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This invention relates to the constructions of
trackside platforms for railways, tramways or the like.
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Strict safety rules are enforced for the safety of
persons involved in construction work at the trackside of
a railway. For example, when work is undertaken very
close to a railway track, a barrier is erected to prevent
access to the track and all traffic on the track is
stopped during the work. Stopping all traffic on the
track, however, represents a financial loss to the
company using the track and therefore it is important
that the time for which all traffic is stopped should be
kept low.
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On the other hand, when a trackside platform is
being constructed, the workers have to work close to the
track because that is the very position in which it is
desired to place the platform.
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It is an object of the invention to provide a method
of constructing a trackside platform which reduces the
need to stop all traffic on the adjacent track for an
extended period.
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The present invention provides a method of
constructing a trackside platform for a railway, a
tramway or the like, comprising:
- providing blocks of expanded polystyrene at the
trackside in a configuration corresponding generally to
the shape and position of the platform to be constructed;
and
- surfacing the top and sides of the polystyrene
blocks in stronger, more durable material.
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Such a method has the advantage that because
expanded polystyrene is a very light material used in a
pre-fabricated form it is very quickly and easily laid in
position so that construction work can proceed rapidly.
In contrast, the construction of a trackside platform
entirely in a conventional building material such as
concrete would take much longer to accomplish. Thus, the
invention enables work to proceed more quickly, so
reducing the time for which traffic has to be stopped on
the track. A further advantage of the invention is that
it is relatively easy to dismantle the platform so
constructed, should it be decided that it is no longer
required. Yet another advantage is that the lightness of
the construction enables the platform to be built on land
of low load-bearing capacity.
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Preferably, the top and sides of the blocks are
surfaced using concrete. That provides a relatively
inexpensive construction.
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Advantageously, the method comprises using only pre-fabricated
components for parts of the platform within a
predetermined distance of the nearest rail and fitting
the said pre-fabricated parts whilst stopping traffic on
the track. By this means, traffic is stopped for the
operations requiring the workers to be closest to the
track and the use of pre-fabricated components keeps the
time for which traffic is stopped relatively short.
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The method may include applying surfacing material
to the top of the expanded polystyrene blocks at
locations further than a predetermined distance from the
nearest rail whilst permitting traffic on the track but
preventing access thereto by construction workers by
means of a barrier. By this means, for much of the
construction, work can proceed without stopping traffic
on the track.
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The method may include preparing the ground for the
blocks, and laying the blocks whilst permitting traffic
on the track but preventing access thereto by
construction workers by means of a barrier at a
predetermined distance from the nearest rail. Again,
much of the construction work can proceed without
stopping traffic on the track.
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The step of preparing the ground may include
preparing a formation level. That provides a simple,
quick and relatively inexpensive foundation for the
blocks.
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It is preferred that the predetermined distance be 4
feet (1220 millimetres). This distance gives an adequate
level of safety, enables the platform to be placed
sufficiently close to the track, and yet allows work to
proceed whilst keeping the interruption to traffic low.
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The method may include fitting cantilevered coping
members to the or each trackward edge of the blocks to
provide a safety recess under the platform edge. Such
members are readily available commercially.
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The method preferably includes using a recess
provided at the top of the or each trackward edge of the
blocks to accommodate an inner edge portion of the coping
members. Such a construction facilitates the fitting of
the coping members.
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The method may include casting surfacing material in
situ on the top of the said blocks. Such a step is
simple and relatively inexpensive. A further, hard
wearing, layer of material, such as asphalt, may be
provided on top of the cast layer if desired.
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The surfacing material may be fibre-mesh reinforced
concrete. Such material is both strong and relatively
inexpensive.
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Preferably, a geomembrane is provided between the
said blocks and the surfacing material. Such a membrane
helps prevent damage from chemical spillage and can, when
a suitable material is used, provide a measure of fire
protection.
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Advantageously, the method includes attaching metal
brackets to the surfacing material and using the brackets
for fixing components on the or each trackside edge of
the blocks. Brackets enable the trackside components to
be fixed relatively quickly so keeping low the disruption
to traffic on the adjacent track.
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The method may include fixing the brackets to the
surfacing material by means of bolts. The bolts may be
embedded in the above-mentioned layer cast in situ and
provide a particularly simple means of fixing the
brackets.
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Advantageously, the method includes using each metal
bracket to fix both a facing component and a coping
component. Such a construction is particularly
economical.
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The method may include using facing components in
the form of inter-locking facing panels on the or each
trackward side of the blocks. The inter-locking panels
provide a weatherproof surface for the blocks.
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The method may include using spaced-apart facing
posts on the or each trackward side of the blocks and
sliding facing panels, interlocking with the posts into
the spaces between the posts. The sliding in of the
panels is quickly accomplished and may take place
sufficiently far from the nearest rail for traffic to be
allowed on the track while the panels are being
positioned. The panels may be pre-cast concrete planks.
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Instead, facing components may be fixed to the two
opposite sides of the blocks by means of fixing rods
passing through the blocks. In this construction, no
brackets are required for fixing the facing components.
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The invention is applicable to a platform
constructed at a location where there is an adjacent
track on only one side or to a platform constructed at a
location with an adjacent track on each side.
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The invention also provides a trackside platform
constructed by a method according to the invention.
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In particular, the platform may be a railway
platform.
