FIELD OF THE INVENTION
This invention relates to a rail transport bogie and a rail transportation system.
BACKGROUND TO THE INVENTION
Conventional transportation systems utilise several means to move goods and people. These
include conventional rail transport systems that are typically powered by one or more
locomotives that pull, or push, interconnected railcars. Locomotives typically have to be
heavy enough to get sufficient traction on the rail track in order for it to accelerate the weight
of the entire train from standstill to a specified speed, pull it up inclines and to decelerate the
train from speed down to standstill again.
This is problematic due to the high relative weight of the locomotives to the overall weight of
the load. To get traction, a train has to be heavy or extra motors have to be added to each
and every rail cart being pulled by the locomotive or locomotives. This increases the cost and
complexity of the train. The heavier the train itself has to be to get traction, the less efficient
it is because weight is being carried around unnecessarily. For example, a train with freight
cars dedicated to the movement of ore from a mine to a processing plant will typically be
laden in one direction and empty in the opposite direction. The unnecessary weight is now
being carried twice the distance.
Of course it would be easier to obtain better traction if trains used wheels made from a
material with a higher friction coefficient with respect to steel rails, for example rubber or
polymers. However, such wheels will not have the durability required for rail transport. Such
wheels would wear much faster than steel wheels and may fail under compression of the
loads they have to support (in circumstances where steel wheels do not fail). Trains often
have to transport heavy loads over very long distances and it will be extremely disruptive if a
train has to have a wheel changed along the way. Considering that a train cannot simply pull
over to change a wheel like a truck can do, it becomes clear why trains are forced to use
wheels made from highly durable and reliable material, such as steel.
When moving people or goods in high volumes using conventional public transport systems
and bulk good transport systems such as busses, trucks, and trains three major problems
are experienced:
1. Conventional systems include batch-based systems. This means a batch of people or
goods are moved between two points. This is less efficient than a continuous
movement system, because people and goods have to wait before they can be
grouped into a batch that is moved, and if the batch is completed then the people or
goods have to wait for the next batch to be filled before they can be moved. Typically,
for example with people transport, in peak times there is not enough capacity to move
the batches fast enough, resulting in long waiting periods. In off-peak times, bulk
transport system operators typically downscale the number of batches per time unit
thus reducing the active capacity of the system, also resulting in long waiting periods.
2. Conventional systems also include movement in accordance with a predetermined
schedule, and not on demand. This results in batches often not being filled and the
vehicles often having to transit well below their optimum load capacity, and on other
times for there to be a higher demand than the number of batches scheduled can
accommodate, again leading to sub-optimum movement.
3. Conventional systems moving in accordance to a schedule often do not run from a
starting point straight to a destination point, but rather from a starting point to and end
point while stopping at various points, such as stations, in between. This increases
travel time and also results in sub-optimum utilization of transport capacity.
Conventional logic dictates that the solution to these problems is to move larger volumes of
people and goods together in order to improve economies of scale, and then to optimise the
scheduling of the vehicles so that the movement of empty or half full vehicles are minimised,
and then to limit the number of stops the vehicle makes along the scheduled route so that
overall time is saved where possible. A train operator hitching more railcars during peak
hours to the same locomotive provides evidence of this. It is also evidenced, in trucks
carrying greater numbers of containers each. In trains handling raw materials such as ore, it
is not uncommon to observe trains having a length of several hundreds of meters, even in
excess of a kilometre, and for that ore transportation track to then only have a single starting
point and a single destination point. This is also replicated in, for example, the road trains of
the Australian outback.
A problem with this approach is that due to the sheer bulk the drive unit for such high
capacity transport unit has to be increased. This comes at an increased cost and strain on
the equipment. Due to the sheer weight and inertia of the system, it takes longer to
accelerate and decelerate, which actually increases the actual travel time of the unit. In
addition, if the unit suffers a malfunction then a larger volume of people or bulk material is
delayed whilst the problem is sorted out.
It is proposed by the applicant that people and bulk goods may be transported much more
efficiently in small transportation units, and for the transportation system as a whole to have
the ability to allow individual transportation units to move independently, or in small groups,
from any station along the transportation network to any other station without having to stop
at stations in between this departing station and the specific destination station. This is
particularly true if the movements are provided on demand rather than according to a
predetermined schedule, and when the units are moved in an automated manner as
opposed to requiring a driver.
It is believed, as an example, that it would be highly efficient for commuters to be transported
in small transportation units catering for as few as 6 people or less at a time, from any
position on a pre-established transportation network, for example a grid of intersecting
tracks, to any other selected position on this network on demand when those people want to
be moved from the one position to the other, without them having to abide by a schedule or
having to waste transit time by having to stop at other positions along the network in between
their departing and destination positions.
In such an instance it is recognized that it would be necessary for the individual
transportation units to be able to, in traveling from one location to another, switch safely and
at reasonable speed from one track to another in the grid.
The same should apply to the transport of goods between positions on the grid.
OBJECT OF THE INVENTION
It is an object of the invention to provide a rail transport bogie, a rail transport system and a
track for such a bogie and transport system, which at least partly overcome the
abovementioned problems.
SUMMARY OF THE INVENTION
In accordance with this invention there is provided a rail transport bogie configured to
operate on a track having track surfaces on opposite sides thereof and a slot through the
track extending along substantially the centre of the track, the bogie comprising a loadbearing
wheel to run on a first of the two track surfaces, a support shaft extending from the
load-bearing wheel operatively through the slot in the track and terminating in load support
means, a first pinch wheel rotatably secured in a forward position in respect of the support
shaft and a second pinch wheel rotatably secured in rearward position in respect of the
support shaft, with both the first and second pinch wheels located between the load-bearing
wheel and load support means to run on the second of the two track surfaces, the loadbearing
wheel and pinch wheels clamping between them the bogie to the opposing track
surfaces, and at least one of the load-bearing wheel and either or both of the pinch wheels
connected to a motor operatively to be driven thereby to comprise a driven wheel for the
bogie.
There is further provided for movement of the bogie in a forward or rearward direction to be
effected by forward or rearward driving of the driven wheel.
There is further provided for the bogie to be configured, upon acceleration thereof as a result
of rotation of the driven wheel, for inertia of a load operatively secured to the load support
means to pivot the bogie on the axis of the load-bearing wheel to force the pinch wheel
located in the then rearward position relative to the direction of movement of the bogie
against the second of the track surfaces, operatively increasing the clamping force between
the load-bearing wheel and the rearward pinch wheel to increase friction between the loadbearing
wheel and first of the two track surfaces to assist with acceleration of the bogie and
the load secured to it.
