Note: Descriptions are shown in the official language in which they were submitted.
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TITLE: CROSS-TIE
Field of the Invention
The present invention relates generally to the field of
railway tracks, and more specifically to cross-ties that
are used with railway tracks.
BACKGROUND OF THE INi7ENTION
Railway vehicles that use linear induction mators (LIM) as
their primary source of propulsion are known in the art.
In general, linear induction motors (LIM) used by railway
vehicles consist of a primary portion that is supported
under the railway vehicle, and a reaction rail that is
supported on the railway track. As such, railway tracks
built for LIM railway vehicles include a pair of running
rails for supporting the wheels of the railway vehicle,
and a reaction rail for interfacing with the primary
portion of the linear induction motor. In addition,
railway tracks for LIM railway veh_cles include at least
one power rail that is generally positioned above, and
perpendicularly to the running rails and the reaction
rail. It is the one or more power rails that. supply power
to the railway vehicle as it travels over the railway
track.
Traditionally, railway tracks for LIM railway vehicles are
formed by fastening each of the running rails, the
reaction rail and the one or more power rails to a
concrete guideway of the railway track via separate rail
fasteners. As such, each of the rails is secured to the
concrete guideway of the railway track independently. A
deficiency with this manner of building the railway track
is that each one of the rails requires a separate rail
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fastening arrangement, which makes the railway track time-
consuming and expensive to install. A further deficiency
with such traditional railway track is that it is
difficult to control the relative positioning between the
running rails, the reaction rails and the one or more
power rails, which is important for the proper operation
of the LIM rail vehicle over the track. As such, at the
time of installation, the position of each rail must be
adjusted such that it is properly positioned in relation
to the other rails.
U.S. Patent No. 5,314,115 describes a cross-tie that
attempts to overcome at least some of the deficiencies
with such traditional railway tracks. The cross-tie
described by U.S. Patent No. 5,314,115 supports both the
pair of running rai.l_s and the reaction rail, and is
operative for securing these rails to the concrete
guideway of the railway track. A deficiency with this
cross-tie is that it does not take into consideration the
relative positioning of the power rail in relation to the
running rails and the reaction rails. As such, the precise
positioning of the power rail in relation to the pair of
running rails and the reaction rail needs to be adjusted
at the time of installation. In addition, the fact that
the running rails and the reaction rails are mounted to
the guideway separately from the power rail requires
additional fastening studs which results in more work for
the person installing the track, and additional parts that
can be costly.
In light of this background, there exists a need in the
industry for a more efficient, less cumbersome and less
costly manner of building and maintaining a railway track
for LIM rail vehicles.
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Summary of the Invention
In accordance with a broad aspect, the present invention
provides a cross-tie comprising an elongated body. The
elongated body comprises a reaction rail supporting
section, two running rail supporting sections and a power
rail supporting section. The reaction rail supporting
section is adapted for supporting a reaction rail and the
two running rail supporting sections are each adapted for
supporting a respective running :rail. The power rail
supporting section is adapted for supporting at least one
power rail.
In accordance with another broad aspect, the present
invention provides an assembly comprising a cross-tie and
at least one stud assembly. The cross tie includes a
reaction rail supporting section adapted for supporting a
reaction rail, and two running rail supporting sections,
each adapted for supporting a respective running rail. The
one or more stud assemblies are adapted for securing the
cross-tie to a guideway of a railway track, and are
operative for electrically insulating the cross-tie from
the guideway.
In accordance with another broad aspect, the present
invention provides an assembly that comprises a cross-tie
and a wedge member. The cross--tie has an elongated body
that includes a reaction rail supporting section and two
running rail supporting sections. The reaction rail
supporting section is adapted for supporting a reaction
rail, and the two running rail supporting sections are
each adapted for supporting a. respective running rail.
Each running rail supporting section has a lower surface
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adapted for facing a rail guideway and an upper surface
adapted for supporting a running rail. The upper surface
is substantially parallel to the lower surface. The wedge
member is adapted to be positioned on the upper surface of
the running rail supporting section between the upper
surface and the running rail.
