An Electrical Parcel Exchange System.
Year: 1891

page_text: Date of Application, 30th July, 1891
Complete Specification Left, 30th May, 1892-Accepted, 30th July, 1892
PROVISIONAL SPECIFICATION.
An Electrical Parcel Exchange System.
I, ALFRED ROSLING BENNETT, of 22, St. Alban's Road, Harlesden,
London, N.W., Electrical Engineer, do hereby declare the nature of this invention
to be as follows:---
The object of my invention is to provide a means by which parcels and small
packets of goods or other material, including letters, correspondence and analogous
matters, may be delivered and interchanged between warehouses, places of business,
factories, private residences, post-offices and other buildings situated in different
localities of a city or town or its suburbs by means of small carriages operated by
electro-motors and run on rails or other suitable guides contained in iron pipes or
brick culverts or conduits laid below the surface of the streets, or in some instances
supported on pillars above the surface of the ground, or attached to walls or
buildings. Such pipes, culverts or conduits are hereinafter referred to as tunnels.
To carry out this system I lay lengths of such tunnels along the street, road or
route best calculated to secure suitable admission to the buildings participating in
the parcel exchange service. The tunnel may contain two tracks or lines of rails,
or an up and down track may be contained in separate tunnels. In the first-case
the tracks may be laid not on the bottom of the tunnel but on bridges preferably
of insulating material placed at proper intervals, so that a clear space would remain
below the tracks in which could be laid the necessary electrical conductors, wires, etc.,
and which space would also be available for the laying of electric light conductors,
telegraph and telephone wires, gas and other pipes not necessarily connected with
the parcel exchange system. The system does not absolutely require two tracks ;.
a single track with passing places at intervals might be used. When two tracks
are employed they may advantageously be placed one above the other in the same
tunnel, as the working of sidings to the right and left will thereby be much
facilitated.
The method of operation would be as follows:-There would be established in a
suitable locality, and in the case of a large town, in several suitable localities, a
central station to which all the tunnels operated from that station would be brought,
and where would be situated the engines and dynamos requisite for the generation
of the current needed to work the carriages, switches, and other devices. This
central station could also be utilised as an electric light and power generating
station with advantage, or as a telephone exchange, since the tunnels for the parcel
exchange service would as hereinbefore mentioned also serve to contain electric
light and power and telephone conductors.
Connection would be made with the buildings of subscribers to the system by
means of short sidings diverging from the main tunnels. These sidings would
contain branches from the tracks or rails, and would be continued into any suitable
portion of the subscriber's premises. At the junction of the branches with the
main tracks switches similar in principle to the switches of a railway would be
placed, which switches could be operated by electro-motors or electro-magnets
under the control, by means of wires and electric currents, of the operator at the
central station. In certain circumstances a joint or separate control could also be
given to the subscriber.
As there would be many branches from the main track on each line of tunnel, it
is necessary to enable the operator at the central station to work any switch he may
desire without interfering with the others. This may be accomplished in several
ways of which the principal are hereinafter indicated.
Firstly, any switch may be found and operated by means of a continuous

page_text: conductor running out from the central as far as the most distant switch. A branch
from this conductor is taken through the electro-magnet or other controlling device
of each switch and thereafter returned to the central by a separate conductor. The
operator will thus be able to work any of the switches at will by closing the circuit
of its return conductor.
Secondly, the switches may be controlled by musical reeds, tuning-forks or other
vibrators of different pitches, kept in constant motion at the central and arranged
to send currents at will into a conductor communicating with vibrators placed at
the different switches. Each vibrator at the central will operate only that vibrator
which corresponds to itself in frequency as is well understood by electricians.
Consequently, if a vibrator of different pitch is assigned to each switch the
operator can find that switch by sending currents from the, vibrator at the central
corresponding to it. The switch vibrator being set in motion will close a contact
by means of which a current from the central can be sent through the electro-
magnet or other device controlling the switch. The fact that such a contact has
been closed may be signalled back to the operator by means of a return wire and a
shutter or other device bearing a name or number.
Thirdly, the switches may be found by step-by-step instruments at the central
operated either by voltaic or magneto currents, such instruments resembling the
Wheatstone, Breguet and Siemens' A B C telegraphs. Dials corresponding to the
receivers of such telegraph instruments would be placed at the switches and
arranged to close contacts through which the currents working the switches may
be sent.
Fourthly, the switches may be found by means of a system of pendulums or
rheotomes such as is employed in the telephonic individual call-system of Messrs.
Brown & Saunders, of Mr. Johnston Stephen and other inventors, the feature of
which is that a controlling pendulum is used at the central station, the rate of
vibration of which can be altered by the operator at will by simply shifting a
weight higher or lower on the stem of the pendulum. According to a well-known
law, when a pendulum controlling electric currents is joined in circuit with other
pendulums, only those pendulums which have the same rate of vibration as the
sending pendulums will obey the electric impulses received from the sending
pendulum. If, therefore, there are included in an electric circuit several pendulums
having different rates of vibration, any one of these can be set in motion from the
central station by altering the weight on the sending pendulum to agree with the
rate of vibration of the receiving pendulum it is desired to set in motion, and a
contact closed, through which the desired switch can be shifted.
Of the several devices I prefer the first, and shall hereinafter adopt it for the
purpose of describing my invention. I shall likewise assume that two tracks are
used placed one above the other in the same tunnel, the down track occupying the
lower position.
The trucks run upon four or more wheels, two or more of which are geared to an
electro-motor carried by the truck, which motor collects its current by means of a
rubbing or rolling contact, from a conductor running parallel to the tracks. Each
truck carries two sets of collecting contacts, one for use on the down journey when a
it travels below the parallel conductor and the other for use on the up journey when
it travels above it. Or a shifting contact that can be adjusted to either position
may be employed. The propelling current is supplied to the parallel conductor
from the central station, and is under the control of the operator who by means of
switches can regulate its strength or cut it off altogether.
The switches operating the sidings into subscribers' buildings may be arranged
in various ways. They may be kept in position for through main-line traffic by
means of springs or permanent magnets and be shifted to connect with the sidings
by a current sent from the central, resuming their normal position as soon as the
current ceases, or they may be wrought entirely by electricity, a current of one
sign shifting them and a current of opposite sign restoring them to normal
position.
5