There is also provided for the bogie to be configured, upon deceleration thereof as a result of
braking of any of the wheels of the bogie, for inertia of a load operatively secured to the load
support means to pivot the bogie on the axis of the load-bearing wheel to force the pinch
wheel located in the then forward position relative to the direction of movement of the bogie
against the second of the track surfaces, operatively increasing the clamping force between
the load-bearing wheel and the forward pinch wheel to increase friction between the loadbearing
wheel and first of the two track surfaces to assist with deceleration of the bogie and
load secured to it, either to reduce its speed or bring it to rest.
There is further provided for the bogie to be configured, upon reaching a steady speed at
which the force required to maintain the forward speed of the bogie is lower than the force
required to accelerate the bogie from rest, for the rearward pinch wheel to be forced with a
lesser force, or not to be forced at all, against the second of the track surfaces and
respectively for the clamping force to be commensurately lower compared to when the bogie
is accelerated from rest or for the clamping force to be zero, operatively allowing the bogie to
move with a lower clamping force between the load-bearing wheel and the then rearward
pinch wheel at steady speed than at acceleration of the bogie.
There is further provided for the driven wheel to comprise a set of two axially aligned,
preferably axially connected, driven wheels, with the driven wheels configured such that they
both run on either the first or the second of the two track surfaces on opposing sides of the
slot in the track.
There is still further provided for each pinch wheel to comprise a set of two axially aligned,
preferably axially connected, pinch wheels, with each pinch wheel set configured such that in
each set the two pinch wheels run on the second of the two track surfaces on opposing sides
of the slot in the track.
There is further provided for a pinch wheel bracket to be secured to the load support shaft
and for the bracket to extend to two opposing ends, a first end to a forward position in
respect of the support shaft and second end to a rearward position in respect of the support
shaft, and for the first pinch wheel to be rotatably secured to the first end, and for the second
pinch wheel to be rotatably secured to the second end of the pinch wheel bracket.
There is still further provided for the load-bearing wheel to comprise the driven wheel.
There is further provided for the ratio of the distance between the axis of the rearward pinch
wheel and the attachment of the pinch wheel bracket to the load support shaft to the distance
between the axis of the attachment of the pinch wheel bracket and the load support means to
be variable depending upon how much friction is required between the driven wheels and the
two track surfaces to create the optimum amount of traction that is required for any specific
set of circumstances, the ratio preferably being between 1:2 and 1:5, and most preferably to
be about 1:3 where the bogie is predominantly operated horizontally.
There is further provided for the ratio of the distance between the axis of the rearward pinch
wheel and the attachment of the pinch wheel bracket to the load support shaft to the distance
between the attachment of the pinch wheel bracket and the load support means to be at
least 1:5, where the bogie is operated, at least on part of a track, at steep angles.
There is still further provided for the load-bearing wheel and the pinch wheels to have
resiliently compressible running surfaces, preferably comprised of rubber or plastics material,
alternatively for the load-bearing wheel and the pinch wheels to have substantially
incompressible running surfaces, preferably comprised of metal, further preferably steel.
There is further provided for the motor to comprise a linear motor or a rotary motor, and
preferably for a linear motor reaction plate or reaction plates forming part of the linear motor
to be secured to the load support shaft, preferably above the pinch wheel bracket, and
alternatively for the rotary motor to be secured to the load support shaft, preferably below the
pinch wheels.
According to a further feature of the invention there is provided for the bogie to include
guidance means operable at each track intersection to move the bogie laterally across the
track towards one side of the track or another, depending on which track the bogie is to
follow leading from the track intersection, the guidance means comprising at least one guide
wheel being movable between a neutral position and a guiding position, with the guide wheel
configured in its guiding position to interact with a guide member that extends along a track
leading from a track intersection to cause the bogie to follow such track, and the guide wheel
configured to not interact with any guide member when it is located in its neutral position.
According to a yet further feature of the invention there is provided for the bogie to include
guidance means operable at each track intersection to move the bogie laterally across the
track towards one side of the track or another, depending on which track the bogie is to
follow leading from the track intersection, the guidance means comprising at least two guide
wheels located on opposing sides of a longitudinal axis of the bogie and being movable
between a neutral position and a guiding position, with each guide wheel configured in its
guiding position to interact with a guide member on its side of the longitudinal axis of the
bogie that extends along a track leading from a track intersection to cause the bogie to follow
such track, and the guide wheels configured to not interact with a guide member when they
are located in their neutral positions.
There is further provided for the two guide wheels to be connected and configured such that
both guide wheels cannot simultaneously be in their respective guiding positions.
There is also provided for the bogie to include an electrical contact configured complimentary
to an electrical rail associated with the track operatively to electrically connect the bogie with
the rail, preferably for the electrical contact to extend from above and to the side of the driven
wheel, and further preferably for the contact to be electrically connected and configured to
charge the battery or power the motor.
There is still further provided for the bogie to include drive control means secured to the load
support shaft proximate the motor, preferably on an opposing side of the load support shaft
relative to the motor.
There is further provided for the motor and the driven wheel to be rotatably secured by
means of a drive belt or drive shaft, preferably a chain extending around sprockets on each
of a motor drive shaft and the axis of the driven wheel, alternatively when a chain is not best
suited for the bogie to include a secondary drive shaft that is connected from the motor drive
shaft to the axis of the driven wheel using a coupling, preferably a differential coupling.
In an alternative configuration there is provided for the motor to be connected to the driven
wheel via a sprocket secured to a secondary axis proximate the axis of the driven wheel, with
the secondary axis and the axis of the driven wheel being rotatably secured to each other by
meshed gears having a predetermined gear ratio.
There is further provided for the load support means to comprise a load bearing secured to
the end of the load support shaft, and preferably for the load to be securable to the load
bearing enabling the load to be suspended from the bogie, pulled behind the bogie or pushed
in front of the bogie.
There is still further provided for the bogie to include a frame secured proximate the load
support shaft end, for the frame to extend to two opposing ends, a first end to a forward
position in respect of the support shaft and second end to a rearward position in respect of
the support shaft, and for each end to extend into an arm directed towards the pinch wheel
on its side of the load support shaft, with each arm carrying a battery.