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The construction of trackside platforms in
accordance with the invention will now be described, by
way of example only, with reference to the accompanying
drawings, in which:
- Figure 1 illustrates diagrammatically the use of a
first set of safety regulations;
- Figure 2 illustrates diagrammatically the use of a
second set of safety regulations;
- Figures 3A to 3E show steps in a first method of
constructing a trackside platform according to the
invention;
- Figure 3F shows a detail of the construction of the
first method;
- Figure 3G shows a typical cross-section through the
construction of the first method;
- Figures 4A to 4D show steps in a second method of
constructing a trackside platform according to the
invention;
- Figure 4E shows a detail of the construction of the
second method; and
- Figure 4F shows a typical cross-section through the
construction of the second method.
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Referring to the accompanying drawings, methods of
constructing a platform at a location where there is an
adjacent track on only one side will now be described.
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The use of a first set of safety regulations termed
"safe system of work type A" is illustrated in Figure 1.
Two adjacent railway tracks 2 and 4 are shown and a
construction site 6. A site fence 8 is erected between
the tracks 2, 4 and the construction site 6 to provide a
barrier between construction workers 10 and the railway
tracks 2 and 4. The fence 8 is spaced a predetermined
distance d from the nearest rail 12, d being four feet
(1220 millimetres). On the closer track 2 to the
construction site 6, traffic is permitted to move at a
speed of forty miles per hour or less. On the more
distant track 4, no speed restriction is imposed.
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A second set of safety regulations termed "safe
system of work type B" is illustrated in Figure 2 which
corresponds generally to Figure 1 except that the site
fence 8 is replaced by a site fence 8' located between
the tracks 2 and 4 and spaced a distance d', either four
feet (1220 millimetres) or six feet six inches (2000
millimetres) from the nearest rail 14 of the track 4. No
traffic is permitted on the track 2. On track 4, traffic
is restricted to a speed of forty miles per hour or less
if d' is four feet (1220 millimetres0 and no speed
restriction is imposed if d' is six feet six inches (2000
millimetres).
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Figure 3A shows a first step in a first method
according to the invention. Under safe system of work
type A, a formation level 20, for example, based on sand
with the addition of some cement, is prepared close to
the site fence within the safe fenced area and blocks of
expanded polystyrene 22 are laid on the prepared
formation level 20 at the trackside in a configuration
corresponding generally to the shape and position of the
platform to be constructed. Only one such block is shown
in the drawings, further blocks are added in line
according to the length of platform required, the end
blocks sloping away to ground level in the usual manner
for a trackside platform.
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Figure 3B shows the second step in which, under safe
system of work type A, a protective geomembrane 24 is
applied to the blocks 22 and a glass fibre reinforced
concrete slab 26 is cast in situ on the top of the blocks
22. The slab 26 includes additional steel reinforcement
(not shown) and bolts (not shown) for fastening brackets
to the described shortly.
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Figure 3C shows the third step in which, under safe
system of work type B, steel support brackets 28 and
slotted concrete posts 30 are installed on the trackward
side of the platform.
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Figure 3D shows the fourth step in which, under safe
system of work type A, pre-cast concrete facing panels 32
are slid into position in grooves in the posts 30.
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Figure 3E shows the fifth and sixth steps in which,
under safe system of work type B, coping stones 34 are
mounted on the brackets 28 in a recess 36 provided in the
trackward edge of the blocks 20. Under safe system of
work type A, a hot rolled asphalt wearing course 38, for
example, an asphalt or concrete finish, is provided on
the top surface of the platform.
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The remaining side of the platform is faced with
concrete either cast in situ or applied as pre-fabricated
panels (not shown). The ends of the platform are treated
similarly.
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Figure 4A shows a first step in second method
according to the invention. Under safe system of work
type A, a formation level 40, for example, based on sand
with the addition of some cement, is prepared close to
the site fence within the safe fenced area and blocks of
expanded polystyrene 42 are laid on the prepared
formation level 40 at the trackside in a configuration
corresponding generally to the shape and position of the
platform to be constructed. Only one such block is shown
in the drawings, further blocks are added in line
according to the length of platform required, the end
blocks sloping away to ground level in the usual manner
for a trackside platform.
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Figure 4B shows the second step in which, under safe
system of work type A, a protective geomembrane 44 is
applied to the blocks 42 and a glass fibre reinforced
concrete slab 46 is cast in situ on the top of the blocks
42. The slab 46 includes additional steel reinforcement
(not shown) and bolts (not shown) for fastening brackets
to the described shortly.
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Figure 4C shows the third step in which, under safe
system of work type B, steel support brackets 48 and
interlocking pre-cast concrete panels 50 are installed on
the trackward side of the platform.
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Figure 4D shows the fourth and fifth steps in which,
under safe system of work type B,
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Figure 3E shows the fifth and sixth steps in which,
under safe system of work type A, coping stones 54 are
mounted on the brackets 48 in a recess 56 provided in the
trackward edge of the blocks 40. A hot rolled asphalt
wearing course 58 is provided on the top surface of the
platform.
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The remaining side of the platform is faced with
concrete either cast in situ or applied as pre-fabricated
panels (not shown). The ends of the platform are treated
similarly.
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Some typical dimensions are given below by way of
example:
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Position of the platform edge relative to the
nearest running rail: 730 to 771 millimetres horizontally
and 915 metres vertically.
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Refuge space under the platform edge: at least 300
millimetres wide and 480 millimetres high for the full
length of the platform.
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Concrete slab cast in situ: 200 millimetre thick
class C30 concrete.
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Coping stones: 394 to 435 millimetres overlying the
platform, 479 to 520 millimetres overhanging the platform
edge.
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If the platform is to be constructed as an island
platform between two tracks, coping stones would be
provided on both sides.
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Instead of concrete, a known asbestos substitute
could be used for facing the sides of the platform.
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The invention is applicable to many different sorts
of trackside platform including tramways and overground
sections of an underground railway.
