[0001] This invention relates to a method and an apparatus for removing ballast from a road
bed and, more particularly, to an improved method and apparatus for removing ballast
from a rail road bed, which apparatus can be controlled by a sole operator using a
single vehicle to lift and remove ballast.
[0002] When preparing an area of ground for the laying of a road or railroad, the designated
area is excavated and ballast material is laid along the route. The ballast material
generally takes the form of gravel or broken stone and, in the case of a railroad,
is placed on the excavated bed to provide a firm surface upon which the track is supported.
The ballast also functions to hold the track in position when laid. Furthermore, the
ballast material facilitates drainage of surface water from the rail bed to avoid
flooding in bad weather.
[0003] Under some conditions, the ballast may become dislodged from the rail bed or, in
some cases where safety checks or rail maintenance operations must be carried out,
the ballast may require removal either for replacement or cleaning operations to be
carried out. This is particularly important if the ballast becomes clogged with dirt
and debris as the proper drainage function will be impaired which could lead to flooding
in low lying areas thereby requiring further safety operations to be carried out on
the same stretch of track.
[0004] Traditional methods of removing ballast require the removal of the rails, which are
stored at a location perhaps adjacent to the railway line. A fleet of vehicles is
then transported to the site to handle the removal operation. It is not unusual for
at least 4 separate vehicles to be required, with personnel required for each vehicle.
[0005] Ballast is dug up from the rail bed for example using suitable earth moving equipment
and the recovered ballast is then loaded into wagons to be removed from the site.
Often the area in which the operation is taking place is difficult to access from
road networks and this can add further time delays caused by the removal operation
itself.
[0006] These traditional methods are both labour intensive in requiring different personnel
to operate the various pieces of equipment and also time consuming in requiring equipment
to be brought to the site and removed therefrom as required. For example, the earth
moving equipment may have to be moved to and from the work site several times in order
to fill a wagon with sufficient ballast. Furthermore, the earth moving equipment may
have to be removed from the work site to allow the wagon access to the work site for
loading. This leads to a situation where either the work is progressed in stages to
allow for the required equipment to be on hand at the appropriate times, or alternatively
in a labour intensive operation which relies on a fleet of vehicles and a work force
to operate the vehicles as and when required.
[0007] The present invention aims to provide a method and apparatus for removing ballast
from a road way and particularly from a railway line, which overcomes or at least
mitigates some of the above mentioned disadvantages which are associated with traditional
methods and apparatus used for removing ballast from such locations.
[0008] US 5 228 552 discloses a mineral mining apparatus which can be moved into a mining position by
tracks 1. Then a stabilising foot is dropped at the rear of the device prior to a
cutter drum scavaging mining material with mined material then being carried onto
the loading platform and swept onto a conveyor by rotatably mounted loading star-wheels.
Then the mining is ceased before the apparatus is advanced again and the operation
repeated.
[0009] FR 2 588 023 and
FR 1 387 729 disclose the swinging down of an excavator-elevator about a pivoting axis. In
FR 2 588 028 after the excavator has made contact with the ballast 9 at the head of a stretch,
the excavator removes the ballast to the depth of the formation bed. A shovel 10 is
then activated to pick up ballast and push it towards the excavator. Once a section
has been removed the whole apparatus is then advanced again and the operation is repeated.
[0010] According to one aspect of the present invention there is provided a method of continuous
removal of ballast material from a bed comprising the steps of:
positioning ballast removal apparatus (1) at a work site;
advancing (2) the apparatus along the bed to excavate and lift ballast from the bed
with a loading apron (6) thereby introducing the lifted ballast into the apparatus
at one end thereof; and
conveying (10) the lifted ballast from the point of lifting, through the apparatus,
to a selectively positionable delivery means (11) at the other end of the apparatus
remote from the excavation site, from which the ballast is fed to a containment means
for collection.
[0011] According to a further aspect of the present invention, ballast removal apparatus
for the continuous removal of ballast, from a bed, said apparatus comprising:
excavating and lifting means comprising a loading apron (6) and control means for
advancing the loading apron, the control means, when activated being arranged, in
use, to cause the loading apron (6) to excavate and lift ballast from the bed;
conveying means (10) for moving the ballast from the lifting means through the apparatus,
and
selectively positionable delivery means (11) for delivering ballast from the conveying
means to a point of collection.
[0012] Advantageously, the above apparatus can be controlled by a sole operator. As the
operation of the apparatus is continuous, the operator does not need to carry out
the removal operation in stages but can drive the apparatus the length of the rail
bed within which the ballast is to be removed and excavate and collect the ballast
in a single operation.