In accordance with yet another broad aspect, the present
invention provides an assembly comprising a cross-tie and
l0 a power rail support. The cross-tie includes a reaction
rail supporting section, two running ra_'~1 supporting
sections and a power rail supporting section., The reaction
rail supporting section is operative for supporting a
reaction rail and the two running rail supporting sections
are each adapted for supporting a respective running rail.
The power rail support is adapted for being removably
connected to the power rail supporting section and is
adapted for having at least one power rail connected
thereto.
2a
These and other aspects and features of the present
invention will now become apparent to those of ordinary
skill in the art upon review of the following description
of specific embodiments of the invention in conjunction
with the accompanying drawings.
Brief Description of the Drawings
A detailed description of the embodiments of the present
invention is provided. herein below, by way of example
only, with reference to the accompanying drawings, in
which:
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Figure 1 is a perspective view of a railway track for an
LIM rail vehicle in accordance with a non-limiting example
of implementation of the present invention;
5 Figure 2 is a side view of a cross-tie for use with the
railway track in accordance with a non--limiting example of
implementation of the present invention;
Figure 3 is an expanded view of the portion of Figure 2
contained in circle A, in accordance with a non-limiting
example of implementation of the present invention;
Figure 4 is an expanded view of the portion of Figure 2
contained in circle B, in accordance with a non-limiting
example of implementation of the present invention; and
Figure 5 is an expanded view of the portion of Figure 2
contained in circle C, in accordance with a non-limiting
example of implementation of the present invention; and
Figure 6 is a cross-sectional view taken along line 5-5
shown in Figure 2, in accordance with specific non-
limiting examples of implementation of the present
invention.
In the drawings, the embodiments of the invention are
illustrated by way of examples. It is to be expressly
understood that the description and drawings are only for
the purpose of illustration and are an aid for
understanding. They are not intended to be a definition of
the limits of the invention.
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DETAI?~ED DESCRIPTION
Shown in Figure 1 is a railway track 2 for a rail vehicle
(not shown) that uses a linear induction motor (LIM) as
its primary source of propulsion. The railway track 2
includes a guideway 4 that is typically formed of
concrete, and a plurality of cross-ties 10. The cross-ties
are operative to support a pair of running rails 6, a
10 reaction rail 8 and at least one power rail 12. In the
non-limiting example of implementation shown in Figure 1,,
the cross-tie 10 is operative to support two power rails
12.
I5 As shown, the running rails 6 are positioned on the cross-
tie 10 in a parallel, spaced apart relationship, such that
the wheels of the railway vehicle can travel therealong.
The reaction rail 8 is positioned between the two running
rails 6, and is operative to complete a flux path with a
primary portion of the linear induction motor located on
the railway vehicle, so as to propel or retard the railway
vehicle along the track. The power :rails 12 are positioned
perpendicular to the running rails 0 and the reaction rail
8, and are adapted for supplying power to the LIM railway
vehicle. It is to be understood that although the power
rails 12 are generally positioned perpendicularly to the
running rails 6, they could also be positioned parallel to
the running rails 6.
Shown in Figure 2, is a more detailed diagram of a cross-
tie 10 in accordance with a non-limiting example of
implementation of the present invention. The cross-tie 10
includes a generally elongated body 14 that defines two
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running rail supporting sections 16 and a reaction rail
supporting section 18. In the non-limiting embodiment
shown, one of the running rail supporting sections 16 is
generally U-shaped, in order to be able to support the
power rails 12, as will be described further on and the
other running rail supporting section 16 is generally L-
shaped. The reaction rail supporting section 18 is in the
general shape of a rectangular bar, and is positioned
between the two running rail supporting sections 16 in an
elevated position in relation to the surface of the
concrete guideway 4.