page_text: The sidings into subscribers' buildings consist of down and up track, one above
the other, but when space is available these are caused to diverge after entering the
building and ultimately to unite in one track so that trucks may be shifted from the
down to the up track without lifting them bodily from one to the other.
The parallel conductor on the down track is preferably not carried into the
subscriber's building, but is stopped short at a point within the tunnel, and the
truck should, if practicable, be made to finish its journey from this point by
the momentum it has acquired, assisted when possible by a descending grade. This
is a precaution against the subscriber endeavouring by mistake to return a truck
on the down instead of on the up track.
On entering the building the truck has its speed reduced by a succession of
obstacles or catches formed of the rails themselves or placed alongside them, which
obstacles or catches are pressed up by springs. A suitable projection on the truck
engages with the obstacles or catches, and in passing them has to depress the
springs. When the speed with which trucks ordinarily arrive has been ascertained
it will be possible to regulate the springs so as to bring trucks to a stand in any
desired position. The obstacles or catches may be fitted with contacts so that they
will close the circuit of an electric battery and bell when depressed, and so serve to
announce the arrival of a truck. The obstacles or catches are an additional
precaution against a truck being returned on the wrong line, since they are intended
to be depressed by the truck in one direction only and to oppose any attempt to
push a truck in the wrong direction on the down line.
The subscriber's siding terminates in a stop-block or buffer of an elastic nature
against which an arriving truck will run should it not previously be stopped. An
electrical contact may be fitted to the buffer which may be used to announce a
truck's arrival. After striking the buffer a truck will be prevented by the obstacles
or catches from rebounding and running back into the tunnel.
The conductor which carries the current for operating the switches controlling
sidings is led through a contact on each siding placed a few trucks' lengths away
from the main line. This contact is arranged to be temporarily broken by the
passage of a truck. By means of a galvanometer, or other indicating device, placed
in the circuit of the same conductor the operator will know when a truck has entered
its proper siding, and is clear of the main line, since the breaking of the contact
will actuate the indicating device. The actual arrival of a truck in the subscriber's
building could also be signalled to the central by means of the buffer contact or
those connected with the obstacles or catches.
Each subscriber may with advantage be connected to the central by telephone,
telegraph or electric bell.
The method of working a down-line consignment is as follows:-―
The operator at the central places the truck or train of trucks on the down line
at the entrance of the tunnel so that the collecting contact of at least one of the
trucks presses against the parallel conductor carrying the propelling current.
Having ascertained by one or other of the methods hereinafter described that the
section of the main line over which the truck or train is to travel is clear, he notifies
the consignee, if he is connected by telegraph or telephone, that a train is leaving
for him; turns on the propelling current to the required degree, and by means of
the conductor connected with the switch of the consignee he sets the switch in the
position for shunting into the consignee's siding. On arriving at the switch the
truck or train turns into the siding, and by breaking the contact in the switch-
current circuit notifies the operator that it has done so, and that the main line is
clear. The operator thereupon restores the switch to its normal position. The
truck or train runs into the subscriber's building where it is gradually brought up
by the obstacles or catches and finally strikes the buffers, announcing its arrival by
ringing a bell.
.
The up track at the subscriber's end is arranged substantially in the following
manner :-
Preferably it is connected with the down track in such a way that trucks can be

page_text: transferred from the down to the up track without lifting them clear of the rails.
The parallel conductor carrying the propelling current is brought into the building
sufficiently far to admit the collectors of one or more trucks being placed against it,
but the portion of the conductor so brought in is not in permanent electrical
connection with the main portion of the conductor, but is effectually insulated from
it until the operator at the central station is ready to admit the truck or train to the
main line.
At the entrance of the tunnel the up track is obstructed by a projection from the
armature of an electro-magnet, the projection being of sufficient solidity to resist
any attempt to push the truck or train past it. The electro-magnet is in circuit
with a conductor resembling that which controls the switches on the down line.
The armature of the electro-magnet is in connection with the conductor carrying
the propelling current, and is so arranged that when the armature is attracted
to the poles of the electro-magnet a connection is formed between the main
portion of the conductor and the small length which projects into the subscriber's
building.
The method of working an up-line consignment is as follows:-
The subscriber places the truck to be forwarded at the entrance of the tunnel
against the projection from the electro-magnet armature, and so that the collecting
contact of the truck presses against the portion of the parallel conductor within his
building but which does not at present carry any current.
If connected with the central by telephone or telegraph he next signals the
operator that he has a truck or train ready to despatch. If the main-line is clear
the operator thereupon sends a current through the coils of the electro-magnet
The armature
controlling the obstructing projection at the entrance of the tunnel.
is thereupon attracted, a movement which has the double effect of removing the
obstructing projection and communicating propelling current to the portion of the
parallel conductor hitherto insulated. The electro-motor on the truck immediately
revolves, and the truck enters the tunnel. The up siding communicates with the
main line by a switch resembling the catch points on an ordinary railway, which is
opened by the wheels of the truck itself, which thereupon travels along the main up
track till it reaches the central station where it is brought up by suitable devices,
such as those already described, or by causing an axle or other part of the truck to
engage with a hook and chain attached to a spring or weight.
The switches on the down track and the obstructive electro-magnets on the up
track may be worked by the same set of conductors if reversed currents are
used, the switches being operated by the current of one sign and the electro-
magnets by that of the other.
On the up journey the truck motors must necessarily run in the reverse direction
to that in which they rotated on the down. The collecting contacts must be
arranged accordingly to lead the current through the motors in the required
direction. The arrangement by which separate collecting contacts must be used
for the down and up journeys is an additional safe-guard against a subscriber
sending a truck into the tunnel on the down track, since the truck as soon as it
found current would run back into his building.
When trucks are coupled together the resulting train must not be longer than
the siding of the subscriber for whom it is destined.
The rails on which the trucks run if insulated from the earth and from each
other may be used as conductors for carrying some of the currents required for the
working of the system, or they may be made to complete the circuit of the
propelling current either metallically or through the earth.
When one subscriber wishes to send a parcel to another he despatches it in the
first instance to the central station where the operator reads the address and
forwards it to the consignee's siding.
Should a truck by mistake be delivered to the wrong siding the subscriber
has only to transfer it to the up track and return it to the central.
In order that a continual stream of traffic may be maintained, it is advisable

page_text: that the operator should have means of knowing the position of a truck in the
tunnel and of following its progress out or home. This may be managed in several
ways.
If one of the rails on either track is in continuous electrical contact throughout
and the other rail is divided at intervals by small insulating spaces and the
sections thus formed are connected to the central station by separate wires, each
having a galvanometer; shutter or other indicating device in its circuit, a current
kept on the continuous rail at the central station can be transferred by the wheels,
axles or body of the truck, or by a special rubbing contact, successively to the
sections of the divided rail so that as the truck moves along each indicator at
the central station will in turn be affected and the operator can follow with his
eye the progress of the truck along the track.
The indicators may take the form of miniature railway semaphore signals
operated by electro-magnets, the arm of the semaphore connected with the section
on which the truck is running being kept horizontal, that is to say, at danger,.
while the others will indicate line clear except when the truck is actually on them.
Instead of using one rail to conduct a current from the central station for this
purpose a separate wire may be used from which the truck would pick up current
by means of a travelling contact. Or the current from the central may be sent
through the indicators to the sections of the divided rail if the truck were arranged
to earth each section successively as it goes along either by means of the other rail
or a travelling contact.
Should a truck through any accident stop in the tunnel, the indicator of the
section it is on will remain continuously at danger, and the operator will know that
such a stoppage has taken place, together with its position, and take steps to
remove it. For instance, he can send an empty truck forward, the speed of which
can be reduced to a minimum as it approaches the disabled truck by modifying the
propelling current, until it strikes against the disabled vehicle, when full current
can be turned on, and both trucks forwarded to the consignee, or shunted at the
next convenient siding, preferably at a siding at which there is telephonic communi-
cation, so that the subscriber can be asked to transfer both trucks to the up line
and return them to the central coupled together.
The position of trucks may also be indicated to the central station by magneto.
telephones or microphones placed at intervals in the tunnel as the noise made would
be conveyed thither telephonically. Another method would be to cause the truck
to make successive contacts as it moves along which would be registered on a step--
by-step dial or other device at the central. The trucks could likewise be made to
indicate their position by carrying electrical vibrators or reversers which would act
electrostatically on conductors in connection with the central station, or on condensers.
or coils of wire placed at intervals along the tracks and connected by wires to the
central.
These indicating devices are applicable to both the down and up tracks, so that
the operators at the central will always be advised of the movements of trucks.
If the sections are made each one hundred yards long a pair of expert operators,
one for each track could keep a constant stream of trucks circulating as many as
seventeen on the down and seventeen on the up track being possible on a line one
mile long.
Although each subscriber could advantageously be connected telephonically or
telegraphically with the central station such a connection is not necessary. Trucks,.
as already described, would announce their own arrival in the subscribers' buildings,.
and subscribers could place trucks on the up line ready for despatch which the
operator could withdraw when convenient without troubling the subscriber further.
During lulls in the announced traffic, or at prescribed intervals during the day,
the operator could tap the various sidings along the route, and any trucks ready
would at once be brought into the central. As soon as it reached the main-line a
truck so withdrawn from a siding would show its presence on the up track by the
operation of one or other of the indicating devices hereinbefore described.

