EP1700954A2

EP1700954A2 - Prefabricated modular member, permanent railway for tramways and subways including said member, and process for laying the same

Info

Publication number: EP1700954A2
Application number: EP05028361A
Authority: EP
Inventors: Pierantonio Carnelli
Original assignee: SEAP Costruzioni Generali SpA
Current assignee: SEAP Costruzioni Generali SpA
Priority date: 2004-12-23
Filing date: 2005-12-23
Publication date: 2006-09-13
Also published as: ITMI20042465A1; EP1700954A3

Abstract

The present invention is a prefabricated modular member (1) for making a permanent way, including tracks and track equipment, comprising a reinforced concrete platform (2) having two main surfaces and one lateral peripheral surface, at least one vent-hole (3) whose ends open out of these two main surfaces, a plurality of level adjustment elements to adjust the height and inclination of the platform, at least one pair of rails (7) or special track equipment parts secured to one of the main surfaces of the platform, characterized in that it includes a plurality of first anchors (4a) at one of said main surfaces to allow lifting and handling of the platform, and in that rails or special track equipment parts are anchored to the platform by means of screws, which are held in guides (11) embedded in the platform, these guides being oriented transverse to the rails.

Description

The present invention relates to a modular permanent way including tracks and track equipment (switches and crossings) for tramways and subways and a process for laying the same.
A number of approaches are known to make permanent ways including tracks and track equipment for tramway and subway lines.
In a first prior art approach, the rails are fastened to wooden or reinforced concrete sleepers, embedded in a ballast, which in turn lies on a leveling bed of various kinds, such as natural or backfill soil.
The ballast has the purpose of distributing loads and maintaining track geometry.
This known approach has a few drawbacks.
Particularly, the ballast does not ensure track stability with time, as it tends to be subjected to gradual sagging which lead to intolerable changes in the overall track geometry.
If the permanent way is of recent construction, some maintenance, such as a new leveling step, may be sufficient.
However, if the permanent way is older, it needs overall renewal.
Renewing works on a ballasted permanent way for a tramway require relatively long times.
Removal of the paving, dismantling of the old system, excavation and trench leveling, placing of the ballast, laying of sleepers and rails and final repaving involve an estimated works duration - depending on node complexity - of at least two weeks.
The inconveniences caused by permanent way maintenance or removal are not limited to railway traffic.
The inconveniences caused by maintenance or renewal of tramway lines can only be fully understood when considering that an important portion of tracks and especially track equipment (which are mostly placed at crossings) are located on road paving (about 45% of tramway lines in Milan) and that the renewal of a tramway system obviously requires a construction site to be set up, which leads to considerable problems in road traffic.
To reduce the requirements of maintenance or renewal of the permanent track, the ballast is being replaced by more stable substructures, essentially consisting of reinforced concrete slabs, laid on a poor concrete leveling bed, with an elastomeric mat being generally interposed between the bottom bed and the slab, for vibration damping purposes.
The track or track equipment (switch or crossing) is built on such slabs, with the so-called "Milano" system, in which the rails are secured using metal plates, the latter being fastened to the slab with bolts and maintained at the design level using on site-built blocks of quartz sand and epoxy resin.
