Railway construction

Abstract

 A rail way flush with a car road or driving lane wherein the two parallel rails (2) are each provided in a trench (3) in the road surface, wherein the rail is embedded in embedding material (6) and wherein the rail is part of a prefab unit (11) comprising the rail and the embedding material in a tray structure. The tray structure is longitudinally divided and the gaps are filled with a flexible filling material with which expansions can be accomodated.

Description

[0001] This invention relates to a railway structure for train, streetcar or subway, etc., particularly within a car road, wherein the rails are flush with the road surface. It is appreciated that "car road" means any road designed for road traffic, among which pedestrians, cyclists, passenger cars, trucks and motor cycles.

[0002] Such infra systems wherein rail and road are combined, are mainly applied in city area's due to the lack of space there. Combining traffic systems is then obvious, a.o. in relation with efficiency but also economy. The invention is however also applicable to other locations, such as industrial terrains, tunnels or non-city area's.

[0003] NL-A-1007815 discloses a rail structure wherein two parallel rails are each located in a separate trench into an attachment layer of a porouss starting material with a relatively large percentage cavities, such as ZOAB (Zeer Open Asfalt Beton; Very Open Asphalt Concrete), wherein said cavities are filled at a later time with a curing stiffening agent, e.g. based on cement. The rails are fixed within the trenches by means of a plastic pouring mass. Thus it is not required for the rail fixation to mutually couple the rails by sleepers, coupling rods or other fixating elements, or to use a concrete foundation to which the rails are fixed. The attachment layer can relatively quickly and simply be applied with the aid of e.g. known asfalt spreading techniques, such that the drive plane is quickly available for the car traffic. Since the road paving provides the foundation, costs are reduced.

[0004] With the system known from NL-A-1007815, the rails have to be provided, set and fixed in situ, which is cumbersome and inaccurate. Also a special top layer structure is required to stabilise the trenches for the rails. This top layer structure can provide no sound reduction.

[0005] DE-U-29611725 discloses a rail structure with mutually coupled rails, flush with a car road, wherein aside the rail a row is provided of concrete edge elements, extending the complete height of the rail. Each edge element is glued to the concrete sub structure by special mortar. The object of this prefabricated edge element is avoiding collapse of the road surface directly adjacent the rail and the instabilities because of that.

[0006] EP-A-0.737.778 discloses a sound demping rail structure wherein the two rails are each located in a seperate trench in a concrete or steel foundation. Between and adjacent the rails a layer of sound absorbing material is provided, such as ZOAB. This rail structure is not located in a car road. Data about the fixation of the rails are not available.

[0007] US-A-5513797 discloses the use of special formed rails for combined infrastructure systems with a cement concrete rouad structure wherein afterwards the trench for the rail is machined. De rail has at both sides projecting flanges at its top which are adapted to bear at the road structure and from which the in the trench in the road surface located rail will be suspended. These flanges provide a relatively large contact surface with the road structure for a proper load distribution. Fig. 4 of this US discloses an embodiment for a relatively weak road structure, for which first a prefabricated cement concrete beam with trenches of approx. 5 m length is located in the cement concrete road structure. Then the rail is located in the beam with trenches. Since the beam and the rail are separately provided subsequently, hughe setting operations are required in situ. The teachings of the known infra system are useless for road structures of substantially weaker materials than cement concrete, such as (asphalt concrete) mixtures, possibly with sound reducing properties, e.g. ZOAB, a.o. due to the heavy loads, draining into the road structure of the cast mortar wherein the rail is embedded, unfavourable coefficients of expansion.

[0008] In Germany in the 1950's a system was developed comprising short prefab cement concrete slabs which were already provided with both rails by the factory. This system appeared unstable.

[0009] The prior art suggests, that for a combined infra system the road structure has to be made in cement concrete or asphalt concrete treated with a curing stiffening agent. For a combined infra system cement concrete has however some improtant shortcomings, such as relatively extended curing time, the requirement for expansion gaps, the cumbersome accessibility of the infra structure below. Thus application of cement concrete results a.o. in extended road blocks, instabilities and bad maintainability of the infrastructure.

