IMPROVEMENTS IN RAILWAY SIGNALLING AND IN APPARATUS THEREFOR.
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Thomas Gaddes at the Office of the
Commissioners of Patents on the 8th March 1882.
THOMAS GADDES L.D.S Eng. & Edin. of 46 Seymour Street Portman Square
in the County of Middlesex. IMPROVEMENTS IN RAILWAY SIGNALLING AND IN
APPARATUS THEREFOR.
This invention relates to certain improvements in the automatic signalling on
the absolute "block" principle, the signals being actuated by an engine passing
given points.
By the weight, or the impact, or the contact of the engine or train acting
either mechanically or upon an electric apparatus the signals are worked and
any given section or sections of railway road or space will be "blocked" and
"cleared."
At the same time there is automatically and coincidently with the blocking or
clearing of any section or number of sections of railway or road space recorded
within the signal cabin or cabins a permanent and visible indication of the
condition of the section whether "blocked" or
"clear" or " train on."
The mechanism which acts upon the signals is composed chiefly of a cylinder
open at both ends; at each end of the said cylinder two short tubes closed at one
extremity are placed and so as to slide in telescopically the two said tubes are
attached one to the other by means of a spiral spring one of which tubes is to
receive the action of a counterweighted lever which through a rod bar or chain is
actuated by the mechanism an incline stop and connections, lever arm catch or
electric button placed near the rail and upon which the engine or train when
passing will act. The second tube by means of the spiral spring will act at a
given moment on a counterweighted bell crank which through a rod raises or lowers
the signal arm or semaphore; the said crank is maintained in its normal position
by a counterweighted lever which is operated by another counterweighted lever
which latter is attached by means of a rod bar or chain to a second mechanism
placed on the railway near the rails at a certain distance from the first one.
At one end of the cylinder where the first tube is placed a catch is fixed which
catch serves to press upon the tube in order to prevent the latter standing out from
Di 11

page_text: the cylinder when the pushing in action of the counterweighted lever has ceased;
the said catch may be released from its position by a lever which by means of a
rod, bar or chain receives action from a third mechanism placed upon the railway
at a certain distance from the second one, and upon which the engine or. train will
act when passing.
The system operates as follows:
As the engine or train leaves the station it acts to raise the signal of the station.
As soon as it passes the first actuating mechanism placed on the railway and
connected to the signal above described which I call signal No. 1, the cylinder or
motor is charged that is to say the tube is pushed into the said cylinder pressing
the spiral spring, and is maintained, in this position by the catch. At a given
distance say 200 or 300 yards the wheels of engine or train actuates the second
mechanism placed near the rail which causes the signal No. 1 which is now in the
rear to be raised upon the motor being liberated and the second tube extending
out from the cylinder through the second connections and the counterweighted
levers, the spiral spring is then only half exhausted; at the same time the spiral
spring of the signal of the station is discharged by the catch being raised and the
said signal is thereby lowered.
At any distance ahead, say a mile, there is fixed a second signal No. 2 the
spiral spring of which is similarly charged as the engine or train passes, and the
given distance say 200 or 300 yards beyond there is the actuating mechanism to
raise the signal.
At the same time that the signal No. 2 is raised the signal No. 1 is lowered
through the third mechanism and the catch being liberated and the spiral spring
is entirely exhausted
In this way any number of signals which may be placed between the existing
cabins of any "block" can be worked in relation with one another.
As each of the several signals is raised and lowered there is recorded by an
electric tell-tale in the cabin the respective conditions of the several sub-sections,
whether "blocked" or "clear."
Should an engine attempt to pass a signal while at danger a gong acted by a
device attached to the crank lever is sounded and thus an efficient "fog-signal" is
provided.