AN IMPROVED SYSTEM OF COMMUNICATION BETWEEN RAILWAY PASSENGERS AND THE GUARD AND ENGINE DRIVER OF A TRAIN
Year: 1869

page_text: PROVISIONAL SPECIFICATION left by William Johnson at the Office
of the Commissioners of Patents, with his Petition, on the 21st
April 1869.
I, WILLIAM JOHNSON, of the Elms, Sketty, Swansea, in the County
of Glamorganshire, South Wales, Gentleman, do hereby declare the
nature of the said Invention for "AN IMPROVED SYSTEM OF COMMUNICATION
BETWEEN RAILWAY PASSENGERS AND THE GUARD AND ENGINE DRIVER OF A
TRAIN," to be as follows:-
The mechanical arrangement is contained in a small box, which can
be readily attached to a carriage on the roof or flooring, and consists of
two bell cranks placed close to each other somewhat in the form of
the letter W, each crank having an upright tongue, to which a wire
running from end to end of the carriage is firmly attached, so that any
vibration of the tongue would produce a corresponding motion of the
wire. The two central points of the cranks support a small block, from
which depends a cord passing into the compartment of the carriage;
this cord is also connected with another wire running across the carriage

page_text: at right angles with the one before mentioned, which works a semaphore
on either or both sides of the carriage. Each carriage or compartment
being fitted with this bell-crank arrangement, it only remains to con-
nect the wires of the several carriages to place a train in communication
from end to end, and this connection is thus effected :-A bar jointed in
the centre to form a V is used as a coupling between two carriages.
The two ends attached to the carriages are also jointed to allow the V to
expand or contract with the action of the carriages; or the bar may
be made with more joints. In either case the wire from one carriage
is carried across such a bar, passing through a number of friction rollers
to the next carriage, where it is to be connected with the other wire,
and so on along the entire line, terminating on one side with a bell or
alarum in the guard's van, and on the other with a similar signal near
the driver. By this arrangement the tension of wire necessary for
rapid signalling is in no ways effected by the play of the carriages. A
pull of the cord in a carriage releases the block to which it is attached
from its resting place over the central points of the bell cranks, drawing
those points downwards (where the arrangement is to the roof) and
forcing the opposite points against the tongues, which acting on the wire
at opposite angles would at once communicate motion to the bells at
both extremities. The dropping of the block also acts upon the
semaphore, the position of which, as well as that of the cord inside
the carriage, would at once indicate the place from which the alarm has
been given. The block has to be replaced in its position before the
alarm can be given from the same compartment or carriage again;
but the communication remains open to the other carriages, and the
guard and the driver can signal to one another without interfering with
the carriages or with the semaphores.
It is not necessary to the efficiency of this system that the block
should be dislodged and the particular box thrown out of gear; this can
be avoided by attaching the end of the cord to the central points of
the cranks, but in such case the semaphore would alone indicate the
compartment from which the alarm has been given.
The features of novelty in this arrangement are,-
1stly. The employment of two bell cranks, each having a tongue
for supporting the wire, and otherwise arranged in the manner
desovihad

page_text: 2dly. The use of a jointed coupling bar fitted with friction rollers
for carrying the wire across the gaps between the carriages, and to
these I lay special claim.