piece 14 of the upper or "signal on" key 2, the depression
of that key moves the detent lever 11 so as to release the locking piece 4,
and it instantly moves into the locking position in which it is represented
in Figuro 2. One arm 8 of the three-armed lever has on its end a
0 plate 15 on which are marked the words "on" and "off," and one or
other of these is shown at an opening 16 in the front 1. The third
arm 9 of the three-armed lever is in a position to be acted on by a
lateral key 17 which is pressed outwards by a spring 18, and the operator
has to press in this key 17 after each time of depressing the "signal
5 on" key 2 before he can depress the "signal off" key 3, and his strict
instructions will be not to press in this key 17 until he shall have received
the proper clectric signal from the succeeding station O, showing tho
portion of line to that station, that is, from B to C to be clear.
"
In working the apparatus in ordinary cases the "signal off" key 3
will be depressed when an approaching train is two sections distant as
notified by electric signal; on the train passing the next station the
"signal on key 2 will be depressed, and on the train passing the
station itself the signalman immediately after putting his actual
semaphore signal at "danger" will press in the relieving key 17, in
5 readiness for depressing the "signal off" key 3 on the approach of the
next train.
The intention and effect of my improved system of signalling is that a
clear section of the line between two successive block stations or signal
cabins will always be interposed between a train and one following it.
) In other words a succeeding train or engine will not (except on special
occasions and with special precautions) be allowed, as heretofore to
proceed up to the danger signal next immediately behind the proceeding
train, but only up to the signal which is a section further back.
When using a slide for covering the "signal off" key 3 I have it and
the parts in connection with it fitted, according to ono modification, in o

page_text: distinct releasing movement, substantially as and for the purposes herein-
before described.
In witness whereof, I, the said Robert Currer, have hereunto
set my hand and seal, this Third day of February, in the
year of our Lord One thousand eight hundred and seventy-
five.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
R. OURRER. (L.S.)