There is further provided for each arm to terminate in at least one directional control wheel
operatively running on the sides of the slot in the track, and preferably for each arm to
terminate in a set of spaced apart directional control wheels operatively running on opposing
sides of the slot between the opposing track surfaces, the running surfaces of the directional
control wheels spaced apart by a distance complimentary to the width of the slot.
According to a further feature of the invention there is provided a rail transportation system
comprising a network of tracks, a plurality of bogies as defined above each of which has a
driven wheel arranged to run on and be supported by the track and which are capable of
supporting, pulling or pushing a load secured to the bogie, each bogie being driven along the
track and including guidance means which allows it to switch from a track leading to a track
intersection to a preselected track leaving the track intersection without any load-bearing
wheel of the bogie being unsupported by the track.
There is further provided for at least some of the tracks to meet one another at track
intersections, for the system to include guidance means which allows each bogie to switch
from a track leading to a track intersection to a preselected track leaving the track
intersection without any driven wheel of the bogie being unsupported by the track.
There is further provided for the track intersection to include no moving parts to enable bogie
switching.
There is further provided for the guidance means to comprise a rib that extends along each
track leading from a track intersection, the rib being shaped and configured to direct a raised
guide wheel on its side of the bogie to its operative outside.
There is still further provided for the track to comprise an elongate set of races spaced apart
by an elongate slot with the set of races kept in spatial relation to each other by means of a
frame extending from the sides of the races, the load support shaft of the bogie operatively
extending through the elongate slot.
The invention also provides for the track to include an electrical rail extending at least for part
of the length of the track above the first of the two track surfaces complimentary shaped and
configured to the electrical contact of the bogie to allow the bogie electrical contact
operatively to contact the rail.
According to a yet further feature of the invention there is provided a track for the rail
transportation system defined above, the track being modular, the modules including straight
sections and curved sections, and for each module to include a set of races spaced apart by
an elongate slot through the track operatively allowing the load support shaft of a bogie to
extend through the slot, with the set of races kept in spatial relation to each other by means
of a frame extending across the track, preferably from the sides of the races, with each race
being provided with a wear resistant lining removably secured to its top, bottom and side
facing the slot.
There is further provided for the frame to include a brace proximate the end of each module
with each brace having a set of spaced apart legs each of which is secured to a side of the
track, with covers secured between the braces to enclose at least part of the track, and with
braces of adjoining modules substantially sealing against each other.
There is still further provided for each end brace of a module to include a flange securable to
a complimentary flange of an end brace of an adjoining module, operatively allowing
modules to be secured end to end.
The invention further provided for the race of the track to be comprised of an elongate beam,
preferably a hollow beam, preferably a hollow steel beam.
These and other features of the invention are described in more detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of a bogie, a rail transportation system using such a bogie, and a
track for such a rail transportation system according to the invention is described by way of
example only and with reference to the accompanying drawings in which:
Figure 1 is an isometric view first embodiment of a bogie according to the invention
shown on a track according to the invention;
Figure 2 is a cross sectional view of the bogie of Figure 1;
Figure 3 is a side elevation of the bogie of Figure 1;
Figure 4 is a side view of the bogie of Figure 1 on a track according to the invention
with a load suspended from it;
Figure 5 is a side elevation view of a bogie according to Figure 1 accelerating from
rest;
Figure 6 is a side elevation view of a bogie according to Figure 1 decelerating;
Figure 7 is a side elevation view of a bogie according to Figure 1 traveling up an
incline;
Figure 8 is an isometric view of an intersection in a track according to the invention;
and
Figure 9 is a plan view of the intersection of Figure 8.
DETAILED DESCRIPTION OF THE INVENTION
A bogie (1) according to the invention is, shown in detail in Figures 1 to 3, is configured to
operate on a track (2) having track surfaces (3, 4) on opposite sides thereof and a slot (5)
extending along substantially the centre of the track (2). The track (2) is provided with track
intersections (6) at which guidance means (37) associated with the bogie (1) is operable to
guide the bogie ( 1 ) onto a selected track (2A, 2B) leading from the track intersection (6).
The bogie (1) is designed to carry a load (7) and be driven and guided on its own. Several of
the bogies may also be connected to work in unison and carry greater loads.
Each bogie (1) is however configured to be able to operate independently from other bogies
and to be driven along the track (2). It therefore needs only to carry its own weight and that of
its load (7). The bogie (1) also includes load attachment means (8) that allows different types
of loads to be carried by the bogie (1), allowing the bogie ( 1 ) to perform multiple transport
functions. This includes allowing the bogie to transport a load by it being suspended form
the bogie ( 1 ) , it being pulled by the bogie ( 1) and it being pushed by the bogie ( 1) .
To achieve this, the bogie ( 1 ) comprises a load-bearing driven wheel (9) connected to a
motor ( 10) operatively to be driven thereby on a first (3) of the two track surfaces. This first
track surface (3) is the upper track surface in this embodiment. A load support shaft ( 1 1)
extends from the driven wheel (10) operatively through the slot (5) in the track (2) and
terminates in the load support means (8).
The bogie ( 1 ) further includes a first pinch wheel ( 12) rotatably secured in a forward position
(20) in respect of the support shaft ( 1 1) and a second pinch wheel ( 13) rotatably secured in
rearward position (21 ) in respect of the support shaft ( 1 1) . Both the first ( 12) and second (13)
pinch wheels are located between the driven wheel (9) and the load support means (8) to run
on the second (4) of the two track surfaces. This second track surface (4) is the bottom track
surface in this embodiment.
Between them the driven wheel (9) and pinch wheels ( 12, 13) clamp the bogie ( 1 ) to the
opposing track surfaces (3, 4), and thus to the track (2).
The driven wheel (9) comprises a set of two axially aligned driven wheels (9A, 9B) configured
such that they both run on the first (3) of the two track surfaces on opposing sides of the slot
(5) in the track (2). The two driven wheels (9A, 9B) are axially connected.
Similarly, each pinch wheel (12, 13) comprises a set of two axially aligned and connected
pinch wheels (12A, 12B; and 13A, 13B), to form two pinch wheel sets ( 12, 13). Each pinch
wheel set (12, 13) is configured such that in each set the two pinch wheels run on the second
(4) of the two track surfaces on opposing sides of the slot (5) in the track (5), in other words
the right pinch wheels (12A, 13A) run on the right side of the slot (5) and the left pinch
wheels ( 12B, 13B) run on the left side of the slot (5), on the second (4) of the track surfaces .