Figure 1 is a schematic side view of an apparatus for removing ballast from a road way in
accordance with one aspect of the present invention;
Figure 2 is a schematic front view of the apparatus of Figure 1 in operation adjacent a wagon
for collecting ballast; and
Figure 3 is a schematic overhead view of the apparatus of Figure 1 in operation.
[0013] Turning now to the Figures there is shown in Figures 1-3 an apparatus for removing
ballast from a road way, particularly from a rail road bed. The apparatus is incorporated
into a vehicle
1 which is intended to be driven and controlled by a single operator thereby overcoming
the labour intensive problems associated with the prior art methods and apparatus
used.
[0014] As shown in Figure 1, an apparatus for removing ballast comprises a vehicle
1 provided with suitable transport means
2. In the illustrated embodiment, the vehicle comprises a main frame
3 to which the transport means
2 for advancing the vehicle along a road bed are connected in a conventional manner.
Advantageously, transport means
2 includes caterpillar tracks
4 mounted on either side of the vehicle and this provides adhesion to the ground for
the apparatus to penetrate the ballast and these also allow the vehicle to be driven
directly over rough or uneven ground in order to gain access to the road way to be
worked on.
[0015] The apparatus further comprises means for excavating and lifting ballast from the
rail bed. The excavation means
5 is mounted on the front of the main frame
3 of the vehicle (as determined by the direction of operation of the vehicle) and comprises
a loading apron
6 which may be formed of a wear resistant material. The loading apron comprises a generally
C-shaped member which is mounted to the main frame at the closed end thereof.
[0016] Means (not shown) are provided on the mainframe
3 for raising and lowering the loading apron
6 towards and away from the rail bed and also for altering the transverse relationship
with the main frame. This allows the position of the loading apron to be adjusted
in order to ensure that the loading apron maintains the optimum position during operation.
[0017] Feeding means are provided within the loading apron
6 to encourage ballast excavated and lifted by the loading apron to pass through it
back towards the main frame
3 of the vehicle. The feedings means in the illustrated embodiment comprise a pair
of rotors
8 which are mounted side by side within the loading apron and a set of spill plates
7. The rotors are each provided with a plurality of blades
9 which may be formed of a wear resistant material. The blades are of a sufficient
length as to advance ballast towards the centre of the loading apron. Means are provided
within the loading apron of the vehicle for rotating the rotors
8 in opposite directions to facilitate advancement of the ballast.
[0018] Conveyor means are provided within the main frame
3 of the vehicle for conveying ballast from the loading apron
6 to the rear of the vehicle. The conveyor means may be in the form of a conveyor belt
10. In the illustrated embodiment, the height of the conveyor belt increases as it passes
through the vehicle
1. Means (not shown) may be provided on the main frame to adjust the height of the conveyor
belt
10 if required. It is envisaged that the conveyor belt will be driven by hydraulic means
provided on the main frame. Additionally, tensioning means may be provided in order
to adjust the tensioning of the conveyor belt to achieve optimum operation of the
apparatus.
[0019] At the other end of the conveyor belt
10, remote from the loading apron
6, a selectively positionable feeding means is mounted to the rear of the vehicle. The
feeding means takes the form of a boom member
11 mounted onto the main frame
3 by suitable fixings which allow the position of the boom
11 to be adjusted as required.
[0020] The boom member is provided with a further conveyor belt
12 which extends along the entire length of the boom. As with the primary conveyor belt
10, this secondary conveyor belt may be provided with tensioning means to adjust the
operational characteristics of the belt.
[0021] A control cab
13 is mounted on the main frame
3 of the vehicle and in the illustrated embodiment is shown as being located behind
the loading apron
6 and above the primary conveyor belt
10. It is envisaged that the cab will be fully glazed in order to provide maximum visibility
for the operator during use. Furthermore, the position of the cab allows the operator
to oversee the operation of the apparatus in order that he can make any adjustments
necessary during the excavation process.
[0022] Control means (not shown) are provided within the cab, as will be described further
below, for operating the vehicle. Such control means may, for example, comprise amongst
other things, means for operating and controlling the speed of the primary and secondary
conveyor belts
10,12, control means for raising and lowering the loading apron
6, control means for advancing, retracting and tilting the loading apron and control
means for adjusting the position of the boom
11. Additionally, standard vehicle control means will also be provided within the cab
which will allow the vehicle to be driven along standard roads to any particular location
where it may be required.
[0023] A wagon
14 is illustrated in the figures for collecting ballast excavated from the rail bed
by the apparatus described above. The wagon is shown as being provided on an adjacent
rail to the rail bed being cleared, although the wagon could of course be replaced
with a skip or truck which can be moved along the rail bed together with the excavation
apparatus in order to facilitate continuous operation of the apparatus.