[0010] A special problem is that the combined infrasystem mostly needs to be fit in the already existing road which may be blocked as short as possible during rebuilding.

[0011] For a succesful application of such combined infra system one of the following aspects can be important:

• the structure needs to be durable;
• the trench in the road surface, housing the rail, must bear the loads due to passing traffic;
• the loads acting on the rails must be transmitted to the substrate in the correct manner;
• the structure needs to be such that passing traffic generates a minimum of sound and vibration exposure of the surroundings. This can e.g. be offered by sound reducing top layers for the road surface (e.g. ZOAB) and/or embedment of the rails with adapted mortar and damping material, but also by decreasing the sensitivity for inaccuracies, or by using prefab elements;
• the construction work must be such that it can be carried out quick and/or phased with minimum traffic disturbance, to be e.g. met by application of prefab elements and/or elimination of the use of sleepers, coupling rods or other elements mutually fixating the rails;
• maintenance to the structure must be possible, wherein also the substrate or lower infrastructure must be accessible without the requirement to completely remove the structure and rebuild it.

[0012] Starting from the above the object of this invention is an improved rail structure, particularly for application to a car road. Particularly the object of this invention is a rail structure wherein the rails are located, preferably fixated, each in an own trench in a road paving, wherein said road paving preferably at least partly provides the rail foudation. Particularly the road paving and/or the substructure for it is preferably not provided as (reinforced) cement concrete or other ridgid material (possibly poured in situ or built from prefab elements). Most preferably the road paving and/or the substructure for it, or at least a (substantial) part thereof is provided in non-rigid material, e.g. asphalt concrete or a material with processing characteristics (e.g. application speed, curing time to drivability by cars) comparable to those of asphalt concrete.

[0013] According to this invention is proposed, a rail way flush with a car road wherein two parallel rails are each provided in a trench in the road surface, wherein the rail is embedded in embedding material and wherein

• the rail is part of a prefab unit comprising at least the rail and the embedding material; and/or
• a wall element is present between the road surface material and the rail, wherein preferably embedding material is present between said wall element and the rail.

[0014] Most preferred is the embodiment wherein the rail, the embedding material and the wall element belong to said prefab element.

[0015] Preferably the wall element is part of a structure enclosing said rail at at least one of the longitudinal sides and the under side. Thus the rail can be housed in an open tray structure, open at the top.

[0016] Surprisingly experiments have shown that pre fabrication offers important advantages for the structure in curves. In curves the setting also comprises accurate canting of the rails and mutually setting both rails in vertical sense. These operations can be better controled in the factory.

[0017] Preferably the wall or tray structure is longitudinally divided in (tray like) elements. The gap between these elements is preferably filled with a preferably flexible filling material, such as a mortar, with which possible residual expansions can be accomodated. To strengthen the edge of the trench in the road surface and avoid damage thereof, the upper edge of the wall of trench structure is preferably at the same level as the road surface plane.

[0018] If the term "asphalt concrete" is used here, also other paving materials like gravel or stone like granules, bound with bituminous (like) or thermoplastic binders, are meant.

[0019] Thus it is possible with the invention to quickly and efficiently install the rails wherein in a reliable manner a desired and also long service life and low maintenance sensitivity are obtained. Particularly the wall element offers due to its large contact area a proper load transmission between de rail and the car road. The corners of the tray section can be adapted/optimised for a larger stability and/or an improved load transmission.

[0020] The invention also relates to the prefab element as such, e.g. adapted for application in the railway structure according to this invention.

[0021] Further objects, advantages, measurements, embodiments etc. of the invention will follow from the further description of a presently prefered embodiment, refering to the enclosed drawing.

[0022] Fig. 1 shows the section of a partly illustrated drive lane with flush railway;

[0023] Fig. 2 shows a cross section of the prefab arrangement of this invention.

[0024] The car road 1 is build is disclosed in NL-A-1007815 (incorporated by reference), and corresponding reference signs are applied to indicate corresponding parts, while also reference is made to the section of NL-A-1007815, from page 3, line 8 to the end for a discussion of said parts. It will be appreciated that the layer of cement concrete is now absent.