page_text: If required, trucks could be automatically tilted and unloaded on arriving in a
subscriber's building and afterwards withdrawn as empties by the operator without
any attention on the part of the subscriber.
The subscribers can be supplied with empty carriages during the night or slack
hours of the day by the operator at the central station without the personal
attendance or attention of the subscriber or his servants. Thus a subscriber
whose traffic requires a certain number of carriages every day will find them
ready in his siding every morning. In the event of a subscriber having used
all his empties and requiring more, he will be able, if suitably connected, to
signal the fact to the operator at the central station who will supply him with
the necessary empty carriages at the first lull in the traffic.
At the central station obstructive catches interlocked with the levers operating
the subscribers' siding switches may be arranged if desired so that a truck placed
ready for despatch cannot be sent off until the siding it is destined for has been
placed in connection with the main-line.
In lieu of picking up the necessary propelling current from a conductor or
conductors laid along the track, the carriages may receive motion from a voltaic
battery or set of accumulators carried with them.
In the event of two or more central stations being required in the same town,
those two or more stations would be connected with each other by a sufficient
number of tunnels. On the operator at one such central station receiving from a
subscriber packets or parcels which cannot be delivered direct through the medium
of the tunnels diverging from that station, he will in the first case forward
them to the other central station by means of the connecting line.
It is evident that by the system I have hereinbefore described a continuous
circulation of parcels can be maintained, and deliveries of letters and parcels
from the post-office of the town can be effected by having a branch into that
building, while parcels or letters for despatch by post, or telegrams written out
for despatch by telegraph together with the money necessary to defray the cost of
forwarding such parcels, letters or telegrams, can be conveyed to the post-office
from subscribers' buildings.
In lieu of trucks running on rails trucks suspended from rails as in the late
Professor Jenkins' system of telpherage may be employed, the details being
modified accordingly.
The tunnels may be constructed of any dimensions as the scale on which the
invention may be carried out may vary within wide limits, but the tunnels should
preferably be constructed of sufficient size to admit of a man creeping through or
being carried through lying on a specially-constructed truck. To facilitate
inspection and repairs when the two tracks are contained one above the other in the
same tunnel the upper or up line should not be supported on bridges stretching
across the tunnel but on brackets fastened to the walls of the tunnel and extending
from them only sufficiently far enough to support the rails.
DT
1
1001
A. R. BENNETT.
COMPLETE SPECIFICATION.
An Electrical Parcel Exchange System.
I, ALFRED ROSLING BENNETT, of 22, St. Alban's Road, Harlesden,
London, N.W. Electrical Engineer do hereby declare the nature of this inventiou
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
The object of my invention is to provide a means by which parcels and packets
of goods or other material, including letters, correspondence and analogous matters,
may be delivered and interchanged between warehouses, places of business,
factories, private residences, post offices, railway stations, and other buildings

page_text: '
situated in different localities of a city or town or its suburbs by means of carriages
operated by electro-motors and run on rails or other suitable guides contained in
iron pipes or brick culverts or conduits of any appropriate description laid below
the surface of the ground or in some instances supported on pillars or otherwise
above it, or attached to walls of buildings. Such pipes, culverts or conduits are
hereinafter referred to as tunnels.
To carry out this system I lay lengths of such tunnels along the street, road or
route best calculated to secure suitable admission to the buildings participating in
the parcel exchange service. The tunnel may contain two tracks or lines of rails,
In the first case
or an up and down track may be contained in separate tunnels.
the tracks may be laid not on the bottom of the tunnel but on bridges or brackets,
which may be of insulating material, placed at suitable intervals, so that a clear
space may be left below the tracks in which can be laid the necessary electrical
conductors, wires, etc., and which space would also be available for the laying of
electric light conductors, telegraph and telephone wires, gas and other pipes not
necessarily connected with the parcel exchange system. Two tracks are not
absolutely essential; a single track with passing places at intervals might be used.
When two tracks are employed they may advantageously be placed one above
the other in the same tunnel as the working of sidings to the right and left will
thereby be much facilitated. The mode of operating such a system would be
as follows:-
There would be established in a suitable locality, and, in the case of a large
town, in several suitable localities, a central station into which all the tunnels
operated from that station would be brought, and where would be situated the
engines and dynamos requisite for the generation of the current needed to work
the carriages, switches and other devices. This central station could also be
utilised as an electric light and power generating station with advantage, or as a
telephone exchange, since the tunnels laid for the parcel exchange service would,
as is hereinbefore mentioned, also serve to contain electric light and power and
telephone conductors.
Connection would be made with the buildings of subscribers to the system by
means of short sidings diverging from the main tunnels. These sidings would
contain branches from the tracks or rails, and would be continued into any suitable
portion of the subscriber's premises. At the junction of the branches with the
main tracks switches similar in principle to the crossing switches of an ordinary
railway would be placed, which switches could be operated by electro-magnets or
electro-motors under control, by means of wires and electric currents, of the
operator at the central station. In certain circumstances a joint or separate control
could also be given to the subscriber.
As there would be many branches from the main track on each line of tunnel, it
is necessary to enable the operator at the central station to work any switch he may
desire without interfering with the others. This may be accomplished in several
ways of which the principal are hereinafter indicated.
Firstly, any switch may be found and operated by means of a continuous
conductor running out from the central as far as the most distant siding switch.
A branch from this conductor is taken through the electro-magnet, or electro-motor
or other controlling device of each switch and thereafter returned to the central
by a separate conductor. The operator will thus be able to work any of the siding
switches at will by closing the circuit of its return conductor which he has under
his command at the central. This is the device, which is hereinafter more
particularly described, which I prefer to employ as being the most simple and the
least liable to derangement. It is a plan, however, that involves the use of a
separate return wire all the way to the central from each switch.
By the use of any of the three following devices it is possible to arrange so that
one outward and one homeward conductor will suffice, the electro-magnets con-
trolling the siding switches being connected between them in derivations or shunts,
each such derivation or shunt containing a circuit-closer worked by an electro-