In a non-limiting example of implementation of the present
invention, the elongated body 14 of the cross-tie 10 is
formed of steel. It should be understood, however, that
other materials can be used without depari~ing from the
spirit of the invention. It should also be understood that
the two running rail supporting sections 16 and the
reaction rail supporting section 18 can be formed as one
integral piece via molding or casting. Or alternatively,
the reaction rail supporting section 18 and the running
rail supporting sections 16 can be separate pieces that
are welded together, or assembled in any other suitable
manner, in order to form the single elongated body 14.
As shown in Figure 2, the reaction rail supporting section
18 is adapted to support a reaction rail 8. In the
specific example of implementation shown, the reaction
rail 8 is connected to the reaction rail supporting
section 18 of the cross-tie 10 via a fastening arrangement
20. Shown in Figure 3 is an expanded view of the fastening
arrangement 20, as well as the portion of the reaction
rail 8, shown ir. circle A in Figure 2.
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g
Referring to Figure 3, the reaction rail 8 is formed of
two parts, namely a back iron 22 and a top-cap 24. The
cross-tie 10 of the present invention enables the back
iron 22 and the top-cap 24 to be pre-assembled prior to
being mounted to the cross-tie 10. In the non-limiting
embodiment shown, the back iron 22 a.nd the top-cap 24 are
pre-assembled via bolts 25. The fact that the back iron
22 and the top-cap 24 can be pre-assembled prior to being
mounted to the cross-tie 10 means that the reaction rail 8
can be mounted to the cross-tie i0 in one step. This
avoids having to mount the back iron. 22 and the top-cap 24
to the cross-tie 10 separately, which reduces the time
required to secure the reaction rail 8 to the cross-tie 10
during installation on site. It is typically more
expensive to assemble the components on site than to
assemble them irl a manufacturing plant. In addition, the
fact that the reaction rail 8 can be installed or removed
from the cross-tie 10 in one step, reduces the time
required to replace or repair the reaction rail 8, should
it become damaged.
As shown in Figure 3, the reaction rail 8 is secured to an
up-side down U-shaped extension 32 of the reaction rail
supporting section 18 via the fastening arrangement 20.
The fastening arrangement 20 ccmprises a screw 26, a nut
28 and a plurality of shims 30. The plurality of shims 30
can be used in order to adj ust the height of the reaction
rail 8 in relation to the elongated body 14 of the cross-
tie 10, and thus in relation to the running rails 6. In a
non-limiting example of implementation, the shims can be
of 1mm widths, 2mm widths, 5mm widths, and 20mm widths
such that by inserting or removing different shims, the
appropriate height of the reaction rail 8 can be attained.
Once the appropriate combination of shims has been
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determined by the person installing the reaction rail 8,
the reaction rail 8 is fastened securely to the cross-tie
by tightening the nut 28 and screw 26. As shown, the
screw 26 extends through the back iron 22 of the reaction
5 rail 8 in order to secure the reaction rail 8 to the U-
shaped extension 32 of the reaction raz.l supporting
section 28.
Referring back to Figure 2, each running rail supporting
10 section 16 is adapted to support a respective running rail
6. As shown, each running rail supporting section 16
includes an upper surface 34 and a lower surface 36. As
used herein, the lower surface 36 is the surface adapted
for facing the concrete guideway 4, and the upper surface
34 is the surface adapted for facing a running rail 6
supported thereon.
Traditionally, the running rail supporting sections of
prior art cross-ties have angled upper surfaces, such that
the running rails secured thereto are positioned at a
slight angle in relation to the reaction rail. A
deficiency with such prior art cross-ties is that it is
difficult to manufacture the angle of the upper surface to
the tight tolerances required, which results in a high
rate of discarded pieces.
As shown in Figure 2, the upper surface 34 and the lower
surface 36 of the cross-tie 10 are substantially parallel
to one another, thereby simplifying manufacturing. As
such, in order to position the running rails 6 at an angle
of inclination in relation to the reaction rail 8, angled
wedge members 38 are posit--oned between the upper surface
34 of the running rail supporting section 16 and each
running rail 6. The wedge members 38 can theoretically
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form angles of inclination between 0 and 90 degrees, but
more practically, this angle is typically between 0 and 3
degrees.