[0024] This enables the apparatus to remove ballast in a single pass along the rail bed
rather than a series of backwards and forwards operations to remove ballast and then
return to a collection device to load recovered ballast onto a suitable means to allow
for removal from the work site.
[0025] Additional control means (not shown) for the various components of the apparatus
may also be mounted on the mainframe
3 of the vehicle. This may include for example, power packs, fuel tank, electric and
hydraulic equipment, service jacks and other associated means.
[0026] The operation of the apparatus will now be described with reference to the Figures.
Firstly, the rails of the railroad bed from which the ballast is to be excavate are
removed and stored at a suitable location such as adjacent to the rail bed. The removal
apparatus as described above is then moved into position on the rail bed. The vehicle
1 upon which the apparatus is located may be driven to the required location or may
alternatively be transported to the required location via the existing rail network
prior to removal of the rails.
[0027] Wagons
14 or other suitable collection means is then provided adjacent to the collection apparatus
and it is intended that the collection apparatus should be advanced together with
the apparatus. It is therefore preferable that a wagon or wagon train be positioned
on adjacent tracks to the rail bed to be removed to allow the apparatus to deposit
collected ballast into the successive wagons.
[0028] Prior to use of the apparatus, the position of the boom
11 is adjusted so that the free end of the boom and the conveyor belt
12 provided thereon is located above the wagon
14 or truck into which the excavated ballast is to be loaded.
[0029] As shown in Figures 2 and 3, the position of the loading apron
6 of the apparatus can be adjusted, grading down into the ballast in order to bring
the front of the loading apron into engagement beneath ballast to be removed. The
loading apron 6 and primary and secondary conveyor belts
10,12 are activated by the operator of the apparatus. As the vehicle
1 is advanced forwards along the rail bed, ballast is lifted into the loading apron.
[0030] Contra rotation of the two rotors
8 directs excavated ballast between the blades
9 and moves the ballast through the loading apron
6 onto the end of the primary conveyor belt
10 which is located within the loading apron.
[0031] The excavated ballast is then carried along the primary conveyor belt until it reaches
the end of the belt at the rear of the main frame
3. It then falls from the end of the primary conveyor belt and drops onto the secondary
conveyor belt
12 provided on the boom member
11 at the rear of the main frame. The ballast is carried along the secondary conveyor
belt and falls from the free end of the conveyor belt into the wagon
14 or other collection means provided adjacent to the rail bed.
[0032] As the position of the boom member
11 and therefore the end of the secondary conveyor belt
12 can be controlled by the operator from within the cab, any inconsistencies in the
distance between the vehicle and the adjacent collection means can be compensated
for by suitable movement of the boom member.
[0033] Indicator means (not shown) may be provided within the cab
13 of the vehicle to allow the operator to monitor the position of the boom and to allow
him to make suitable adjustments without interrupting the operation of the apparatus.
This enables the apparatus to be operated more efficiently and facilitates the one-pass
operation of the apparatus as previously described.
[0034] In the embodiment shown in Figure 2, a wagon train is provided adjacent to the rail
bed from which ballast is to be removed. In this embodiment, the apparatus can be
driven along the rail bed excavating ballast as it advances. The ballast falling from
the secondary conveyor belt fills each successive wagon as the apparatus advances
along the bed. Once all of the wagons are filled they can be simply transported along
the rail track to a suitable location for unloading.
[0035] It is to be understood that although the above description has been particularly
directed towards the excavation of ballast from a rail way bed, the apparatus and
method described could equally be used for the excavation of ballast from a road bed.
[0036] As has been described above, the method and apparatus allows for the continuous excavation
of ballast from a road or railroad bed by a sole operator in a single vehicle with
a single pass along the bed by the vehicle. This provides a significant advantage
over prior art excavation methods and apparatus used therein.
1. A method of continuous removal of ballast material from a bed comprising the steps
of:
(i) positioning ballast removal apparatus (1) at a work site;
(ii) advancing (2) the apparatus along the bed to excavate and lift ballast from the
bed with a loading apron (6) thereby introducing the lifted ballast into the apparatus
at one end thereof; and
(iii) conveying (10) the lifted ballast from the point of lifting, through the apparatus,
to a selectively positionable delivery means (11) at the other end of the apparatus
remote from the excavation site, from which the ballast is fed to a containment means
for collection.
2. The method is claimed in claim 1
characterised in that it further comprises:
bringing a front portion of the loading apron (6) of said ballast removal apparatus
into engagement beneath ballast to be removed.