page_text: magnet which is controlled at the central station by means of one or more auxiliary
-conductors having either metallic or earth returns. The siding switches are kept
normally closed by springs and are opened by the passage of a current from the
central station through the electro-magnets which, when so excited, overcome
the pull of the springs. The main conductor between which these electro-magnets
are bridged are kept connected at the central station to the poles of a suitable
source of electricity, such as a primary or secondary battery or a dynamo, so that
the operator has only to close the electro-magnetic circuit-closer of the switch he
desires to work to cause a current to flow and the switch to open. Subsequently
by interrupting the circuit, the switch is allowed to resume the closed position
under the influence of the springs. Each electro-magnetic circuit-closer may
have a separate conductor, or several or all of them may be served by one
.conductor. In the latter case the attendant at the central station must
be provided with suitable apparatus for finding the circuit-closer he wants
preparatory to closing it. Such finding apparatus may be of several kinds. For
instance, the armatures of the electro-magnetic circuit-closers may be musical reeds,
tuning-forks or vibrators of different pitches which, as is well known to electricians,
will only respond to vibratory currents of the same frequency as their own specific
rate of vibration. Each such reed, fork or vibrator has its counterpart at the central
arranged to make and break at will in the circuit of the conductor controlling the
electro-magnetic circuit-closers and a suitable battery. A circuit-closer is found by
sending a vibratory current of its own frequency through the line; its armature
closes the circuit of the electro-magnet controlling the siding switch, which is
thereupon opened and so continues until the circuit-closer is put out of action by
the cessation of the exciting current. According to another plan the armatures
of the electro-magnetic circuit-closers may consist of pendulums or rheotomes each
having a different rate of vibration. In this case the operator at the central is
provided with corresponding pendulums, or with one pendulum, the rate of
vibration of which he can alter at will by shifting a weight or bob on the
pendulum shaft. As with the reeds, a particular switch is found by sending
electrical impulses corresponding to its rate of vibration into the line, and the
method of operation is in every respect similar. By another plan the switches
may be found by means of step-by-step instruments operated by voltaic or magneto
currents, such instruments resembling in general character the A B C telegraphs
of Wheatstone, Bréguet, and Siemens. At the central the sending portion of such
an instrument would be placed and the electro-magnetic circuit-closers would be
represented by the receiving portions. At each switch a needle would travel
round a dial in obedience to the motions of the sending lever worked by the
attendant and in one position only, different in each switch, would close a
contact through which the current operating the electro-magnetic switch controllers
would find its way. With this plan it would be preferable not to permit this
current to flow to line until the switch has actually been found and the contact
closed. The siding switches may be distinguished on the sending dial by signs,
letters or numerals.
In all the plans described above it is practicable to operate the siding switches
by breaking instead of closing contacts. By such a method the siding switches must
be kept closed by electro-magnets excited by permanent currents kept always on
the line and opened by interrupting such currents and allowing springs pulling
against the electro-magnets to act. In such a case the electro-magnetic circuit-
closers hereinbefore described must be replaced by electro-magnetic contact-breakers.
For the purpose of more readily describing my invention I shall hereinafter
.assume that the two tracks are placed one above the other in the same tunnel, the
-down track, except when otherwise stated, occupying the lower position.
The trucks run upon four or more wheels two or more of which are geared to an
electro-motor carried by the truck, which motor derives its current by means of a
travelling contact from an insulated conductor fixed parallel to the tracks. Each
truck carries two sets of collecting contacts one for use on the down journey when

page_text: it travels below the parallel conductor and one for use on the up journey when it
travels above it. Or a shifting contact that can be adjusted to either position
may be employed. The propelling current is supplied to the parallel conductor at
the central station and is under the control of the operator there who by means
of switches can regulate its strength or cut it off altogether. Under some of the
possible arrangements of the working parts additional travelling contacts must be
attached to the trucks for the purpose of leading away to earth or to a return
conductor the current after it has operated the motor.
The switches or points which direct trucks into subscribers' sidings may be
arranged in various ways. They may be kept in position for through main line
traffic by means of springs or electro or permanent magnets, and be shifted to
connect with the sidings by a current sent from the central, resuming their normal
position as soon as the current ceases, or they may be worked entirely by
electricity, a current in the one direction opening, and in the other restoring to
normal position.
The sidings into subscribers' buildings consist, like the main tunnel, of down
and up tracks, one above the other, but when space is available these are
caused to diverge after entering the building and ultimately to unite in one track
so that trucks may be shifted from the down to the up line without lifting them
clear of the rails. Or the transfer may be effected by means of a movable
platform.
The parallel conductor on the down track is preferably not carried into the
subscriber's building but is stopped short at a point within the tunnel and
the truck should, if practicable, be made to finish its journey from this point by
the momentum it has acquired, assisted, where possible, by a descending grade.
This forms a precaution against a subscriber endeavouring to return a truck on the
down instead of the up track.
On entering the building the truck has its speed reduced by a succession of
obstacles or catches formed by the rails themselves or placed alongside them,
which obstacles or catches are pressed up by springs. A suitable projection on the
truck engages with these devices, depressing them in passing against the pressure
of the springs.
When the speed with which trucks ordinarily arrive is known it
will be possible to regulate the springs so as to bring trucks to a stand at any
desired point. These retarding devices may be fitted with electrical contacts, and
so made to announce the arrival of a truck in a subscriber's station. By rising
behind the truck after it has passed they prevent it running or being improperly
pushed back on the wrong line. The sidings may terminate in an elastic buffer
against which an arriving truck will run, should it not previously have been
stopped. To such buffers electrical contacts closed by the impact of the truck
may be fitted.
The conductor which carries the current for operating the siding switches is led
through a pair of contacts placed on each siding a few trucks' length from the main
line. These contacts are arranged so that they are temporarily separated by the
passage of a truck. By means of an indicator placed as the central in the circuit
of the same conductor the operator will know when a truck has entered its proper
siding and is clear of the main line, since the breaking of the contacts will actuate
this indicator. The arrival of a truck in a subscriber's station may be signalled to
the central in much the same manner, the contacts operated by the blocking
devices and the buffer-stop being available for this purpose.
The method of working a down truck or train is as follows:-
:-
The operator at the central places the truck or train of trucks on the down line
at the entrance of the tunnel so that the travelling contact of at least one of the
trucks presses against the parallel conductor carrying the propelling current.
Having ascertained by, one or other of the methods to be hereinafter described that
the section of the main line over which the truck or train is to travel is clear he
notifies the consignee, if he is connected by telephone or telegraph, that a train is
leaving for him; turns on the propelling current to the required degree and by
त

page_text: means of the conductor connected with the siding switch of the consignee he sets
the switch in the position for shunting into the consiguee's siding. On arriving at
the switch the truck or train turns into the siding, and by breaking the contact
in the circuit operating the siding switches notifies the operator that it has done so
and that the main line is clear. The operator thereupon restores the switch to its
normal position by causing the current to cease. The truck or train runs into the
subscriber's station where it is gradually brought up by the retarding devices
already mentioned and announces its arrival by ringing a bell.
The up track at the subscriber's station is arranged substantially in the following
manner :-
Preferably it is connected with the down track in such a way that trucks can be
transferred from the down to the up line without lifting them off the rails. The
parallel conductor carrying the propelling current is brought into the building
sufficiently far to admit of the collector of one or more trucks being placed against
it, but the portion of the conductor so brought in is not in permanent electrical
connection with the main portion of the conductor but is effectively insulated from
it until the operator at the central is ready to admit the trucks or train to the
main line.
At the entrance of the tunnel the up track is obstructed by a projection from
the armature of an electro-magnet, the projection being of sufficient solidity to resist
any attempt to push a truck past it. The electro-magnet is in circuit with a
conductor resembling that which controls the siding switches on the down line.
The armature of the electro-magnet is in connection with the conductor carrying
the propelling current and is so arranged that when the armature is attached to the
poles of the electro-magnet a connection is formed between the main portion of that
conductor and the short length which projects into the subscriber's station.
The method of working an up-line consignment is as follows:-
The subscriber places the truck to be forwarded at the entrance of the tunnel
against the projection from the electro-magnet armature and so that the collecting
contact of the truck presses against the portion of the parallel conductor within his
station but which does not at present carry any current. If connected to the.
central by telephone or telegraph he next signals the operator that he has a train
ready to despatch. If the main line is clear the operator thereupon sends a current
through the coils of the electro-magnet controlling the obstructing projection at the
entrance of the tunnel. The armature is thereupon attracted, a movement which
has the double effect of removing the obstructing projection and communicating
propelling current to that portion of the parallel conductor hitherto insulated. The
electro-motor on the truck immediately revolves and the truck enters the tunnel.
The up siding communicates with the main line by a switch resembling the catch
points on an ordinary railway which is opened by the wheels of the truck itself,
which thereupon runs upon the main up track till it reaches the central station
where it is brought up by suitable devices such as those already described.
On the up journey the truck motors must necessarily run in the reverse direction
to that in which they rotated on the down. The collecting contacts must be
arranged accordingly to lead the current through the motors in the required
direction. The arrangement by which separate collecting contacts must be used
for the down and up journey is an additional safe-guard against a sender
endeavouring to forward a truck into the tunnel on the wrong track since as soon
as it found current it would run back into the station.
When trucks are coupled together the resulting train must not be longer than
the siding of the subscriber for whom it is destined. The rails on which the
trucks run if insulated from the earth and from each other may be used as
conductors for carrying some of the current required for working the system, or
they may be made to complete the circuit of the propelling current either
metallically or through the earth. When one subscriber wishes to send a parcel
to another he despatches it in the first instance to the central where the operator
reads the address and forwards it, either in the same truck or another, to the

