METHOD FOR PRECASTING TRACK SUPPORT SLEEPERS ON A
PRECAST SPAN
This invention relates to a method of precasting
track support sleepers, in particular on a precast
structure for delimiting tracks, such as full precast
U-shaped spans used during the realisation of railway
viaducts. It also relates to a method for laying rails
on a span equipped with precast sleepers.
A method for laying rails on precast spans is
known. According to this method, in a first step,
carried out are the installation of the main points
representing the axis of the track installed in the
span, then that of the secondary points and the
realisation of the rejection pegging out, in a second
step the rails are supplied then welded and provided
with their means of fastening to the span, in a third
step adjusting gauges are set in place and the provided
rails are prepositioned on the latter, in a fourth step,
the armouring of the sleepers are set into place, the
track is adjusted, the formwork is realised and the
concrete is poured, and in a fifth step, the track is
again verified and the formwork is removed.

Such a method, although it does meet the
requirements in terms of civil engineering, is rather
inconvenient due to the fact that the substantial
concreting of the sleepers is performed on site, which,
in particular, takes up a considerable amount; of time,
and is subject to the scheduling constraints concerning
the project as a whole, and imposes constraints on the
project.
This invention aims to realise a new method making
it possible to overcome the aforementioned
disadvantages.
The invention as such includes a method of
precasting track support sleepers on a precast span,
including a step of positioning the track during which
dummy rails having the same profile as those to be
installed on site are arranged on the span in
accordance with the position of the final rails, a step
of setting up re-entrants of systems of fastening rails
to the span during which are fixed to the rails, to the
positions of the systems of fastening, re-entrant
moulds with dimensions corresponding to those of the
systems of fastening, and a step of realising sleepers
during which the armouring of the sleepers are set into
place, the formwork is carried out and the concrete is
poured.
The main advantage of such a method is that it can
be carried out in the factory. As such, the conditions
for implementing concrete are clearly more favourable:
climatic influences are reduced, and even suppressed;
the concrete is made on the site, which suppresses
transit time, and reduces, and even suppresses, the use

of additives such as retarders or fluidifiers (for the
pumping) ; the control of quality is improved due to the
very fact of being carried out in the factory. In
addition, the realisation of sleepers is disconnected
from the progress of the project, which makes it
possible to remove the construction of the track
support sleepers from the critical path of the
realisation of the project in relation to a
conventional method of realisation.
The invention also includes a method for laying
rails on a span equipped with precast sleepers,
including a step of setting up rails during which the
rails, provided with systems of fastening, are
correctly arranged in relation to the span, and a step
of sealing during which the systems of fastening of the
rails are sealed to the span by concreting in the re-
entrants made in the sleepers.
As such, the works on the site are greatly
simplified, resulting in substantial savings in
scheduling in the placing of track and over the entire
project. In addition, it is still possible to adjust,
on site, the placing of the tracks of great length, and,
as required, to concrete the track once the rails have
been adjusted.
Finally, the two methods make it possible to
reduce the cost of realising the track in concrete (in
linear metres).
The invention also relates to a method of setting
up, on site, rails on precast spans, including a first
step of precasting, more preferably in the factory, of
sleepers on the precast spans, followed by a second

step, on site, of placing rails on the span provided
with precast sleepers.
Other particularities and advantages of this
invention shall appear in the embodiment provided by
way of a non-limited example and shown in the annexed
drawings wherein:
Figure 1 is a schematic cross-section view of a
precast span;
Figure 2 is a view similar to figure 1, of the
dummy rails being arranged in accordance with the
positions of the corresponding final rails on site;
Figure 3 is a schematic cross-section view, of a
dummy rail provided with a re-entrant mould and set in
place in the formwork of a sleeper;
Figure 4 is a schematic top view corresponding to
figure 3;
Figure 5 is a view similar to figure 3, after form
removal and removal of the dummy rail;
Figure 6 is a schematic top view corresponding to
figure 5;
Figure 7 is a schematic cross-section view of a
span provided with precast sleepers, with the final
rails being correctly positioned;
Figure 8 is a schematic cross-section view, of a
final rail provided with a system of fastening which is
set in place in a re-entrant of a sleeper;
Figure 9 is a view similar to figure 8 after
sealing of the system of fastening to the sleeper.
Generally, the general process of placing rails 1
on a precast span 2 includes a method of precasting
track support sleepers 3 on a precast span 2, followed,