These concrete plate-mounted permanent ways exhibit an improved structural stability with time, as compared with ballasted permanent ways, whereby the requirements of maintenance of tramway permanent ways is reduced.
However, this solution also has various drawbacks.
Concrete setting times, as well as the step of securing the track to the reinforced concrete slab considerably increase the overall permanent way building time.
The replacement of a ballasted turnout (e.g. consisting of two switches and one crossing) with a concrete slab-mounted permanent way currently requires about five-six weeks.
Obviously, this increases inconveniences for normal tramway and road circulation.
As a result, building of permanent ways by using this approach is not advantageous at all.
From EP-B1-983-400 , it is known to build permanent ways from reinforced concrete prefabricated modular members, having an inverted isosceles trapezium cross-section.
Each modular member bears a rail section, which is removably secured to the modular member itself.
The modular members are laid in parallel pairs on a metal support structure, which is placed in a trench.
The support structure lies on the bottom bed by supporting screws, which allow level adjustment of the structure and the modular members supported thereby.
Tie rods are further provided to adjust the distance between the modular members, i.e. the gauge (predetermined distance between the inner edges of the track rails).
Then, the portion underlying the support structure is filled with injected concrete.
Nevertheless, this known approach also involves various problems.
The provision of separate modular platforms supporting each rail makes this arrangement unsuitable for the complex geometry of railway switches and crossings, which are characterized by special components, such as switch points and frogs, which require the platform to have a continuous cross-section and to allow a simple and linearly variable rail-platform anchorage.
Also, this laying technology is complex and laborious, and does not respond in a flexible and simple manner to road works needs, wherefore the system seems to be designed, as it requires repeated interventions to reach the final leveled height position.
Also, the design and actual construction platform has its extrados at the same height as the rail surface (rolling surface) and the road surface - as the rail is embedded therein - wherefore it does not allow to use pavements like those currently in use (bituminous pavements or granite block pavements) or new pavements complying with urban environment choices.
From DE 199 48 993 A1 , it is known to build permanent ways from reinforced concrete prefabricated modular elements, connected together by means of tie rods.
Each modular elements has bumps on one side, which act as rail supporting surfaces
The rails are anchored to such bumps by means of stirrups and bolts.
This technology also has a number of drawbacks.
Particularly, assembly of the various modules requires a very high accuracy.
The object of this invention is to obviate at least some of prior art drawbacks and particularly the drawbacks set out hereinbefore.
This object is fulfilled by a prefabricated modular member for making a permanent way, including tracks and track equipment, as defined in claim 1, by a permanent way, including tracks and track equipment, as defined in claim 13, and by a process for making a permanent way, including tracks and track equipment as defined in claim 14.
Further advantages may be achieved by the additional features of the dependent claims.
A possible embodiment of the prefabricated modular member, as claimed in the attached claims, will be described hereafter with reference to the accompanying drawings, in which:

Figure 1 is a first cross sectional view of a prefabricated modular member;
Figure 2 is a second cross sectional view of a prefabricated modular member;
Figure 3 is a transverse view of a detail of the prefabricated modular member as shown in Figure 1;
Figure 4 is a transverse of the detail of Figure 3;
Figure 5 is a view of a second detail of the prefabricated modular member as shown in Figure 1;
Figure 6 is a view of a third detail of the prefabricated modular member as shown in Figure 1;
Figure 7 is a cross sectional view of the prefabricated modular member once it has been laid;
Figure 8 is a plan view of a plurality of prefabricated modular members in laid positions;
Figure 9 is an enlargement of Figure 2, which shows the rail-platform anchorage; and
Figure 10 is an enlarged view, showing a variant of the rail-platform anchorage of Figure 9.

Referring to the annexed drawings, numeral 1 generally designates a prefabricated modular member for making a permanent way, including tracks and track equipment.
The modular member 1 includes a reinforced concrete platform 2 having two main surfaces 2a, 2b and one lateral peripheral surface 2c.
The two main surfaces 2a, 2b are preferably, but without limitation, parallel.
The thickness of this platform is preferably of 200 to 300 mm.
At least one pair of rails or special track equipment parts 7 are secured to one of the main surfaces 2b of the platform.
The rails may be either standard track rails or special rails for switches.
The modular member 1 has at least one vent-hole 3 - whose function will be better explained hereafter - whose ends open out of both main surfaces 2a, 2b.
Each vent-hole 3 has preferably a diameter of 40 to 60 mm.
For the platform 2 to be lifted and handled, a plurality of first anchors 4a are provided at one of said main surfaces 2a, 2b.
A plurality of second anchors 4b is further provided at the lateral peripheral surface 2c, for the platform 2 to be also upturned.
In accordance with the illustrated embodiment, these first and second anchors 4a, 4b are metal pins secured to the platform, having a substantially frustoconical head projecting into surface hollows 24a, 24b.
Metal pins of this type are sold, for example, by HALFEN-DEHA S.r.l. based at Urgnano (BG), Italy.
The modular member 1 also includes a plurality of level adjustment elements 5, 6, to adjust the height and inclination of the platform 2 as it is laid, as explained in greater detail below.
The level adjustment members are operable either from above or from the side that supports the rails 7 or the track equipment 7.
In the illustrated embodiment, each of said level adjustment elements comprises an internally threaded bushing 5, which is inserted in the platform 2, transverse to the main surfaces 2a, 2b, and is designed to receive a screw 6.
The rails and/or the special track equipment parts 7 lie on rubber pads 17 and the rails 7. are connected to the prefabricated modular member 1 by means of an elastic attachment, better known as plate 10.
The rails and/or the special track equipment parts 7 are anchored to said platform 2 by means of screws 30, whose heads are inserted in guides 11, which are embedded in the platform 2 and placed transverse to the rails 7.
In the modular elements designed for straight sections, the guides 11 are usually essentially orthogonal to the rails 7.
In the modular elements designed for switches, the guides 11 are transverse but generally non orthogonal to the rails 7.
Thanks to this arrangement, the transverse - but not necessarily orthogonal - position of rails may be adjusted with the utmost accuracy, while preventing any misalignment between the tracks of adjacent modular members.
This advantage is particularly appreciated when existing tracks are to be joined to new tracks.
In an alternative embodiment (see Figure 10), an additional plate 27 (usually made of iron), is placed between the platform and the rubber pads 17, and is anchored to the platform 2 by means of screws 30, whose heads are inserted in guides 11, which are embedded in the platform 2 and placed transverse to the rails 7.
This arrangement generates an additional thickness for accommodating the stone block pavement.
In the illustrated embodiment, the screws 30 are Halfen HS 50/30 screws and the guides are Halfen HTA 50/30 screws, sold by HALFEN GmbH & Co.KG, Germany.
Further information about these guides may be found in www.halfen-deha.com, reference being expressly made thereto.
The prefabricated modular member may include a housing 14 to receive a switch machine, whenever the platform is designed to be placed in the switch point area.
In the preferred embodiment, one of the main surfaces 2a - particularly the one opposite the surface whereto the tracks are secured - and the lateral peripheral surface 2c are covered by an elastomeric vibration damping mat 9.
This mat is preferably 10 to 30 mm thick.
The prefabricated modular member described herein is used to make a permanent way, including tracks and track equipment.
The process for making the permanent way including tracks and track equipment 7 using the above prefabricated modular members includes a first excavation step to form a trench 12 and later compaction of the bottom 13 of the trench 12.
A poor concrete cast having a thickness of 10 to 20 cm is possibly applied to the bottom 13 of the trench 12.
One or more steel plates 20 are further placed on the bottom of the trench.
Now, at least one prefabricated modular member 1 is placed in the trench 12.
Using the level adjustment elements - e.g. the screws 6 in the bushings 5 - the height and inclination of each prefabricated modular member 1 are adjusted.
Then a special self-leveling bearing mortar is injected in the trench 12 until the whole space under the platform 2 and a portion of the space between the lateral surface 2c of the platform and the sidewalls of the trench are filled.
This special self-leveling mortar may be the "MICROBETON BS91 ANCORA", sold by TECNOCHEM ITALIANA S.r.l., based at Barzana (BG), Italy.
As mortar is injected, the vent-holes 3 allow all the air trapped under the platform 2 to be exhausted, to obtain full mortar filling.
Once the special self-leveling mortar has set, the adjustment screws 6 are removed.
If requested, the transverse position of the rails 7 of each modular member 1 may be also adjusted, to prevent any misalignment between adjacent track sections.
Those skilled in the art will appreciate the various advantages of this method, and particularly the very short times needed for laying the tracks and the track equipment (about three days).