5 Depending on the railway track requirements, the running
rails 6 may need to be positioned at different angles of
inclination in relation to the guideway 4. As such,
instead of using a different cross-tie having a different
angle of inclination, each time a different angle of
10 inclination is required, the same cross-tie can be used,
only with a different wedge member 38. As such, regardless
of the desired angle of inclination of the running rails
6, the same cross-tie 10 can be used by simply using a
wedge member 38 raving the desired angle of inclination.
kith traditional cross-ties, a different model of cross-
tie for each different angle of inclination needed to be
manufactured, which is far more costly than simply
manufacturing wedge members having different angles of
inclination. Also, along a length of the same track, the
angle may vary from one track section to another.
Therefore, ~ using different wedge members 38 having
intermediate angles of inclination provides a smooth
transition from a first track section to a second track
section.
In a non-limiting example of implementation, the wedge
members 38 are made of an electrically insulating
material, such as nylon, therefore providing electric
insulation between the running rails 6 and the elongated
body 14 of the cross-tie 10.
In the non-limiting embodiment shown in Figure 2, the
running rails 6 are secured to their respective running
rail supporting sections 16 via a pair of rail clips 40.
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~l
It should, however, be understood that the running rails 6
can be secured to the running rail supporting sections 16
via any other securemert device known in the art.
Shown in Figure 4 is an expanded view of the running rail
6 shown in circle B of Figure 2. Referring now to Figure
4, in the non-limiting embodiment shown, the running rail
6 is secured to the running rail supporting section 16 of
the cross-tie 10 via rail cl,'_ps 40. In addition, the wedge
member 38 is secured in place by being sandwiched between
the upper surface 34 of the running rail supporting
section 16, and the running rail 6.
The rail clips 40 used are standard e-clipsTM from Pandrol.
The rail clips 40 secure the running rail 6 to the running
rail. supporting section 16 of the cross-tie 10. Rail clips
40, such as the ones shown in Figures 2 and 4, are well
known in the art, and as such will not be discussed in
further detail herein.
In a non-limiting example of implementat:Lon, the rail
clips 40 are also electrically insulated. For example,
they can be made of an electrically insulating material
such as nylon. Therefore, between the electrically
insulating wedge members 38, and the electrically
insulating rail clips 40, the running rails 6 are
completely electrical insulated from the elongated body 14
of the cross-tie 10.
Referring back to Figure 2, in the non-limit ing embodiment
shown, the cross-tie 10 is adapted to be secured to the
guideway 4 of the railway track 2 with stud-assemblies 44.
It should, however, be understood that the cross-tie 10
can be secured to the guid.eway 4 of the railway track 2,
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via any other fastening assembly known in the art.
In the embodiment shown, the stud assemblies 44 are
adapted to extend through holes in the running rail
supporting sections 16, such that they can extend into
insulating inserts 54 which are cast in the concrete
guideway 4. In the non-limiting embodiment shown in Figure
2, the cross-tie i0 is secured to the guideway 4 with one
stud assembly 44 connected through each of the two running
rail supporting sections 16, for a total of two stud
assemblies 44 per cross-tie 10. Shown in Figure 5 is an
expanded view of the stud assembly 9:4 shown in circle C in
Figure 2.
Referring now to Figure 5, the stud assembly 44 comprises
a stud 46, a lock nut 48, a coil spring 50 and an
insulating insert 54. The insulating insert 54 is adapted
to have a tight fit with the stud 46 in order to prevent
water from infiltrating between the stud 46 and the
insulating insert 54 and causing corrosion. In addition,
the insulating insert 54 includes self-locking threads 56
that require a larger amount of torque to remove the stud
46, than to insert the stud 46. The insulating insert 54
is able to retain its self-locking properties even after
the stud 46 has been removed, such that it can be re-used
many times.