The bogie (1) includes on its load support shaft ( 1 1) a pinch wheel bracket (14), with a
forward end and rearward end, extending aligned with the longitudinal axis of the bogie ( 1 ) -
thus they are operatively aligned with the slot (5) in the track (2).
The pinch wheels sets (12, 13) are rotatably secured ( 15) to the respective ends of the pinch
wheel bracket (14).
The two pinch wheel sets ( 12, 13) are orientated parallel to the track (2), at least when the
bogie (1) is at rest as will be explained in more detail below.
The pinch wheel bracket ( 14) is secured just below the bottom (4) of the track (2).
The ratio of the distance between the axis (15) of the rear pinch wheel set ( 1 ) and the
attachment of the pinch wheel bracket (14) to the load support shaft ( 1 1) to the distance
between the attachment of the pinch wheel bracket (14) and the load support means (8) is
variable depending upon how much friction is required between the driven wheels (9) and the
first (3) of the two track surfaces to create the optimum amount of traction that is required for
any specific set of circumstances.
More specifically, the ratio is determined by taking into consideration the friction coefficient
between the running surface of the (18) driven wheel (9) and the track races ( 17) of the track
(2) on which the bogie ( 1 ) is intended for use, specifically whether it is predominantly
horizontal or whether it also includes some steep angles (incline or decline).
If the bogie (1) is predominantly operated horizontally, then the ratio is selected to be
between 1:2 and 1:5.
If the bogie (1) is operated, at least on part of a track, at steep angles then the ratio is
selected to be about 1:5.
In this embodiment the bogie (1) is intended to be used on a track (2) which includes steep
angles, and the ratio is thus predetermined to be about 1:5.
It should be further noted that the specific ratio is also dependant on the choice of material
for the running surface ( 18) of the driven wheel (9). If it is made of a resiliently compressible
material such as rubber or plastics material as compared to a substantially incompressible
material such as metal, more specifically steel, then the ratio may be reduced.
As will be further apparent from viewing Figures 1 to 3, the bogie (1) includes a frame ( 19)
secured proximate the end of the load support shaft ( 1 1). The frame ( 19) extends to two
opposing ends ( 19A, 19B), both of which are aligned with the longitudinal axis of the bogie
( 1) and thus aligned with the slot (5) in the track (2). A first end ( 19A) of the frame ( 19) is thus
directed to a forward position (20) in respect of the bogie (1) and its load support shaft ( 1 1)
and second end ( 19B) to the rearward position (21 ) in respect of the load support shaft ( 1 1).
Each end (19A, 19B) of the frame ( 19) is directed towards the pinch wheel (12, 13) on its
side (20, 21) of the load support shaft ( 1 1).
The frame (19) is configured to carry further equipment associated with the bogie ( 1 ) . Each
arm ( 19A, 19B) carries a battery (22A, 22B) secured to it. The frame ( 19) further carries the
motor (10) and control equipment (23) associated with the bogie (1). The control equipment
(23) includes electronic control for the drive and communications equipment.
The motor (10) may be a linear motor or a rotary motor, and in this embodiment it is a rotary
motor ( 1 0). The motor ( 10) and the driven wheel (9) are rotatably secured by means of a
drive belt, in this embodiment comprising a drive chain (24), that is rotatably located around
sprockets (25, 26) on each of a drive shaft of the motor ( 10) and a secondary axis (27)
proximate the axis (16) of the driven wheel (9). The secondary axis (27) and the axis ( 16) of
the driven wheel (9) are both provided with gears (not shown) that are meshed together
which provides an effective predetermined gear ratio between the rotary motor (10) and the
driven wheel (9).
The bogie (1) is further provided with an electrical contact (28) extending from its top, as
shown in Figures 1 to 3. The electrical contact (28) is configured to be in resiliently biased
contact with an electrical rail (30) extending along the top of the track (2). The electrical
contact (28) is connected to the control system (23) of the bogie (1) and charges the
batteries (22A, 22B). The bogie ( 1 ) is configured such that the motor ( 10) is powered from
the batteries (22A, 22B) and these are charged by the electrical connection (28, 30). This
allows the bogie (1) to continue driving even if there is an interruption in power supply to the
track (2) or through sections of the track that may not be electrical powered. This also allows
the transport system to operate through remote areas where electrical supply may not be
available.
The bogie ( 1 ) is also provided with a hoist lug (29) from its operative top, to assist in
removing it for maintenance and placing it on the track (2) again.
As will further be apparent from Figures 1 to 3 the arms ( 19A, 19B) terminate in directional
control wheels (31 A and 3 1B; 3 1C and 3 1 D). These directional control wheels (31 A and 3 1B;
3 1C and 3 1D) extend above the pinch wheels into the slot (5), where they run on opposite
sides of the inside the slot (5). These directional control wheels (31 A and 3 1B; 3 1C and 3 1D)
prevent sideways movement of the bogie during forward or rearward motion, by guiding the
bogie (1) against the inside of the slot (5).
The load support means (8) comprises a load bearing secured to the end of the load support
shaft ( 1 1), extending through the sides of the frame (19). This allows a load (7) to be
suspended from the load support shaft ( 1 1) and to remain vertically orientated irrespective of
the inclination that the track (2) follows, freely pivoting on the load bearing (8).
In use the bogie ( 1 ) may be operated with or without a load (7), and in solo or in-line with one
or more other bogies.
When used alone the bogie (7) is, for example, loaded by suspending a load (7) from the
load support shaft (8), on the load support bearing (8). This load (7) may comprise a bucket
filled with ore, as shown in Figures 4 to 7. In this example the bogie ( 1 ) is used to move the
load of ore (7) between two points, for example from a mine to an ore processing plant.
Initially after being loaded, the bogie (1) is at rest and the load (7) is suspended vertically
from it. In this position, the pinch wheels ( 12, 13) are all spaced apart (42) from the bottom of
the track, i.e. the second (4) of the track surfaces. This is shown in Figure 4.
With the bogie (1) loaded it is brought into motion by activation of the motor (10), to drive the
driven wheel (9) through the chain (24). With the load (7) initially completely vertically
suspended from the bogie (1), the running surface (18) of the driven wheel (9) is forced onto
the upper race (17) of the track (2). The static coefficient of friction between the driven wheel
running surface ( 18) and the upper race (17) is sufficient to allow the electric rotary motor
(10) to drive the bogie (1) forward, even though the running surface ( 18) of the driven wheel
(9) is steel.