page_text: consignee's siding. Should a truck by mistake be delivered to the wrong siding
the subscriber has only to transfer it to the up track and return it to the
central.
If
In order that a continual stream of traffic may be maintained it is desirable that
the operator should have means of knowing the position of a truck in the tunnel and
of following its progress out or home. This may be managed in several ways.
one of the rails on either track is in continuous electrical contact throughout and
the other rail is divided at intervals by small insulating spaces and the sections thus
formed are connected to the central station by separate wires each having an
indicating device in its circuit, a current kept on the continuous rail at the central
can be transferred by the wheels, axles or body of the truck, or by a special
rubbing contact, successively to the sections of the divided rail so that as the truck
moves along each indicator at the central will in turn be affected and the operator
can follow with his eye the progress of the truck along the track.
Instead of using one rail to conduct a current from the central for this purpose a
separate wire may be employed from which the truck would pick up current by
means of a travelling contact. Or the current from the central may be kept on
all the sections of the divided rail, and returned by the continuous rail or by
the earth.
Should a truck stop in the tunnel the indicator of the section it is on will remain
deflected and so warn the operator that such a stoppage has taken place and inform
him of its position. To remove the stoppage he can send forward an empty truck,
the speed of which can be reduced to a minimum as it approaches the disabled
truck by regulating the propelling current, until it strikes against the disabled
vehicle, when full current can be turned on and both trucks forwarded to the
consignee or shunted at the next convenient siding, preferably at one with which
there is telephonic communication so that the subscriber can be asked to transfer
both trucks to the up line and return them to the central coupled together.
The position of trucks may also be indicated to the central station by magneto-
telephones or by microphones placed at intervals in the tunnel, as the noise made
by their passage would be conveyed thither telephonically. In such a case
attendants continually listening at receiving telephones would be required at the
central. Another method would be to cause the trucks to make successive contacts
as they move along which would be registered on a step-by-step dial or other
suitable device at the central. The trucks could likewise be made to indicate
their position by carrying electrical vibrators or reversers which would act electro-
statically on conductors in connection with suitable receivers at the central, or on
condensers or coils of wire placed at intervals along the tracks and connected by
wires to the central.
These indicating devices are applicable to both the down and up tracks, so that
the operators may continuously be advised of the movements of trucks. If the
sections are made seventeen to the mile a pair of expert operators, one for each
track, could keep a constant stream of trucks circulating, as many as seventeen on
the down and seventeen on the up track being possible on a mile line.
Although each subscriber could advantageously be connected telephonically or
telegraphically to the central such a connection is not necessary. Trucks, as
already stated, could be made to announce their own arrival in the subscriber's
stations, and subscribers could place trucks on the up line ready for despatch which
the operator could withdraw when convenient without troubling the subscriber
further. During lulls in the announced traffic or at prescribed intervals during the
day the operator could tap the various sidings along the route and any trucks
ready would at once be brought into the central. As soon as it reached the main
line a truck so withdrawn from a siding would show its presence on the up track by
the operation of one or other of the indicating devices already described.
The subscribers can be supplied with empty vehicles during the night or slack
hours of the day by the operator at the central station without the personal
attendance or attention of the subscriber or his servants. Thus, a subscriber whose

page_text: traffic requires a certain number of trucks every day could find them ready in his
station every morning.
At the central station obstructive catches interlocked with the levers operating
the subscriber's down siding switches may be arranged if desired, so that a truck
placed ready for despatch cannot be sent off until the siding it is destined for has
been placed in connection with the main line. In lieu of picking up propelling
current from a conductor or conductors laid along the tracks, the carriages may
receive motion from voltaic or secondary batteries carried with them.
In the event of two or more central stations being required in the same town,
those two or more stations would be connected with each other by a sufficient
number of tunnels. On the operator at one such central station receiving from a
subscriber parcels which cannot be delivered direct through the medium of the
tunnels diverging from that station, he will in the first case forward them to the
other central station by means of the connecting tunnels.
It is evident that by such means as I have herein indicated a continuous
circulation of parcels can be maintained and deliveries of letters and parcels from
the post office of the town can be effected by connecting the post office to the
parcels exchange system, while parcels or letters or telegrams written out for
despatch by telegraph, together with the money necessary to defray the cost of
forwarding such parcels, letters or telegrams, can be conveyed to the post office
from subscribers' buildings.
In lieu of trucks running on rails trucks suspended from rails or wires as in the
telpherage system may be employed, the details being modified accordingly.
To facilitate inspection and repairs when the tracks are placed one above the
other in the same tunnel, the upper track should not be supported on bridges
stretching across the tunnel but on brackets fastened to the walls of the tunnel and
extending from them only sufficiently far enough to support the rails.
Having now given a general description of my invention and of the mode of
working I shall now for the purpose of setting forth how it may be constructed and
given effect to by electricians and engineers of experience in their several branches,
particularly describe forms which may with advantage be given to each of the
several necessary constituent parts of an electrical parcel exchange system according
to my invention. I desire it to be understood, however, that the details of the
various parts and devices may be considerably varied by competent electricians
and engineers without departing from the essential characteristics of my invention.

page_text: vucy suvu ՄԵ carrieu
Insulated supports
and means taken to ensure good electrical connection between the various lengths.
When space is an object and for the general convenience of working in any case
the down and up tracks may be contained in one tunnel fixed one above the other
on brackets bolted or rivetted to the walls of the tunnel as shown in Figure 1
at R R and R2 R². In the intervals of traffic this plan leaves the whole height
of the tunnel available for workmen besides facilitating the formation and working
of sidings.
VEHICLES.
The trucks may run on four or more wheels and each may carry an electro-motor
with its collectors and necessary appurtenances or be attached to separate motor
trucks. To obtain the maximum carrying capacity the wheels may be attached to
the ends of the truck body and to facilitate the passage of curves the wheels should
be given side-play. Electro-motors of many different designs may be adapted to
the purpose of propelling the trucks. An Immisch motor of small size fitted with
carbon brusbes and similar to the Immisch motors used for electric launches in
which the direction of rotation is reversed by changing the direction of the current
in the armature coils, is a suitable motor to employ.
The manner of gearing the motor to the driving wheels may also be greatly
varied and any of the usual methods, including spur, friction, belt and chain
gearing, will suffice. As the electro-motor obtains its propelling current from a
conductor communicating with the source of power at the generating station, and
which runs parallel to the track it must be provided with suitable contacts or
collectors, which by brushing, rubbing or rolling on the parallel conductor as the
truck moves along preserves a constant circuit through the motor coils.
The design
of these contacts or collectors may be greatly varied many efficient kinds being
known to electricians. In an electrical parcel exchange system the prevention of
collisions between trucks travelling in opposite directions is a necessity and it is
most important to put it out of the power of those operating the system to cause
such collisions by mistake or otherwise. According to my invention this may be
done by placing the parallel conductor in such a position and so arranging the
collectors on the trucks that a truck will not obtain propelling current if placed
wrongfully on either the up or down line, or will only obtain such current as will
move it in the same direction as other trucks travelling on the same track. I
effect this object by fixing the parallel conductor between the two tracks and
providing each truck with two collectors. When one track is placed above the
other, one collector which projects above the truck is designed to make contact
only when a truck is below the parallel conductor and the other which projects
below the truck only when the truck is above the conductor. The collectors are so
arranged that current obtained from the top collector will always move the truck
away from the central station and current obtained through the bottom collector
will only move it towards the central station so it is obvious that vehicles can never
be made to travel in the wrong direction. The details of such a vehicle are shown
in Figure 2, in which M is the motor, C¹ the top collector and C2 the bottom
collector. The direction of the current through the armature coils and the coils
which excite the field magnets, and consequently the direction of rotation, is deter-
mined before the commencement of a journey by the sender setting a switch on
the vehicle which brings the proper collector for the journey into play.
The con-
nections of such a switch are shown in Figure 3, in which L' L' are metal levers
insulated from each other by the insulating yoke Y; P1 P2 P3 three contacts
touched by the levers when turned to the left or right. When, as in the figure,
the levers are placed straight so as not to touch any contacts the motor
ceases to operate; C1 C2 wires leading from the top and bottom collectors