The insulating inserts 54 for mounting the cross-tie 10 to
the guideway 4 of the railway track 2, enable the cross-
tie 10 to be electrically insulated from the guideway 4.
This prevents stray current from being transmitted into
the concrete guideway 4. In addition, the insulating
inserts 54 prevent galvanic corrosion of the studs 46.
Furthermore, the inserts 54 placed in the concrete
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guideway 4 do not constitute a safety hazard, as they are
flush with the guideway 4 surface. In prior art cross-
ties, studs similar to studs 46 would be cast directly in
the concrete of guideway 4. Hence, during construction of
the guideway 4 and before any cross-tie was installed, a
field of studs 4~ would stick out o:E the guideway 4, such
that they would often get bent or damaged. In addition,
construction workers could trip on the studs, or even
worse, fall on them, and get seriously hurt. In accordance
with the present design, the studs 46 are only inserted
into the insulating inserts 54 at the same time that the
cross-ties 10 are installed. As such, there is not a field
of studs sticking out of the guideway 4 prior to
installation of the cross-ties 10.
Referring back to Figure 2, in the non-limiting embodiment
shown, positioned between the lower surface 36 of the
running rail supporting sections 16, and the guideway 4 of
the railway track are elastomeric pads 58. These
elastomeric pads 58 help reduce the amount of vibration
transferred from the railway vehicle to the rail guideway
4, thereby increasing the travelers' comfort and reducing
the amount of noise venerated. In addition, in combination
with the electrically insulated stud assemblies 44, the
elastomeric pads 58 help to electrically insulate the
cross-tie 10 from the concrete guideway 4.
The cross-tie 10 is biased toward the elastomeric pads 58
via the coil springs 50 of the stud assemb:Lies 44. As the
nut 48 is threaded onto the stud 46 the coil spring 50
compresses, thereby providing the required bias of the
cross-tie 10 against the elastomeri_c pads 58.
As further shown in Figure 2, the cross-tie 10 in
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accordance with a non-limiting embodiment of the present
invention is further operative to support at least one
power rail 12, at least one derailment guard rail 60 and
an ATC (Automatic Train Control) cable support 62. Each of
these will be discussed in more deta~_1 below.
As shown in Figure 2, the cross-tie 10 in accordance with
the present invention includes a power rail supporting
section 64 which enables a power rail support 66 to be
connected to the cross-tie 10. As shown, the power rail
support 66 is connected to the power rail supporting
section 64 via two bolts 70. It should be understood that
more or less bolts could be used without departing from
the spirit of the invention. In addition, any other means
of securing the power rail support 66 to the power rail
supporting section 64 could be used. without departing from
the spirit of the invention.
The power rail support 66 is operative for carrying the
power rails 12, such that the power rails 12 can be
connected to the cross-tie 10. As shown, the power rails
12 are connected to the power rail support 66 via bolts
68. Although the power rails 12 are each supported to the
power rail support 66 via a single bolt 68, it should be
understood that more or less bolts could be used without
departing from the spirit of the invention. In addition,
any other means of securing the power rails 12 to the
power rail support 66 could be used without departing from
the spirit of the invention.
In the specific embodiment shown in the Figures, the power
rail supporting section 64 is located on the left hand
side of the cross-tie 10, and is substantially
perpendicular to the ground. It should be understood,
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however, that many other configurations for the power rail
supporting section 64 can be used without departing from
the spirit of the invention.
In addition, although Figure 2 shows the cross-tie 10 and
the power rail support 66 as being separate parts, it
should be understood that in an alternative example of
implementation, the cross-tie 10 and the power rail
support 66 can be integrally formed as one continuous
l0 piece. In such an embodiment, the power rail support 66 is
the power rail supporting section 64.