As shown in Figure 5, when the bogie (1) moves forward (32), the inertia of the load (7)
causes the load (7) to effectively swing (33) behind the longitudinal axis (34) of the load
support shaft ( 1 1), which at rest on a horizontal track is of course vertical.
This pivots the bogie (1) clockwise in this embodiment around the axis ( 16) of the driven
wheel (9) and forces the then rearward pinch wheel ( 12) against (44) the second (4) of the
two track surfaces, i.e. up against the bottom of the track behind the load support shaft ( 1 1).
The forward pinch wheel ( 13) moves slightly further away (43) from the second (4) of the
track surfaces. As mentioned above, initially, at rest, the two pinch wheels ( 12, 13) do not
actually touch the bottom (4) of the track, but as soon as the bogie (1) comes into the motion,
the inertia of the load (7) forces the rearward pinch wheel (12) into contact (44) with bottom
(4) of the track (2).
The rearward rotation of the bogie (1) thus forces the rearward pinch wheel set (12) into
contact (44) with the bottom (4) of the track (2). This clamps the bogie (1) to the track (2) and
increases the friction between the driven wheel running surfaces ( 18) and the upper race
(17) of the track (2). With increased friction the bogie (1) overcomes any potential slippage
on the track (2) and is thus able to pull greater loads.
The greater the load the greater the rearward rotation of the bogie ( 1 ) around the axis of the
driven wheel (9) and the greater the increase in clamping force. This translates to greater
friction and a greater ability to pull a load. The clamping force of the bogie ( 1 ) onto the track
(2) is thus dependant on the weight of the load (7), with a greater load generating a greater
clamping force, which overcomes the greater likelihood of slippage. As will be shown below it
is also dependant on the inclination of the track (2).
The clamping force is determined by the ratio of the distance between the axis (15) of the
rearward pinch wheel ( 12) and the attachment of the pinch wheel bracket (14) to the load
support shaft ( 1 1) to the distance between the attachment of the pinch wheel bracket (14)
and the load support means (8). As mentioned above, for a bogie (1) that is operated, at
least on part of a track (2), with steep angles such as in the present embodiment, the ratio is
set at 1:5.
The force with which the bogie (1) is clamped to the track also depends on the weight of its
load (7), the incline or decline at which it is moving and whether it is accelerating,
decelerating or driving at a steady speed.
As mentioned above, upon acceleration of the bogie (1), the rearward pinch wheels (12) are
forced against (44) the second (4) of the track surfaces, operatively increasing the clamping
force between the driven wheel (9) and the rearward pinch wheel ( 12) to increase friction
between the driven wheel running surface ( 18) and the race (17) of the first (3) of the two
track surfaces to assist with acceleration of the bogie ( 1 ) and the load (7) secured to it.
Upon reaching a steady speed the force required to maintain the forward speed of the bogie
( 1 ) is lower than the force required to accelerate the bogie (1) from rest. The rearward pinch
wheel set (12) is then forced with a lesser force, or not at all, against the second (3) of the
track surfaces compared to when the bogie (1) is accelerated from rest. The clamping force
is thus commensurately lower compared to when the bogie (1) is accelerated from rest, and
may on a horizontal section of the track (2) be zero. This will be similar to the situation shown
in Figure 4 where the bogie is at rest. This allows the bogie (1) to continue moving with a
lower clamping force between the driven wheel (9) and the then rearward pinch wheel (13) at
steady speed than during acceleration or a zero clamping force. This improves the energy
efficiency of the bogie (1), since it uses less electrical power to be driven forward at steady
speed than required for acceleration.
As shown in Figure 6, upon deceleration of the bogie (1) as a result of braking of the driven
wheel (9) - which reduces the forward (32) speed of the bogie ( 1 ) - the inertia (35) of the load
(7) pivots the bogie (1) anti-clockwise in this embodiment, which is the reverse of what
happens under acceleration.
This pivoting of the bogie ( 1 ) forces the pinch wheel ( 13) located in the then forward position
(20) relative to the direction of movement (32) of the bogie (1) against (46) the second (4) of
the track surfaces. This increases the clamping force between the driven wheel (9) and the
forward pinch wheel set ( 13) to increase friction between the driven wheel running surface
(18) and race ( 17) of the first (3) of the two track surfaces to assist with deceleration of the
bogie ( 1 ) and load (7) secured to it, either to reduce its speed or bring it to rest. The rearward
pinch wheel ( 12) moves slightly further away (45) from the second (4) of the track surfaces.
The forward (13) and rearward (12) pinch wheels thus both act to increase the clamping
force of the bogie (1) onto the track (2) during acceleration, steady driving and deceleration.
The bogie (1) can also be turned around and driven in the opposite direction, loaded or
unloaded, and the pinch wheels ( 12, 13) will perform in the same manner, with the then
rearward pinch wheel set ( 13) being forced against the second (4) of the track surfaces upon
acceleration and traveling at steady speed, and the leading pinch wheel doing the same
upon deceleration.
Considering the design of the bogie and the track, it should be evident that the track (2) can
be inclined or declined. In fact, the track can be to completely vertical up or down. The
limitation here will only be the dimensions of the load (7) secured to the load support shaft
( 1 1) , it being necessary that the length of the load container is limited to not extend beyond
the pinch wheels (12, 13) when the track (2) is at vertical. This is to prevent the load
container from contacting the second (4) of the track surfaces.
As will be appreciated, to have the bogie (1) with a load (7) climb or descend a vertical
incline or decline it requires sufficient clamping force of the bogie (1) to the track (2). This is
achieved by the increased clamping force of the bogie (1) to the track as described above.
When the track (2) is at vertical the clamping force for a specific load will be at its greatest. If
the load (7) is heavier the clamping force will be greater, and vice versa. Again, the clamping
force is provided as much as is required by the bogie ( 1 ) to move along the track (2).
An example of the bogie (1) driving up an incline is shown in Figure 7. It can be seen that
gravity causes the load (7) to swing by the same angle (Q) to the longitudinal axis of the load
support shaft as the angle (Q) of the incline (36). This pivoting of the load (7) causes the
bogie (1) to pivot clockwise, in this embodiment, around the axis (16) of the driven wheel (9),
which has the same effect of increasing the clamping force between the rearward pinch
wheel set ( 12) as is experienced during acceleration.