page_text: •
and M¹ M² and F1 F2 wires leading respectively to the motor armature and field
magnets. The connection marked E indicates the path of the propelling current
returning to the generator after traversing the motor coils and field magnets.
This return path may be one or both rails insulated or uninsulated; the metal
of which the tunnel is built or a special return conductor which may or may
not be insulated. When the rails are employed the current may reach them
through the body of the vehicle and the axles and wheels, flexible brushes or
contacts bearing on the axles to ensure proper connection.
In the other cases
a special contact must be fitted to each motor truck which brushes, rubs
or rolls on the metal of the tunnel or on the special return conductor as the
train runs along. Instead of separate top and bottom collectors being used one
collector reversible in position at the will of the sender may be employed.
Such a reversible collector, consisting of an arm C pivotted at A and working
between two semi-circular cheeks or guides, is shown in Figure 4, its two
positions being indicated by C¹ C². When set it is retained in its position by
a pin at P1 P2 passing through the arm and both guides, or by other suitable
means. A similar switch to that shown in Figure 3 must be employed, separately
or combined with the collector in such a way that the setting of one necessarily
moves the other into the required position. Figure shows a section of the tunnel,
with one track above the other, through which trucks are passing in opposite
directions. In this case two return parallel conductors E1 E2 are shown, one at the
top, the other at the bottom of the tunnel. With this plan the switch shown in
Figure 3 may be dispensed with as the necessary reversal of current direction
through the armature coils is obtained automatically by the act of placing the
truck on the upper or lower track. When on the upper track the current enters
the motor M through the main parallel conductor PC and lower collector C² and
leaves by the upper collector C₁ and return parallel conductor E'; when on the
lower track the current traverses the motor in the reverse direction, entering by PC
and C and leaving by C² and E². But a switch will still be required to regulate
the current direction through the field magnet coils.
PARALLEL CONDUCTORS.
These may be of copper, iron or other suitable metal and either continuous
throughout or divided into insulated sections supplied with current by feeding wires
from the generator station. They may be advantageously carried by the brackets
which support the rails, or otherwise, by special brackets attached to the tunnel.
In all cases they must be carefully insulated by the interposition of blocks of
vulcanised fibre or other suitable insulator when used for the main or out circuit
from the central; when used for returns they need not be insulated. The main
parallel conductors are shown at PC and the return conductors at E¹ E² in
Figures 1 and 5.
SWITCHES OF SUBSCRIBERS' DOWN SIDINGS.
These resemble railway crossing switches or cross-over points in general design.
Normally a subscriber's down siding switch is held closed by springs, weights,
permanent magnetism, electro-magnetism or any other suitable force, so that the
continuity of the main line is maintained, and is opened so as to put the siding in
connection with the main line by means of a current sent from the central station
which has the effect while it lasts of overcoming the pull of the force tending to
keep the switch closed. Figures 6 and 6^ show one sufficient method of accom-
plishing this, the points P1 P2 which are normally held firm in the direction
indicated by the arrow by the spring S are pulled over as soon as a current from
the central circulates in the solenoid electro-magnet E M, which is fixed between
the rails R R or any other suitable position, the solenoid Q which is attached to P¹
being sucked into the electro-magnetic coil.
When the attraction due to the current ceases the spring S reasserts itself and

page_text: closes the switch. Instead of a solenoid, electro-magnetic devices of many different
designs may be employed. The process may be reversed by causing a current to
circulate normally in the electro-imagnetic coils, and so holding the switch closed
by attraction against the pull of a spring or weight. The switch is then opened
by interrupting the current and allowing the spring or weight to pull the points
By using polarised electro-magnets all springs, weights or their equivalents
may be dispensed with, for in this case the switch can be held in its normal
position by magnetism of one polarity and opened by that of the other the
polarities being neutralised or reversed by currents of one or the other sign from.
the central.
over.
SIGNALLING TO THE CENTRAL STATION OF THE ARRIVAL OF A TRAIN
ON A DOWN SIDING.
It is desirable that the operator at the central should have actual evidence of the
safe arrival of a train in a siding. This I accomplish by carrying the wire in
connection with the siding switch to a point along the siding fully equal to the
length of the longest train that can ever be sent into it and there fixing a contact
which is momentarily broken by being touched or struck by a projection with
which every truck is furnished. Such a device is shown in Figure 7 where T¹
to T indicate spring contacts resembling in general character a telephonic spring-
jack interposed in the return wire proper to the siding of the conductor operating
the electro-magnetic siding switches, which contacts are separated by the passage
At the central an
between them of an insulating arm projecting from the truck.
indicating device which is inoperative so long as a current flows in the wire is
actuated by the cessation of the current consequent on the passage of the insulating
arm and informs the operator that the train in the siding and that the switch
may be closed for main line traffic. When a train contains several trucks the
spring contacts will act as the insulating arm carried by each truck passes, but by
using insulating arms that can be set or folded back by the sender so as to pass the
contacts without touching it can readily be arranged for the last truck alone to
break the contacts by setting the insulating arm of that truck only to touch the
contacts in passing. The indicating device at the central station may vary greatly.
It may be an electro-magnet the armature of which is kept attracted during the
circulation of the current in the siding switch wire and when released by the.
temporary interruption of the current drops a shutter, strikes a gong or closes a
local circuit through the coils of an electric bell or other suitable instrument.
The details of the contacts, the insulating projection from the truck as also the
position of the contacts in respect to the rails and the truck may be greatly
varied.
BLOCKING OF SUBSCRIBERS' DOWN SIDINGS.
After a truck or train has entered a siding it is desirable to mechanically
block the siding especially if it is on a rising grade, so that a train may not
through any accident run back and foul the main line. This may be accomplished
by making one or more lengths of one or both rails movable in an upward direction
under the influence of a spring or springs placed below them in such a manner that
each movable length of rail is pivotted at the end which is nearer the main line
and free to move upward at the other. The springs are so adjusted as to be
compressed as soon as the wheels of a truck coming from the main line enter upon
the movable rail, which is forced down and completes the continuity of the track.
As soon as the last pair of wheels has passed the moveable rail rises and presents.
a buffer or stop-block to any vehicle running back towards the main line. This
device is shown in Figure in which R R2 are the fixed rails; M the movable
length pivotted at P and forced upwards by the spiral spring S. When depressed
by the weight of a passing truck, M sinks to a level with R2 and so completes the
track. Instead of making sections of the actual rails perform this duty separate-