3. The method as claimed in claim 2 characterised in that said loading apron (6) is a generally C-shaped member having an upwardly inclined
inner lifting surface.
4. The method as claimed in claim 2
characterised in that it further comprises:
adjusting the vertical position of the front portion of the loading apron (6) as the
ballast removal apparatus advances grading down into the ballast in order to locate
the front of the apron beneath ballast on the bed.
5. The method as claimed in claim
characterised in that it further comprises:
prior to said step of lifting ballast, removing rails from a railway line previously
laid on the ballast in a region of the railway line from which ballast is to be removed.
6. Ballast removal apparatus for the continuous removal of ballast from a bed, said apparatus
comprising:
(a) excavating and lifting means;
(b) conveying means (10) for moving the ballast from the lifting means through the
apparatus, and
(c) selectively positionable delivery means (11) for delivering ballast from the conveying
means to a point of collection characterised in that the excavating and lifting means comprises a loading apron (6) and control means
for advancing the loading apron, wherein the control means, when activated in use,
causes the loading apron (6) to continuously excavate and lift ballast from the bed.
7. An apparatus according to claim 6, characterised in that the lifting means comprises feeding means (8) for feeding the lifted ballast onto
the conveying means.
8. An apparatus as claimed in claim 6, characterised in that said loading apron (6) is mounted for independent vertical and/or transverse movement
with respect to said main body.
9. An apparatus as claimed in claim 6 characterised in that said loading apron (6) is substantially C-shaped.
10. An apparatus according to claim 6, characterised in that the selectively positionable delivery means comprises a boom (11) mounted on the
rear of the apparatus.
11. An apparatus according to claim 10, characterised in that the boom (11) is provided with conveyor means (12) for moving the ballast along the
length of the boom.
12. An apparatus according to claim 11, characterised in that the conveying means passing through the apparatus comprises a conveyor belt (10)
from which ballast can fall onto the conveyor means (12) of the boom (11).
13. An apparatus according to claim 7, characterised in that the feeding means comprises a pair of contra rotating rotors (8) provided with blades
which direct the lifted ballast therebetween and deposit it onto the conveyor means.
14. An apparatus according to any one of claims 6 to 13, characterised in that the apparatus is provided with means for transporting the apparatus to and from the
rail bed.
15. An apparatus according to claim 14, characterised in that the apparatus may be provided with caterpillar tracks (4) to allow the apparatus
to be driven over rough or uneven ground as well as normal road surfaces.
1. Verfahren zum kontinuierlichen Entfernen von Ballastmaterial von einem Bett, umfassend
die Schritte:
(i) Positionieren der Ballastentfernungsvorrichtung (1) an einer Arbeitsstelle;
(ii) Vorrücken (2) der Vorrichtung entlang des auszuhebenden Bettes und Heben des
Ballasts vom Bett mit einer Ladeschaufel (6), wobei der gehobene Ballast in die Vorrichtung
an einem ihrer Enden geführt wird; und
(iii) Fördern (10) des angehobenen Ballasts von der Stelle des Aushubs durch die Vorrichtung
zu einem selektiv positionierbaren Übergabemittel (11) am anderen Ende der Vorrichtung,
welches entfernt von der Stelle des Aushubs liegt, von welchem der Ballast zur Sammlung
einem Aufnahmemittel zugeführt wird.
2. Verfahren nach Anspruch 1,
dadurch gekennzeichnet, dass es weiters umfasst:
Eingreifen eines vorderen Abschnitts der Ladeschaufel (6) der genannten Ballastentfernungsvorrichtung
unter dem zu entfernenden Ballast.
3. Verfahren nach Anspruch 2, dadurch gekennzeichnet, dass die genannte Ladeschaufel (6) ein im Wesentlichen C-förmiges Bauteil mit einer nach
oben ansteigenden inneren Hebefläche ist.
4. Verfahren nach Anspruch 2,
dadurch gekennzeichnet, dass es weiters umfasst:
Einstellen der vertikalen Position des vorderen Abschnitts der Ladeschaufel (6), wenn
die Ballastentfernungsvorrichtung vorrückt und nach unten in den Ballast eindringt,
um die Front der Schaufel unter dem Ballast auf dem Bett zu positionieren.
5. Verfahren nach Anspruch 1,
dadurch gekennzeichnet, dass es weiters umfasst:
vor dem genannten Schritt des Hebens des Ballasts, Entfernen der Schienen von einer
Schienenstrecke, welche zuvor auf den Ballast verlegt wurden, in einem Bereich der
Schienenstrecke, aus welchem der Ballast entfernt werden soll.