The rearward pinch wheel (12) is thus forced against (47) the second of the two track
surfaces, and the forward pinch wheel (13) moves slightly further away (48) from the second
(4) of the track surfaces.
Similarly, if the bogie (1) travels down an incline (not shown) the load (7) will pivot forward to
pivot the bogie, in this embodiment, in an anticlockwise direction with the same effect as is
experienced during deceleration.
When the bogie (2) has climbed up or down a vertical section of the track (2) and travels at
steady speed and on a level part of the track the clamping force will again reduce to the
lower amount required to move the bogie (2) and its load (7) forward, being even zero if the
track (2) is complete horizontal. The clamping force therefore dynamically and automatically
adjusts depending on track (2) inclination and the weight of the load (7), ensuring that the
bogie (1) can continue to move the load (7) on the track (2).
When the track (2) comes to a track intersection (6) as shown in Figures 8 and 9, the
guidance means (37) is activated to force the bogie (2) into one of the two tracks (2A, 2B)
leading from the intersection (6). As shown in Figures 8 and 9, leading up to the intersection
(6) the track widens (56), and the elongate slot (5) spits into two, one slot (38, 39) leading
into the centre of each of the two tracks (2A, 2B) leading from the intersection (6). Aligned
with each slot (38, 39) is a guide member (40, 41) located above the track (2). Each guide
member comprises a rib (40, 4 1) that includes a lead-in section.
In respect of the bogie ( 1 ) , as shown in Figures 1 to 3, the guide means (37) comprises a
frame (49) secured to the top of the bogie (1), above the driven wheel (9). Secured to the
frame (49) is a first transverse bracket (50) which extends towards the sides of the bogie (1).
Proximate each of the opposed ends of this transverse bracket (50) are secured rear guide
wheels (51 , 52).
The frame (49) further extends away from its connection point the bogie (1) longitudinally
aligned with the bogie ( 1 ) . At the forward end of frame (49) there is secured a second
transverse bracket (53). Proximate each of the opposed ends of this second transverse
bracket (53) are secured forward guide wheels (54, 55).
The forward and rearward guide wheels (51 , 52, 54, and 55) are arranged that the forward
and rearward guide wheels (51 and 54; 52 and 55) operate in concert. Each of the sets of
guide wheels is axially movable between a lowered position and a raised position, with an
intermediary neutral position.
In addition, the guide wheels (51 and 54; 52 and 55) are interconnected by a chain drive (not
shown) secured to an electrical motor (not shown), to move them between the lowered and
raised positions. The guide wheels (51 and 54; 52 and 55) are configured that if they are
raised on one side, then the guide wheels on the opposing side are lowered. Both sets of
guide wheels may be in the neutral position at the same time, but only one set of guide
wheels (51 and 54; or 52 and 55) can be raised at any time.
In the raised position the guide wheels (51 and 54; 52 and 55) are aligned with the outside of
the guide member rib (40, 41) on its side of the track (2). For example, if the bogie (1) needs
to take the track (2A) leading to the right of a track intersection (6) then the right side's guide
wheels (52, 55) are raised The guide wheels (52 55) will against the right side, i.e. the
outside, of the guide rib (40) of the right track (2A).
The guide rib (40) follows the right track (2A) and the bogie ( 1 ) is thus forced to the right side
of the track intersection (6). As mentioned above the driven wheel (9) is set of two driven
wheels (9A, 9B), each of which is wider than the slot (5) extending along the track (2). The
right driven wheel (9B) stays on the race ( 17B) on the right side of the track (2), and
continues traveling along this.
The left driven wheel (9A) travels across the slot (38) that leads into the left track (2A) to
follow to the right track (2B). Since the driven wheels (9A, 9B) are wider than the slots (5, 38,
39) the right side, i.e. the inside with respect to the bogie ( 1 ) , of the left driven wheel (9A)
engages the left race (17A) of the right track (2A) before the outside of the left driven wheel
(9A) passes over the slot (5, 38), which is at the intersection (6), as shown in Figure 9. The
left driven wheel (9A) is thus always supported by the track (2).
With the left side guide wheels (51 , 54) in the lowered position the left side guide rib (41) is
not interacted with.
If the bogie (1) had to turn left the process would just be changed with right for left.
The guide means (37) may be controlled remotely from a central control room. Each bogie
(1) includes a control system which is preloaded with directions. When it arrives at a specific
track intersection (6) it receives from a track transponder a signal identifying the track
intersection (6) which is then correlated to the planned route stored on the bogie control
system (23). The bogie ( 1 ) then transmits a signal which is received by a receiver associated
with one of the electromagnetic elements - essentially just a left or right signal. In the
example above it would be a "right" signal.
In another configuration the bogie (1) has a unique identifier that announces its arrival at a
track intersection (6), for example by way of a transponder. This will allow the control system
to know when a specific bogie approaches a track intersection (6) which will then allow the
control system to determine from a planned route into which direction the bogie ( 1 ) should be
directed. A control signal is then transmitted to a track control system which activates the
guide means (37).
When the bogie ( 1 ) has passed through the intersection (6) it awaits the next intersection
identifier to determine further instructions to be sent.
A track intersection (6) is designed to include always one track that continues straight (2B),
and one track (2A) that diverts from it, as shown in Figure 9. This ensures that in the event
the guide means (37) experiences a failure that the bogie continues driving on its original
track, instead of crashing into the split between the two tracks (2A, 2B).
If the bogie (1) has to come to a halt or accelerate the remote control system or the on-board
control system can similarly control the drive means to slow down or speed up. For this it will
receive a signal from a transponder which is interpreted by the bogie control system (23) as
a "stop", "change speed to X kph", or "accelerate to normal travel speed". There are many
permutations of predetermined instructions that may be coded into a track transponder which
provides passive instructions to each bogie passing it.
The bogie (1) will also be provided with a receiver which receives transponder signals from
other bogies. This will allow the on-board control system (23) to bring a bogie (1) to a
standstill before driving into another bogie, for example if bogies are waiting to be offloaded
or in the event that a bogie ( 1 ) develop a mechanical problem on a track (2).
This control over the bogies may also be used to allow one or more bogies to line up behind
another bogie and assist it, if for example the first bogie has a breakdown. Using this logic,
and empty bogie may also be sent back to assist from the front of broken down bogie.
For this the bogies are fitted with couplings (not shown) to their front and rears allowing for
such assisted movement. This may also be used pre-planned, where a load exceeds the
drive capability of one bogie.