page_text: muy reauny be made to replace or supplement the
spring contacts, shown at T in Figure 7, used for the purpose of signalling to the
central station the arrival of a truck on a down siding. In such a case the movable
section would be insulated from the other rails and its upward movement restricted
by a stop contact.
The circuit of the siding switch wire being completed through the movable
section and the stop contact, would be broken by the passage of a truck.
Or the
device shown in Figure 8 may be employed, in which C₁ C' are two spring contacts
which are forced apart by the descent of the insulating arm T.
SUBSCRIBERS' STATIONS.
After entering on a siding the train proceeds until it reaches the subscribers'
station which the siding serves. The parallel conductor serving the down trains is
preferably, when the circumstances will admit, stopped short some distance within
the tunnel, or when the two tracks are one above the other the surface of the
parallel conductor from which the down motors obtain current may be covered with
insulating material so that the train loses power as it approaches the station and
finishes its journey by the momentum it has acquired. When the siding enters
the station on a rising grade it may, however, be necessary to continue the parallel
conductor beyond the outlet of the tunnel. On emerging from the tunnel the train
passes over movable sections of rails similar to that employed for blocking
subscribers' down sidings and drawn in Figure 8, which movable sections not only help
to bring the train to a stand but by rising automatically behind the wheels prevent
any running back into the tunnel and make it difficult for any mischievous or careless
person to endeavour to forward a train on the wrong track. To bring the train to
a complete stand the device shown in Figure 9 may be used. It consists of a
hook H so placed between the rails that it engages with the first axle or other
suitable part of an incoming truck. The hook being attached to a cord or chain
working over a pulley P and arranged to lift a weight W, or to extend a spring,
the motion is arrested gradually or quickly according to the resistance of the
weight or spring and the length of the cord. The track behind the train being
blocked by the rising of the movable rails the weight or spring cannot force it back
into the tunnel. The end of the track may be guarded by stop-blocks or elastic
buffers. The arrival of a train in the station may be signalled electrically to any
part of the premises or even back to the central station by aid of contact-makers
or -breakers on, or operated by, the elastic buffer or the movable sections of rail,
or by means of ordinary contacts worked by the train. Figure 10 shows one mode
of doing this by aid of the movable rail M which has a metallic projection T.
insulated from the rest of the rail. As the projection descends it completes a
connection between the springs C1 C2 which are normally apart and which are in
circuit with the voltaic battery V and the electric bell B which may be in any part
of the building. If the wire W in Figure 7 be taken into the subscribers' station
before being led back to the central the operation of the contacts T shown in the
same figure, which are intended to inform the central station that a train has
entered a siding, may be made to convey the same information to the subscriber
who will thus have automatic notice of the approach of a train. When a train has
been unloaded it must be transferred to the up track in order to be returned to the
central. This transfer should, if practicable, be effected without lifting the trucks
clear of the rails. It is therefore preferable when station space will admit to cause
the two tracks to diverge after leaving the tunnel until they meet on a level and
become one as shown in Figure 11. The transfer is effected by means of an ordinary
catch switch set for the up track and opened automatically by the wheels of a truck
arriving on the down line. Or the two tracks may be continued one above the other
to the end and terminate in a two-storied vertically movable platform which can be

page_text: depressed or raised by means of the hand, pulleys, weights or any power suitable
for working lifts. If the lower of the two tracks is used as the down line the
platform in its normal position would have its upper storey on a level with the
bottom track. When an arriving train runs on to the platform the latter is raised
until its upper storey is on a level with the upper track and its lower storey rises to
the level of and makes good the lower track. If the upper track is used as the
down line the process is reversed, the platform being depressed instead of raised.
In this case also an arriving train may be transferred immediately and automatically
to the up or lower track by means of a one-storied platform normally kept on a
level with the upper track by means of weights suspended over pulleys, by pistons
working in air or water tubes or by other suitable device. The weight of the train
overcomes the resistance of the weights or pistons and the platform sinks until it
reaches the level of the lower or up track. Upon the train being transferred to
this track, an operation which may be managed by gravity by giving the platform
an inclined position when at rest on its bottom stops, the platform rises again and
makes good the upper or down track.
The platform should be provided with projections or other adequate devices so
as to block the down track as soon as it sinks away from its level. One obvious
method of doing this is by providing a bar, shutter or curtain attached to the
platform at its junction with the down track and at a height only just sufficient to
allow an arriving train to pass under it. As soon as the platform sinks, this bar,
shutter or curtain will also descend and so prevent a second arriving train from
passing the point of junction between the down track and the platform. In order
that the platform may not begin to sink before the whole of an arriving train is on
it it is provided at its further extremity with an arm, trigger or catch pivotted at
its centre and one end of which is kept by means of a spring constantly pressing
against the smooth face of an upright bar or pillar which may be a part of the
framework in which the platform works, and is placed at that end of the platform
most distant from the main line.
When the platform is on a level with the upper or down track the end so kept
pressing falls into a notch in the bar or pillar and so locks the platform at that
level. When an arriving train runs on to the platform and the leading end or
buffer of the first truck has reached the further extremity it strikes the free end of
the trigger or catch, jerks the other end out of the notch, and so unlocks the
platform which thereupon sinks under the weight of the train.
To prevent
rebounding from the platform a blocking device such as is drawn in Figure 8 may
be used at the main line end of the platform. A similar locking device can be
used, if desired, to keep the platform on a level with the lower or up track until
the train is clear. Automatic working at subscribers' stations may be extended by
the use of specially constructed trucks carrying their load in receptacles which can
be tilted, until the contents are thrown out, by encountering suitably designed arms
or projections on arriving in a station. The emptied vehicles then gain the up
track by means of the device shown in Figure 11 or by the automatically sinking
platform, when the collector used on up journeys encounters the parallel conductor,
obtains current therefrom and returns to the central station without receiving any
attendance at the subscriber's station. In this kind of working is necessary that
the switch which determines the direction of the current through the motor be
changed automatically between the time that the down collector leaves the parallel
conductor on the down journey, and the up collector encounters it on commencing
the up journey. If the handle of the switch is furnished with a projection designed
to engage with a suitable catch or arm fixed at a proper point within the station
the passage of the truck past this catch or arm will effect the necessary change.
Or the switch may be reversed by the tilting of the upper portion of the vehicle
for unloading purposes. When the system is non-automatic the forwarding of an
up train is managed by an attendant at the subscriber's station. In up-train
working it is necessary that an attendant shall not have the power to forward a
train from his station without the consent of the central operator. Figure 12 shows
C