As mentioned in the background of the invention, the power
rails of traditional railway tracks for LIM rail vehicles
are connected directly to the concrete guideway of the
track. As such, the power rails and the cross-ties are not
connected in any way. A deficiency with such railway
tracks is that if there is any movement, or deformation of
the cross-ties, or of the structure supporting the power
rails, them the positioning of the power rails in relation
to the running rails and the reaction rail will change.
This could negatively impact a railway vehicle°s ability
to travel cver the railway track 2. A further deficiency
with such prior art railway tracks is that when the power
rail is bolted directly on the guideway 4, stray current
could flow in the guideway, prematurely deteriorating it.
In addition, the loss of current i.s expen~>ive for the
companies operating the railway track.
A benefit of having the power rails 12 supported by the
cross-ties 10 is that the position of the power rails 12
in relation to the running rails 6 and the reaction rail 8
is more easily controlled than if the power rails 12 were
connected directly to the concrete guideway 4. As such,
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the cross-tie 10 in accordance with the present invention
is exposed to less variation in t:he relative position
between the power rails 12 and the running rails 6 and
reaction rail 8.
In a specific, non-limiting example of implementation, the
position of power rails 12 should not vary by more than
0.25 inch (6.4 mm) both laterally and vertically with
respect to the running rails 6. When the power rails 12
are directly installed on the guideway 2, meeting this
tight tolerance requires much adjustment. l~Iowever, with
the power rails 1.2 connected directly to the cross-tie 10,
the 0.25 inch tolerance can be more easily and more
accurately achieved, by appropriate:!y dimensioning parts
and by appropriately manufacturing the same parts.
In the non-limiting embodiment shown, the vertical
position and the lateral position of the power rails 12
can be adjusted independently with respect to the cross-
tie 10. For example, the vertical position can be adjusted
via vertical slots in the portion of the power rail
support 66 that mates with the power rail supporting
section 64. Alternatively, the vertical slots could be in
the power rai-1 supporting section 64. The lateral
adjustment of the power rails 12 in relation to the cross-
tie 10 may be made through the use of shims (not shown)
that can be positioned in between the power rail
supporting section 64 and the power rail support 66, or
alternatively by adequately positioning power rail 12
using the nuts on bolts 68. However, if manufacturing
tolerances are met, it is well possible that no adjustment
be required.
The fact that the cross-tie 10 supports the power rails 12
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provides an advantage in that fewer fasteners are required
to connect the cross-tie 10 and the power rails 12 to the
guideway 4. This results in a shorter assembly time and
lower installation costs. Another advantage is that the
insulated insert 54 of the stud assemblies 44 provides an
electrically insulated system for the power rails 12.
Although the railway track 2 shown in the Figures shows
two power rails 12, it should be understood that the
railway track 2 could have included only a single power
rail 12. In the field of railway tracks 2 for LIM rail
vehicles, there are two types of power rail arrangements
that can be used. The first type of power rail arrangement
includes only one power rail, called the "third rail", and
the second type of power rail arrangement includes two
power rails, called a "fourth rail".
The second type of power rail arrangement (i.e. the one
with two power rails 12) has one positive rail and one
negative rail, while the first type of_ power rail
arrangement (i.e. the one with only one power rail 12),
uses the power rail 12 as the positive rail, and uses one
of the running rails 6 as the negative return path. The
first type of power rail arrangement is the most commonly
used, due to the fact that it saves the expense of adding
a second power rail 12. However, in order to use the
running rail 6 as the negative return path, the running
rail 6 must be well insulated from the concrete guideway
4, in order to avoid the loss of current.
In general, cross-ties in accordance with the prior art
are not electrically insulated from the concrete guideway
4, and as such, should they be operative t o support a
power rail 12, they would be restricted to being used in
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the cases where the railway track 2 uses a power rail
arrangement with two power rails.
As such, an advantage of the cross--tie 10 of the present
invention is that due to the fact that the elongated body
14 is electrically insulated from the guideway 4, via the
insulating insert 54 and the elastom.eric pad 58, the cross
tie 10 is operative to support pc>wer rail arrangements
having either one power rail, or two power rails. In
addition, the power rails 12 benefit from the fact that
the running rails 6 are electrically insulated from the
cross-tie via the insulating rail clips 40 and the
insulating wedge members 38.