For such planned multi-bogie operations the load (7) may be supported between two bogies
by being suspended between both their load support shafts ( 1 1). This allows two bogies to
be driven optimally in terms of clamping force with the load (7) working equally onto both
bogies.
The track does not only have to be elevated as shown in the drawings. The bogie ( 1 ) may
also be used on a track located on the ground. The load support shaft will still extend below
the pinch wheels (12, 13) but the load may be trailed behind the bogie on the track. The end
of the load support shaft needs to extend below the pinch wheels to provide the
predetermined ratio between the axis of the driven wheel and the attachment of the pinch
wheel bracket to the load support shaft to the distance between the axis of the driven wheel
and the load support bearing.
It should be appreciated that the track height need not be enormous to achieve clamping The
distance between the attachment of the pinch wheel bracket and end of the load support
shaft need not be enormous to achieve effective clamping and hence the bogie can operate
with clearance as little as 100 mm to 250mm under the track (i.e. below the second of the
track surfaces). This allows the system to easily be installed on the ground.
It will be appreciated that the above described embodiment is given by way of example only
and it not intended to limit the scope of the invention. It is possible to alter aspects thereof, as
already indicated above in respect of the linear motor and ground based track, without
departing from the essence of the invention.
It is for example also possible to drive the pinch wheels, alone or in combination with the
load-bearing wheel.
It is also possible to pull a load behind the bogie, where it may run on wheels on the track. A
load may also be pushed in front of the bogie. The bogie may be used thus essentially as a
locomotive pulling or pushing one or more other bogies or freight cars.
It is also possible for the electrical rail to power, through the electrical contact, the motor
directly and for the batteries to be dispensed with completely. This would be useful in
applications where there is a consistent power supply to the track, and the bogie can then be
operated without batteries which reduce the weight of the bogie.

Claim
A rail transport bogie configured to operate on a track having track surfaces on
opposite sides thereof and a slot through the slot extending along substantially
the centre of the track, the bogie comprising a load-bearing wheel to run on a first
of the two track surfaces, a support shaft extending from the load-bearing wheel
operatively through the slot in the track and terminating in load support means, a
first pinch wheel rotatably secured in a forward position in respect of the support
shaft and a second pinch wheel rotatably secured in rearward position in respect
of the support shaft, with both the first and second pinch wheels located between
the load-bearing wheel and load support means to run on the second of the two
track surfaces, the load-bearing wheel and pinch wheels clamping between them
the bogie to the opposing track surfaces, and at least one of the load-bearing
wheel and either or both of the pinch wheels connected to a motor operatively to
be driven thereby to comprise a driven wheel for the bogie.
A bogie as claimed in claim 1 in which movement of the bogie in a forward or
rearward direction is effected by forward or rearward driving of the driven wheel.
A bogie as claimed in claim 1 or 2 configured, upon acceleration thereof as a
result of rotation of the driven wheel, for inertia of a load operatively secured to
the load support means to pivot the bogie on the axis of the load-bearing wheel to
force the pinch wheel located in the then rearward position relative to the direction
of movement of the bogie against the second of the track surfaces, operatively
increasing the clamping force between the load-bearing wheel and the rearward
pinch wheel to increase friction between the load-bearing wheel and first of the
two track surfaces to assist with acceleration of the bogie and the load secured to
it.
A bogie as claimed in any one of claims 1 to 3 configured, upon deceleration
thereof as a result of braking of any of the wheels of the bogie, for inertia of a load
operatively secured to the load support means to pivot the bogie on the axis of the
load-bearing wheel to force the pinch wheel located in the then forward position
relative to the direction of movement of the bogie against the second of the track
surfaces, operatively increasing the clamping force between the load-bearing
wheel and the forward pinch wheel to increase friction between the load-bearing
wheel and first of the two track surfaces to assist with deceleration of the bogie
and load secured to it, either to reduce its speed or bring it to rest.
A bogie as claimed in any one of claims 1 to 4 configured, upon reaching a steady
speed at which the force required to maintain the forward speed of the bogie is
lower than the force required to accelerate the bogie from rest, for the rearward
pinch wheel to be forced with a lesser force, or not to be forced at all, against the
second of the track surfaces and respectively for the clamping force to be
commensurately lower compared to when the bogie is accelerated from rest or for
the clamping force to be zero, operatively allowing the bogie to move with a lower
clamping force between the load-bearing wheel and the then rearward pinch
wheel at steady speed than at acceleration of the bogie.
A bogie as claimed in any one of the preceding claims in which the driven wheel
comprises a set of two axially aligned driven wheels, with the driven wheels
configured such that they both run on either the first or the second of the two track
surfaces on opposing sides of the slot in the track.
A bogie as claimed in claim 6 in which the two driven wheels are axially
connected.
A bogie as claimed in any of the preceding claims in which each pinch wheel
comprises a set of two axially aligned pinch wheels, with each pinch wheel set
configured such that in each set the two pinch wheels run on the second of the
two track surfaces on opposing sides of the slot in the track.
A bogie as claimed in claim 8 in which of each pinch wheel set the two pinch
wheels are axially connected.
A bogie as claimed in any one of the preceding claims which includes a pinch
wheel bracket secured to the load support shaft, with the bracket extending to two
opposing ends, a first end to a forward position in respect of the support shaft and
second end to a rearward position in respect of the support shaft, with the first
pinch wheel rotatably secured to the first end and the second pinch wheel
rotatably secured to the second end of the pinch wheel bracket.
11. A bogie as claimed in any one of the preceding claims in which the load-bearing
wheel comprises the driven wheel.
12. A bogie as claimed in claim 10 or 11 in which the ratio of the distance between
the axis of the rearward pinch wheel and the attachment of the pinch wheel
bracket to the load support shaft to the distance between the attachment of the
pinch wheel bracket and the load support means is variable depending upon how
much friction is required between the driven wheels and the track surfaces to
create the optimum amount of traction that is required for any specific set of
circumstances.
13. A bogie as claimed in claim 10 or 11 in which the bogie is predominantly operated
horizontally, and the ratio of the distance between the axis of the rearward pinch
wheel and the attachment of the pinch wheel bracket to the load support shaft to
the distance between the attachment of the pinch wheel bracket and the load
support means is between 1:2 and 1:5.