page_text: the means by which this is rendered impossible. At the entrance of the tunnel on
the up track is placed a movable section of rail insulated from the other rails,
generally similar to those already described in connection with the down sidings
and stations but furnished with a solenoid armature Q which is sucked into the coil
of the electro-magnet E M when a current from the central circulates through the
said electro-magnet.
Normally the movable rail M is kept up by a spring S or a counter-weight so
that its bent extremity T blocks the line against the vehicle V which cannot be
pushed past the obstruction thus created. P C and P C are sections of the parallel
conductor which are disconnected from each other electrically when M is raised in
its normal position, so that the collector C of the truck V, although pressing
against P C obtains no current therefrom. When the operator at the central is
ready to admit V to the main line he sends a current by the wires W' W² through
the electro-magnet E M, which pulls M down to the level of the permanent
rails R R2 and at the same time puts P C¹ and P C in electrical connection as the
metallic arm T in descending joins the springs C1 C2, which are normally apart, in
electrical contact. The collector C then obtains current from P C and V imme-
diately enters the tunnel on its up journey. The sender has consequently nothing
to do but place the vehicle V on the up track with its collector C against P C² the
central operator doing all the rest. The solenoid electro-magnet may of course be
replaced by others of different constructions and the details of the whole device
may be considerably modified without altering the nature of my invention.
ARRANGEMENT OF WIRES GIVING ELECTRICAL CONTROL OF DOWN
SIDINGS.
The arrangement which I prefer is shown in Figure 7 where W is an insulated
wire which after being connected at the central station to a source of electricity B,
such as a dynamo or a primary or secondary battery, is led through the tunnel as
far as the last siding. At each such siding an insulated branch wire, such as W
in the figure, is taken off W and after passing through the electro-magnet E M
controlling the switch of siding No. 4 and the signalling contacts T is led back to
the central where after passing through the coils of the indicating device S it is
connected to the circuit-closer L. Other branch return wires are indicated
at WW2 W3 and other electro-magnets, signalling contacts, indicating devices
and circuit-closers are shown respectively at E ME M² E M³; T' T' T³; S¹ S² S³ ;
and L L L³.
In the position of the circuit-closer shown at L' no current can circulate
through EM, T, W₁ or S₁ consequently the switch of siding No. 4 will remain
closed and right for main line traffic. But should the operator close the circuit-
closer L a current immediately circulates and the switch of siding No. 4 will be
opened. The indicator S', which may be in the form of a semaphore, as drawn in
Figure 7, the arm of which is pivotted ard kept normally horizontal by a counter-
weight formed by the armature Q of a solenoid electro-magnet E M which is
sucked upwards when a current circulates, thereby causing the arm to drop, will
show the operator that the circuit is complete. This position is shown in Figure 7
at S² and L² in connection with siding No. 2. A train sent from the central will
therefore enter this siding on reaching it since its switch should be open. The
effect of the train separating the contacts T2 as it passes is to make the arm of the
ndicator momentarily rise thus notifying the operator if he is watching that the
train is safe in the siding. But as the operator cannot always be trusted to watch
it is desirable to make the semaphore arm or some other part of the indicator
mechanism on the cessation of the current close a local circuit in which an electric
bell, drop shutter, or other suitable device is included. On receiving such a signal
the operator opens the circuit-closer L² thereby closing the switch of siding No 2.
The dropping of the indicator arm only shows that the necessary electrical circuit
is complete and not that the siding switch has been actually opened, which indeed

page_text: may be prevented by mechanical impediments. It is easy to signal the actual
opening of the switch by means of an independent branch return wire the circuit of
which is closed through contacts operated through the tongue of the switch itself
after it has arrived at its open position. Such an independent branch wire and
indicator is shown by dots in Figure 7 in connection with siding No. 2.
The contacts worked by the switch tongue are indicated by Z. With the same
arrangement of conductors the mode of working may be reversed, that is to say,
the nominal positions of the siding switches and indicators may be maintained by
the circulation of a constant current through them, the circuit-closers being
normally closed, and the switches opened by interrupting the current. The
signalling contacts T would, however, not operate with such a plan unless made to
establish instead of interrupt a current.
ARRANGEMENT OF WIRES GIVING ELECTRICAL CONTROL OF
BLOCKS AT SUBSCRIBERS' STATIONS.
THE UP-LINE
The arrangement which I prefer for this purpose is precisely similar to that
already described for giving control of the down sidings, that is to say a main wire
connected to a source of electricity at the central station is led along the tunnel as
far as the most distant siding. A branch from this main wire is led along each
siding as far as the station, then through the coils of the electro-magnet controlling
the block, back along the siding to the main tunnel and thence to the central, where
it is connected through an indicator and contact-closer resembling those shown at S
and L in Figure 7. So long as the contact-closer remains open no current
circulates and the stop remains up and blocks the up track. When closed the
movable block is attracted to the level of the permanent rails and, connecting the
two sections of the parallel conductor, so transmits current to the motor of
the vehicle. The indicator shows the operator that the circuit has been completed
and special contacts like those shown at Z in Figure 7 may also be employed to
inform him that the movable block has actually been attracted to the level of the
permanent rails, these contacts being operated by the movable stop itself on
reaching its position of maximum depression. Contact-breakers like those shown
at T in Figure 7 may likewise be used to signal the actual entry of the train upon
the up siding. By counting the signals given by the successive breaks in the
circuit the operator can inform himself of the number of vehicles of which the train
just started is composed. If he has already been informed by telephone or
otherwise of the number proposed to be sent he can by counting the signals assure
himself that they have all actually started. By taking E M as representing the
block electro-magnets, Figure 7 represents the general arrangement of the up line
block circuits. As with the system controlling the down siding switches the mode
of working may be reversed, using a constant current to maintain the normal
position of the apparatus and interruptions thereof to produce the necessary
deflections. The constant current method has an advantage inasmuch as any
accidental interruption of the circuits at any point is at once notified to the central
station by the indicator arm falling without the corresponding circuit-closer being
opened.
AUTOMATICALLY INDICATING THE PROGRESS OF TRAINS.
This is effected by means of the rails themselves which are carried on insulated
supports of vulcanised fibre, porcelain or other suitable insulator for the purpose.
The connections for both the down and up tracks are the same and are shown in
Figure 13. One rail of each track R, forms a continuous conductor the whole
length of the line, special care being taken to ensure good contact between the
lengths of rails by bridging the joints with wire soldered to pins let into the rails;
by running a small wire alongside the rails and connected to each rail, or by some
other sufficient method. At the central station the continuous conductors so formed
are connected to one pole of a source of electricity B. The remaining rail of each

page_text: track is also insulated from the earth but is divided into sections which have no
electrical connection with each other, being separated at the desired points by small
air gaps or by the interposition of some suitable insulating material as vulcanised
fibre. The sections may be of any required length, but 110 yards or one-sixteenth
of a mile is a suitable one. Each such section has an insulated wire attached to it,
marked W to W in Figure 13, which wire is led back to the central where after
passing through the coils of an electro-magnetic indicator, as S¹ to S³ in Figure 13,
it is connected to the other pole of the source of electricity. The indicators may be
in the form of semaphores, as before, with the difference that the arms are horizontal
when a current is circulating and sloping when the circuit is broken. As before,
the sloping position may be maintained by the weight of the armature Q of a
solenoid electro-magnet E M in Figure 134, and the horizontal by the sucking of
the said armature into the coil. A set of return wires W' to W' and indicators S¹
to S is appropriated to each track and the progress of a train out or home is made
apparent by the behaviour of the semaphores. When a truck is on the line it
establishes electrical contact between the two rails of the track, either through its
wheels and axles or through special brushes which rub or roll on the rails as the
vehicle moves along and so causes a current to circulate successively in each of the
return wires W' to W and the armatures of each of the indicators S¹ to S to be
attracted one after the other. In Figure 13 a truck is shown traversing the third
section from the central causing a current to circulate and the armature of S³ to be
attracted and its arm lowered to danger.
CENTRAL STATION.
The arrangements for the receipt of arriving trains resemble those already
described for subscribers' stations, similar devices for bringing incoming trains to a
stand, preventing running back and changing from one track to another being
provided. The electrically-controlled block for preventing the premature departure
of trains may be dispensed with, but a similar block worked mechanically by the
operator may be used with advantage. The removal of this block should convey
current in a similar manner to that shown in Figure 12 to a hitherto insulated
section of the parallel conductor within the central station against which the
collectors of the trains ready for departure are placed. The system is designed to
work at a constant potential and the operators control the speed of trains by means
of switches which interpose more or less resistance in the parallel conductor circuits
by methods which are well understood by electricians.
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 1
claim is :-
1. An electrical parcel exchange system with its several modifications and
alternatives substantially as described.
2. Substantially as described the various parts, appliances and devices necessary
to the working of an electrical parcel exchange, including the combination for, and
application to, the said purpose, substantially in the manners set forth, of wires,
conductors, electro-magnets, electro-motors, collectors, contact-breakers, contact-
makers, switches, blocking apparatus, alarms and the other accessories herein before
enumerated.
L
1
C
1000
A. R. BENNETT.