Claims

A prefabricated modular member (1) for making a permanent way, including tracks and track equipment, comprising:
- a reinforced concrete platform (2) having two main surfaces (2a, 2b) and one lateral peripheral surface (2c);

- at least one vent-hole (3) whose ends open out of said two main surfaces (2a, 2b);

- a plurality of level adjustment elements (5, 6) to adjust the height and inclination of said platform (2);

- at least one pair of rails or special track equipment parts (7) secured to one of the main surfaces (2b) of said platform (2),
characterized in that it includes a plurality of first anchors (4a) at one of said main surfaces (2a, 2b), to allow lifting and handling of said platform (2);
and in that said rails or special track equipment parts (7) are anchored to said platform (2) by means of screws (30), which are held in guides (11) embedded in said platform (2), said guides (11) being oriented transverse to said rails (7).
A prefabricated modular member as claimed in claim 1, further comprising a plurality of second anchors (4b) located at said lateral peripheral surface (2c), to allow upturning of said platform (2).
A prefabricated modular member (1) as claimed in claim 1 or 2, wherein each of said level adjustment elements comprises an internally threaded bushing (5), which is inserted in said platform (2), transverse to said main surfaces (2a, 2b), and a screw (6) receivable in said bushing (5).
A prefabricated modular member (1) as claimed in claim 1 or 2 or 3, characterized in that said rails or the special track equipment parts (7) lie on rubber pads (17) and said rails (7) are connected to the prefabricated modular member (1) by means of an elastic attachment (10).
A prefabricated modular member (1) as claimed in claim 1 or 2 or 3 or 4, characterized in that said screws (10) are Halfen HS 50/30 screws, and said guides (11) are Halfen HTA 50/30 guides.
A prefabricated modular member (1) as claimed in any of the preceding claims, characterized in that it comprises a housing (14) to receive a switch machine, if the platform is specially designed for switch points.
A prefabricated modular member as claimed in any of the preceding claims, wherein the thickness of said platform (2) is of 150 to 300 mm.
A prefabricated modular member as claimed in any of the preceding claims, wherein said at least one vent-hole (3) has a diameter of 40 to 60 mm.
A prefabricated modular member (1) as claimed in any of the preceding claims, wherein one of said main surfaces (2a, 2b) is covered with an elastomeric vibration damping mat (9).
A prefabricated modular member (1) as claimed in the preceding claim, wherein said mat (9) has a thickness of 10 to 30 mm.
A prefabricated modular member (1) as claimed in any of the preceding claims, wherein said main surfaces (2a, 2b) are substantially parallel.
A permanent way, including tracks and track equipment, characterized in that it includes at least one prefabricated modular member as claimed in any of claims 1 to 11.
A process for making a permanent way, including tracks and track equipment (7), comprising the steps of:
- excavating a trench (12);

- compacting the bottom (13) of said trench (12);

- placing one or more steel plates (20) on the bottom of said trench (12);

- placing at least one prefabricated modular member (1) as claimed in any of claims 1 to 12, in said trench (12);

- adjusting the height and inclination of said prefabricated modular member (1) using said level adjustment elements (5);

- injecting a special self-leveling load bearing mortar in said trench (12) until the whole space under the platform (2) and a portion of the space between the lateral surface (2c) of the platform and the sidewalls of said trench (12) are filled.
A process for making a permanent way including tracks and track equipment (7) as claimed in claim 13, wherein a poor concrete cast, having a thickness of 10 to 20 cm, is applied to the bottom (13) of said trench (12) before placing one or more steel plates (20) on the bottom of the trench (12).
A process for making a permanent way including tracks (7) and track equipment (7) as claimed in claim 13 or 14, including the additional step of removing said level adjustment elements (6).
A process for making a permanent way including tracks and track equipment (7) as claimed in claim 13, 14 or 15, including the additional step of adjusting the transverse position of rails (7).