on site, by a method of fastening rails 1 on the span 2
provided with sleepers 3, realised in accordance with
the aforementioned method.
The method of precasting sleepers 3 is carried out,
more preferably, in the factory due to the many
advantages that are inherent to the technical
possibilities available in the factory. It could
however be carried out, as required, on site, the
precasting of the sleepers 3 however being realised
before the setting in place of the span on its site
dedicated to it.
The method of precasting is particularly adapted
to the spans 2 used for the realisation of railway
viaducts, in particular to full spans (extending from
one pier to the other of the viaduct), self-supporting
and U-shaped.
This method includes a step of layout drawing.
During this step a layout drawing of the span 2 as well
as of the joints from the span to the abutments is
carried out. This layout drawing that is proper to each
span in question (carried out, for example, on a A3-
format sheet) comprises an outline sketch of the span,
with the joints to the abutments, rails 3, positions of
the systems of fastening of rail 4, as well as various
particular equipment concerning this span, such as a
cable crossing. It also comprises the indications of
horizontal, profile in length and elevation alignment.
This layout drawing makes it possible to know the exact
position of each rail 1 and of each system of fastening
of rail 4, and makes it possible to adapt the sleeper-

spacing, as required, to the joints, for the span 2 in
question.
The method also includes a step of installing the
track on the span 2. During this step fixed markings
are installed on the span 2 (in the concrete of the
span 2) . These markings materialise the axis of the
track. More preferably, at each span three markings are
made: one at each end and one at the cent
advantageous that these markings be installed during
the precasting of the span 2 itself.
The method includes a step of positioning the
track. During this step, dummy rails 5 that have the
same profile as those 1 that will be placed on site on
this span 2, are arranged on the span 2. The dummy
rails 5 are installed on adjusting gauges 6 that make
it possible to arrange them in accordance with the
position of the final rails. This step is carried out
thanks, on the one hand, to the layout drawing that was
made beforehand, and, on the other hand, to the
markings that were installed beforehand on the span 2.
The method further comprises a step of setting up
a re-entrant 7 of the systems of fastening 4 of the
rails 1 to the span 2 (cf. figure 2). During this step,
re-entrant moulds 8 are fixed to the dummy rails 5 (cf.
figures 3 and 4). This step, as the step of positioning
the track, is carried out thanks to the layout drawing
and to the markings on the span 2. It makes it possible
to leave free of concrete the zones of the sleeper 3
where the systems of fastening 4 of the rails 1 will be
located on site. As such, the re-entrant moulds 8 have
dimensions that correspond to those of the systems of

fastening 4 used on site, and they are arranged in the
positions provided in these systems 4 . Drawing
inspiration from the conventional process of setting up
systems of fastening of rails on site, in the curves
and connections of a horizontal alignment, in a first
step, the re-entrant moulds 8 are fixed to the dummy
rail 5 of large radius with the spacing of the sleeper-
spacing nominal, and in a second step, the re-entrant
moulds are fixed to the dummy rail 5 of small radius by
perpendicularity in relation to those fixed to the
dummy rail of large radius.
In this embodiment the system of fastening 4 used
is a system with tie-plate 9: the rail 1 is fixed to
the tie-plate 9 (here, by screws 10), and the tie-plate
9 is fixed to the sleeper 3 (here, by sealing rod 11).
More precisely, in this example, the system of
fastening 4 is the Vossloh system (Vossloh tie-plate
336). Therefore, the dimensions of the re-entrant mould
8 are imposed by those of this system 4. A Vossloh tie-
plate 336 measures 390 mm in width and 160 mm in length.
Moreover, the length of the sealing rods 11 must also
be taken into account as well as their maximal possible
inclination which is defined according to the maximal
elevation. As such, for a maximal elevation of 120 mm
(8.36% for an UIC gauge of 1435 mm), it is necessary to
integrate, on either side of the tie-plate 9, a
widening of 9.6 mm (rounded to 10 mm).
More preferably, the dimensions of the moulds 8
used take into account the tolerances making it
possible to adjust the placing of the rails 1
longitudinally, transversally and vertically, in order