[0025] The prefab assembly 10 of fig. 2 contains the rail 2, the embedment agent 6 and the tray structure 11. The embedment agent 6 can be a plastic pouring mass, possibly containing vibration damping filler means. The tray 11 is made of (reinforced) cement concrete, is relatively thick walled and provides two side wall and a bottom element. However it can also be made of another material, e.g. steel plate, polymer concrete, plastic. Also another shape of the tray 11 is feasible. Besides the tray can be thin walled. One of the objects of the tray 11 is to sufficiently protect against damaging the relatively weak material of the edges of the trench 3. For that the upper edge of the tray 11 is preferably substantially at the same level as the driving plane 5.

[0026] This assembly 10 can as a whole be installed in a trench 3 made in an exsisting car road. When a new car road is build, it is possible to first install the assembly 10 at e.g. the foundation layer 8 and subsequently build the driving plane 5, such that the assembly 10 is automatically embedded in the road material, such as the attachment layer 4 and/or the paving layer 7.

[0027] Another example is the situation where first the foundation of the road is applied, possibly including the first lower layers of the paving from e.g. asphalt concrete. On top of that the assemblies 10 are located and glued, possibly into a shallow trench. Thereafter the rest of the paving is applied over the height of the part of the assembly 10 projecting above the trench.

[0028] The assembly 10 is fixed in the trench with a binder that fills the space between the tray 11 and the trench 3.

[0029] It is feasible that within the assembly 10 the rail 2 and the tray 11 are substantially continuous. However it is prefered, a.o. from the view of thermal expansion, to divide the tray 11 lengthwise in an plurality of separate elements along the length of the rail 2, while the rail 2 preferably has an undivided length. E.g. the rail 2 has a length in the order of 15 m, while the elements of the tray 11 have a length in the order of not more than 2 m, preferably shorter than 1 m, such as about 10-20 cm.

[0030] It will be appreciated that also variants belong to the invention, e.g. based on one or more separate aspects of a here disclosed embodiment, possibly in combination with one or more separate aspects of one or more other here disclosed embodiments.

[0031] E.g. it is feasible to use the assembly 10 in a car road wherein indeed there are one or more cement concrete layers. The combination of ZOAB or another porous, preferably bituminous starting material with relatively high percentage (open) cavities and curing stiffening agent for the attachment layer 4 can e.g. be replaced by a layer of carbon binder. The dured stiffening agent could be eliminated from the layer 4 or could be replaced by a curing stiffening agent that is not based upon cement. The ZOAB in the layer 4 could be replaced by another asphalt material with equivalent applicability, e.g. without or with only a relatively small percentage cavities. The paving layer 7 and/or foundation layer 8 can be absent or made of other material. E.g. the rail 2 can bear onto the bottom of the tray 11 through a damping pad or such damping means. The tray 11 could be without bottom, such that the bottom of the prefab assembly is provided by the embedding agent 6.

[0032] It will be appreciated that the embedding material 6 tightly conforms to the rail 2 and/or tray 11.

Claims

1. A rail way flush with a car road or driving lane wherein the two parallel rails are each provided in a trench in the road surface, wherein the rail is embedded in embedding material and wherein

- the rail is part of a prefab unit comprising at least the rail and the embedding material; and/or

- a wall element is present between the road surface material and the rail, wherein preferably embedding material is present between said wall element and the rail.

2. Structure according to claim 1, wherein the rail, the embedding material and the wall element belong to said prefab element.

3. Structure according to claim 1 or 2, wherein the wall element is part of a structure enclosing said rail at at least one of the longitudinal sides and the under side, e.g. such that the rail is accomodated in an open tray structure, open at the top.

4. Structure according to claim 1, 2 or 3, wherein the wall or tray structure is longitudinally divided in (tray like) elements, while the gap between these elements is preferably filled with a preferably flexible filling material, such as a mortar, with which possible expansions can be accomodated.

5. Structure according to any of claims 1-4, wherein the upper edge of the wall of trench structure is at the same level as the road surface plane.

6. Structure according to any of the preceeding claims, wherein the driving lane contains bituminous (like) or thermoplastic binder bound paving material.

7. Prefarbricated assembly, for application in the structure according to any of claims 1-6.

Drawing