As described above, the cross-tie 10 of the present
invention includes an A'IC (Automatic Train Control) cable
support 62. The ATC cable support 62 is positioned on the
reaction rail supporting section 18 of the cross-tie 10,
and includes a clamp for preventing the A~~'C cable from
moving around. The ATC cable support 30 ca:n include any
type of clamp or securing device known in the art that is
suitable for preventing the ATC cable from moving around.
Typically, the ATC cable should be located approximately 1
inch below the top of the running rails 6. A sensor on
the train then -receives a signal from the ATC cable as it
travels along the track. In prior ~:rt railway tracks, the
ATC cable is fixed to the top of an L-shaped bracket,
about 4 inches high to bring the cable to approximately 1
inch below the top of the running :rails. These brackets
are screwed directly to the guideway. In accordance with
the present invention, the ATC cable sits at approximately
2 inches below the top of the running rails 6, which is
lower than the conventional 1 inch, but still enables the
sensor on the train to receive a strong signal from the
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ATC cable. The fact that the A'7,C cable is supported
directly on the cross-tie 10 avoids having to use an
additional bracket, which saves costs, materials, and
installation time.
As further described above, the cross-tie 10 in accordance
with the present invention is operative to support at
least one derailment guard rail 60. In the specific
embodiment shown in Figure 2, the cross-tie 10 has two
derailment guard rails 60 attached thereto, namely one on
each side of the reaction rail supporting section 18. As
shown, each derailment guard rail 60 is connected to
cross-tie 10 via a bolt 72 that extends through the
derailment guard rail 60 and secures it to the respective
t5 upper portion of each running rail supporting section 16.
Derailment guard rails 60 are known in the art and as such
will not be described in more detail herein.
In order to create a railway track 2 for an LIM rail
vehicle, such as the one shown in Figure 1, a plurality of
cross-ties 10 in accordance with the present invention are
positioned across the concrete guideway 4. In a non
limiting embodiment, the cross-ties 10 are mounted to the
concrete guideway 4, such that there is one cross-tie 10
approximately every 1 meter.
As shown in Figure 1; although each cross-tie 10 includes
a power rail supporting section 64, only one out of every
three cross-ties ~_0 has a power rail support 66 connected
thereto. It should, however, be understood that a power
rail support 66 can be connected to every cross-tie 10, or
more frequently or less frequently than every third cross-
tie 10.
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ZV
Once the cross-ties 10 are mounted to the concrete
guideway 4, the running rails 6, reaction rail 8 and power
rails 12 are mounted thereto. In general, the reaction
rail 8 is formed in sections that are between 3m and 10m
long. As shown in Figure 6, the sections of reaction rail
8 are attached to the reaction rail supporting sections 18
such that there is a gap 75 between subsequent portions of
the reaction rail 8.
l0 As described above, the cross-tie 10 of the present
invention is operative to support the running rails 6, the
-reaction rail 8 and one or more power rails 12, as an
integrated assembly. Cross-ties 10 in accordance with the
present invention, enable a relatively high stiffness of
the assembly to maintain the tight tolerance required in
the height of the air-gap between the reaction rail 8 and
the vehicle mounted LIM, and enable a relatively low
stiffness in the cross-tie 10/guideway 4 interface to
ensure an acceptable ride quality, wheel/rail interaction
and vibration isolation. Since the running rails 6 and the
reaction rail 8 are both supported by the cross-tie the
relative deflection between them under operating
conditions will be limited, and will be .independent of
deflection of the cross-tie which is mounted on
elastomeric pads tc the guideway.
Although various embodiments have been illustrated, this
was for the purpose of describing, but not limiting, the
invention. Various modifications will become apparent to
those skilled in the art and are within the scope of this
invention, which is defined more particularly by the
attached claims.