to recover from any shifts that could take place when
placing the span 2.
The longitudinal tolerance includes, other than a
tolerance linked to the position of the system of
fastening 4 in relation to the span 2 (here, of a value
of one inch or 25 mm) , a tolerance linked to the
longitudinal position of the span 2 due to the
dimension of the joint between two spans 2 (here, of a
value of 10 mm). In this example, the dimensions of the
mould 8 make it possible to accept a shift of 35 mm in
the placing of the system of fastening 4 in one
direction as in the other. Therefore the longitudinal
dimension of the mould 8 is 230 mm (length of the tie-
plate 9 plus twice the longitudinal tolerance).
The transversal tolerance concerns the horizontal
shift of the placing of the ends of spans 2 in relation
to the theoretical axis of the track. It includes,
other than a tolerance linked to the position of the
system of fastening 4 in relation to the span 2 (here,
of a value of one inch or 25 mm), a tolerance linked to
the placing of the track (here, of a value of 5 mm). In
this example, the dimensions of the mould 8 make it
possible to accept a shift of 30 mm in placing the
system of fastening in one direction as in the other.
Therefore the transversal dimension of the mould 8 is
470 mm (width of the tie-plate 9 plus twice the
widening plus twice the tolerance).
The vertical tolerance concerns the difference in
altitude of the ends of span 2. In this example, the
value of the free passage between the finished level of
concrete and the bottom of the rail (45 mm in the case

of the Vossloh tie-plate 336) cannot be decreased since
this would result in an impossibility of installing the
adjusting gauges 6 for placing the track on site. As
such, in this example, by considering a tolerance of
one inch or 25 mm, the vertical tolerance is 0 in one
direction and - 25 mm in the other.
The method of precasting further comprises a step
of verifying the adjustment of the track at the end of
span 2. In order to carry out an adjustment of the
rails absolutely outside of the span and to verify the
relative values of deflection, and therefore avoid
interfacing problems between spans during the placing
of the track on site, the dummy rails 5 used have
considerable travel. As such, for a span 2 of a length
of 25 m, it is preferable to use dummy rails 5 of a
minimal length of 45 m in order to have an overhang of
10 m on either side of the span 2.
The method of precasting finally includes a step
of carrying out sleepers. During this step the
armouring of the sleepers 3 are put into place, the
formwork 12 is carried out (cf. figures 3 and 4) and
the concrete is poured. The transversal and vertical
dimensions of each sleeper 3 depend on the system of
fastening of the rail 4. As such, for the Vossloh
system 336, each sleeper 3 has a minimal height of 200
mm and a minimal width of 525 mm against the tie-plate
9, for a sleeper 3 without anti-derailing measurement.
Finally, the method of precasting includes a step
of finishing during which the formwork 12, the gauges 6
and the dummy rails 5 provided with re-entrant moulds 8
are removed.

The method of fixing rails 1 on a span equipped
with precast sleepers 3 includes a step of preparing
the span 2 during which are installed the implantation
of the main points of the axis of the tracks (beginning
and end of straight alignment, of connection, of body
of curve;, of point-end joints of the track devices,
etc.) then the secondary points, and during which is
carried out the rejection pegging out serving as a
reference for the positioning of the track.
This method also includes a step of preparing
rails 1 during which the rails 1 are welded and
provided with systems of fastening 4. As traditionally
carried out during the setting in place of systems of
fastening of rails on site, in the curves and
connections of the horizontal alignment, in a first
step, the systems of fastening 4 are fixed to the rail
1 of large radius with the spacing of the sleeper-
spacing nominal, and in a second step, the systems of
fastening 4 are fixed to the rail 1 of small radius by
perpendicularity in relation to those fixed to the rail
1 of large radius.
The method includes a step of putting into place
rails 1 (cf. figure 7). During this step, the rails 1
are arranged on adjusting gauges 6 which allow them to
be arranged in accordance with the course of the track.
As required, the method can include a step of
formwork during which a formwork is realised around the
system of fastening 4 (here, around the tie-plate 9) in
order to take into account, where applicable, vertical
differences of the position of the rail 1. This
necessity is due in particular to the limits imposed on