14. A bogie as claimed in claim 13 in which the ratio is about 1:3.
15. A bogie as claimed in claim 10 or 11 in which the bogie is operated, at least on
part of a track, at steep angles, and the ratio of the distance between the axis of
the rearward pinch wheel and the attachment of the pinch wheel bracket to the
load support shaft to the distance between the attachment of the pinch wheel
bracket and the load support means is at least 1:5.
16. A bogie as claimed in claim 15 in which load-bearing wheel and the pinch wheels
have resiliently compressible running surfaces, preferably comprised of rubber or
plastics material, alternatively the load-bearing wheel and the pinch wheels have
substantially incompressible running surfaces, preferably comprised of metal,
further preferably steel.
17. A bogie as claimed in any one of the preceding claims in which the motor
comprises a linear motor or a rotary motor.
18. A bogie as claimed in claim 17 in which a linear motor reaction plate or reaction
plates forming part of the linear motor is secured to the load support shaft,
preferably above the pinch wheel bracket.
19. A bogie as claimed in claim 17 in which the motor comprises a rotary motor
secured to the load support shaft, preferably below the pinch wheels.
20. A bogie as claimed in any of the preceding claims which includes guidance
means operable at each track intersection to move the bogie laterally across the
track towards one side of the track or another, depending on which track the
bogie is to follow leading from the track intersection, the guidance means
comprising at least one guide wheel being movable between a neutral position
and a guiding position, with the guide wheel configured in its guiding position to
interact with a guide member that extends along a track leading from a track
intersection to cause the bogie to follow such track, and the guide wheel
configured to not interact with any guide member when it is located in its neutral
position.
2 1. A bogie as claimed in any one of claims 1 to 19 which includes guidance means
operable at each track intersection to move the bogie laterally across the track
towards one side of the track or another, depending on which track the bogie is to
follow leading from the track intersection, the guidance means comprising at least
two guide wheels located on opposing sides of a longitudinal axis of the bogie and
being movable between a neutral position and a guiding position, with each guide
wheel configured in its guiding position to interact with a guide member on its side
of the longitudinal axis of the bogie that extends along a track leading from a track
intersection to cause the bogie to follow such track, and the guide wheels
configured to not interact with any guide member when they are located in their
neutral positions.
22. A bogie as claimed in claim 2 1 in which the two guide wheels are connected and
configured such that both guide wheels cannot simultaneously be in their
respective guiding positions.
23. A bogie as claimed in any one of the preceding claims that includes an electrical
contact configured complimentary to an electrical rail associated with the track
operatively to electrically connect the bogie with the rail.
24. A bogie as claimed in claim 23 in which the electrical contact extends from above
and to the side of the driven wheel.
25. A bogie as claimed in claim 23 or 24 in which the contact is electrically connected
and configured to charge the battery or power the motor.
26. A bogie as claimed claim in any one of claims 17 to 25 which include drive control
means secured to the load support shaft proximate the motor, preferably on an
opposing side of the load support shaft relative to the motor.
27. A bogie as claimed in any one of the preceding claims in which the motor and the
driven wheel are rotatably secured by means of a drive belt or a drive shaft.
28. A bogie as claimed in claim 27 in which the drive belt comprises a chain
extending around sprockets on each of a drive shaft motor and the axis of the
driven wheel.
29. A bogie as claimed in any one of claims 1 to 26 in which the motor is connected to
the driven wheel via a sprocket secured to a secondary axis proximate the axis of
the driven wheel, with the secondary axis and the axis of the driven wheel being
rotatably secured to each other by meshed gears having a predetermined gear
ratio.
30. A bogie as claimed in claim 27 in which the drive shaft comprises a secondary
drive shaft connected from the motor drive shaft to the axis of the driven wheel
using a coupling, preferably a differential coupling.
3 1 . A bogie as claimed in any one of the preceding claims in which the load support
means comprises a load bearing secured to the end of the load support shaft.
32. A bogie as claimed in any one of the preceding claims in which the load may be
secured to the load support means enabling the load to be suspended from the
bogie, pulled behind the bogie or pushed in front of the bogie.
33. A bogie as claimed in any one of the preceding claims which includes a frame
secured proximate the load support shaft end, the frame extending to two
opposing ends, a first end to a forward position in respect of the support shaft and
second end to a rearward position in respect of the support shaft, and each end
extends into an arm directed towards the pinch wheel on its side of the load
support shaft, with each arm carrying a battery.
34. A bogie as claimed in claim 33 in which each arm terminates in at least one
directional control wheel operatively running on the sides of the slot in the track.
35. A bogie as claimed in claim 32 or 34 in which each arm terminates in a set of
spaced apart directional control wheels operatively running on opposing sides of
the slot in the track, the running surfaces of the directional control wheels spaced
apart by a distance complimentary to the width of the slot.
36. A rail transportation system comprising a network of tracks, a plurality of bogies
as claimed in any one of claims 1 to 35 each of which has a driven wheel
arranged to run on and be supported by the track and which are capable of
supporting, pulling or pushing a load secured to the bogie, each bogie being
driven along the track and including guidance means which allows it to switch
from a track leading to a track intersection to a preselected track leaving the track
intersection without any load-bearing wheel of the bogie being unsupported by the
track.
37. A system as claimed in claim 36 in which the track intersection includes no
moving parts to enable bogie switching.
38. A system as claimed in claim 36 or 37 in which the track comprises an elongate
set of races spaced apart by an elongate slot with the set of races kept in spatial
relation to each other by means of a frame extending from the sides of the races.
39. A track for a system as claimed in any one of claims 36 to 38 that is modular and
the modules include straight sections and curved sections, and each module
comprises a set of races spaced apart by an elongate slot through the track
operatively allowing the support shaft of a bogie to extend through the slot, with
the set of races kept in spatial relation to each other by means of a frame
extending across the track, and with each race being provided with a wear
resistant lining removably secured to its top, bottom and its side facing the slot.
40. A track as claimed in claim 39 in which the frame includes a brace proximate the
end of each module with each brace having a set of spaced apart legs, each of
which is secured to a side of the track, with covers secured between the braces to
enclose at least part of the track, and with braces of adjoining modules
substantially sealing against each other.
4 1. A track as claimed in claim 40 in which each end brace of a module includes a
flange securable to a complimentary flange of an end brace of an adjoining
module, operatively allowing modules to be secured end to end.
42. A track as claimed in any one of claims 39 to 4 1 in which the race of the track is
comprised of an elongate beam, preferably a hollow beam, preferably a hollow
steel beam.