the vertical tolerances of the dimensions of the re-
entrant moulds 8.
The method of fixing of rail 1 includes a step of
sealing during which the systems of fastening of rail 4
are sealed to the span 2 by concreting in the re-
entrants 7 made in the sleepers 3 (and possibly, where
applicable, in the formwork carried out around the
systems of fastening). Prior to sealing, a final
adjustment of the track is carried out. Once the
sealing has been carried out, the track is verified.
Finally, the method includes a step of finishing during
which the gauges 6 and any formwork are removed.
This invention is not limited to this embodiment.
It can as such be applied to other systems of fastening.
It would also be possible to apply it for the
precasting of sleepers provided with anti-derailing
measurement.

CLAIMS
1. Method of precasting track support sleepers (3)
on a precast span (2), characterised in that it
includes:
- A step of positioning the track during which
dummy rails (5) having the same profile as those (1) to
be placed on site are arranged on the span (2) in
accordance with the position of the final rails (1),
- A step of setting up re-entrants (7) of the
systems of fastening (4) of the rails (1) to the span
(2) during which re-entrant moulds (8) of dimension
corresponding to those of the systems of fastening (4)
are fixed to the dummy rails (5) , at the positions of
the systems of fastening (4), and
- A step of realising sleepers (3) during which
the armouring of the sleepers are set into place, the
formwork (12) is carried out and the concrete is poured.
2. Method of precasting sleepers set forth in
claim 1, characterised in that it includes, prior to
the step of positioning the track, a step of layout
drawing during which is carried out an outline sketch

of the span, of the rails, and of the positions of the
systems of fastening of the latter to the span.
3. Method of precasting sleepers (3) set forth in
claim 1 or 2, characterised in that it includes, prior
to the step of positioning the track, a step of
installing the track during which markings are fixed on
the span (2).
4. Method of precasting sleepers (3) according to
one of claims 1 to 3, characterised in that it includes,
prior to the step of concreting, a step of verifying
the adjustment of the track at the end of span (2)
during which the dummy rails (5) which have an overhang
in relation to the span (2), on each side of the latter,
are adjusted absolutely outside of the span (2) and
have their deflection verified.
5. Method of precasting sleepers (3) according to
one of claims 1 to 4, characterised in that it includes
a step of finishing during which are removed the
formwork (12), the gauges (6) and the dummy rails (5)
provided with re-entrant moulds (8).
6. Method for laying rails (1) on a. span (2)
provided with precast sleepers (3) comprising re-
entrants (7), characterised in that it includes:
- A step of setting up rails (1) during which the
rails (1), provided with their systems of fastening (4),
are correctly arranged in relation to the span (2), and
- A step of sealing during which the systems of
fastening (4) are sealed to the span (2) by concreting
in the re-entrants (7) made in the sleepers (3).
7. Method for laying rails (1) set forth in claim
6, characterised in that it includes, prior to the step

of setting up the rails (1), a step of welding during
which the rails (1) are welded to the rails of the
preceding span.
8. Method of placing rails (1) set forth in claim
6 or 7, characterised in that it includes, prior to the
step of fastening, a step of formwork during which a
formwork is carried out around the systems of fastening
(4) .
9. Method for laying rails (1) on a precast span
(2), characterised in that it includes the steps of the
method of precasting sleepers (3) according to one of
claims 1 to 5, a step of supplying during which the
span (2) provided with precast sleepers (3) is brought
to a project site, and the steps of the method for
laying rails (1) on the precast span provided with
precast sleepers (3) in accordance with one of claims 6 to 8.

The method includes:
- A step of positioning the track during which
dummy rails (5) having the same profile as those to be
placed on site are arranged in the span (2) in
accordance with the position of the final rails,
- A step of setting in place re-entrants of the
systems of fastening rails to the span (2) during which
re-entrant moulds (8) of dimension corresponding to
those of the systems of fastening are fixed to the
dummy rails (5), at the positions of the systems of
fastening, and
A step of realising sleepers during which the
armouring of the sleepers are set into place, the
formwork (12) is carried out and the concrete is poured.