6. Ballastentfernungsvorrichtung für das kontinuierliche Entfernen von Ballast von einem
Bett, wobei die Vorrichtung umfasst:
(a) Aushub- und Hebemittel;
(b) Fördermittel (10), um den Ballast vom Hebemittel durch die Vorrichtung zu bewegen;
(c) selektiv positionierbare Übergabemittel (11), um den Ballast vom Fördermittel
zu einem Sammelpunkt zu bringen, dadurch gekennzeichnet, dass das Aushub- und Hebemittel eine Ladeschaufel (6) und eine Kontrolleinrichtung umfasst,
um die Ladeschaufel voranzutreiben, wobei die Kontrolleinrichtung, wenn sie im Betrieb
aktiviert ist, die Ladeschaufel (6) dazu veranlasst, kontinuierlich Ballast auszuheben
und vom Bett zu heben.
7. Vorrichtung nach Anspruch 6, dadurch gekennzeichnet, dass die Hebeeinrichtung Zuführmittel umfasst, um den gehobenen Ballast dem Fördermittel
zuzuführen.
8. Vorrichtung nach Anspruch 6, dadurch gekennzeichnet, dass die genannte Ladeschaufel (6) für unabhängige vertikale und/oder transversale Bewegung
in Bezug auf den genannten Hauptkörper geeignet montiert ist.
9. Vorrichtung nach Anspruch 6, dadurch gekennzeichnet, dass die genannte Ladeschaufel (6) im Wesentlichen C-förmig ist.
10. Vorrichtung nach Anspruch 6, dadurch gekennzeichnet, dass das selektiv positionierbare Übergabemittel einen Ausleger (11) umfasst, welcher
am Heck der Vorrichtung montiert ist.
11. Vorrichtung nach Anspruch 10, dadurch gekennzeichnet, dass der Ausleger (11) mit einem Fördermittel (12) versehen ist, um den Ballast entlang
der Länge des Auslegers zu bewegen.
12. Vorrichtung nach Anspruch 11, dadurch gekennzeichnet, dass das Fördermittel, welches durch die Vorrichtung läuft, einen Förderband (10) umfasst,
von welchem der Ballast auf das Fördermittel (12) des Auslegers (11) fallen kann.
13. Vorrichtung nach Anspruch 7, dadurch gekennzeichnet, dass das Zuführmittel ein Paar von sich gegenseitig drehenden Rotoren (8) aufweist, welche
mit Blättern versehen sind, welche den angehobenen Ballast zwischen sich führen und
auf dem Fördergürtel deponieren.
14. Vorrichtung nach einem der Ansprüche 6 bis 13, dadurch gekennzeichnet, dass die Vorrichtung mit Mitteln zum Transportieren der Vorrichtung zu und von dem Schienenbett
ausgestattet ist.
15. Vorrichtung nach Anspruch 14, dadurch gekennzeichnet, dass die Vorrichtung mit einem Raupenantrieb (4) ausgestattet ist, um der Vorrichtung
zu ermöglichen, sowohl über rauen oder unebenen Grund als auch über normale Straßenoberflächen
gefahren zu werden.
1. Procédé de retrait continu d'un matériau de ballast d'une infrastructure (ou assiette)
de voie, comprenant les étapes consistant à :
(i) positionner un dispositif de déballastage (1) sur un chantier ;
(ii) faire avancer (2) le dispositif le long de l'infrastructure pour excaver et soulever
le ballast de l'infrastructure avec un tablier de chargement (6), introduisant ainsi
le ballast soulevé dans le dispositif à une extrémité de celui-ci ; et
(iii) transporter (10) le ballast soulevé depuis le point de soulèvement, à travers
le dispositif, jusqu'à un moyen de décharge positionnable sélectivement (11) à l'autre
extrémité du dispositif, distante du site d'excavation, depuis lequel le ballast est
introduit dans un moyen de rétention en vue de sa collecte.
2. Procédé selon la revendication 1,
caractérisé en ce qu'il comprend de plus :
le fait d'amener une partie antérieure du tablier de chargement (6) dudit dispositif
de déballastage en engagement sous le ballast à retirer.
3. Procédé selon la revendication 2, caractérisé en ce que ledit tablier de chargement (6) est un élément globalement de forme générale en C
ayant une surface de levage intérieure inclinée vers le haut.
4. Procédé selon la revendication 2,
caractérisé en ce qu'il comprend de plus :
l'ajustement de la position verticale de la partie antérieure du tablier de chargement
(6) à mesure que le dispositif de déballastage avance en s'enfonçant dans le ballast
pour placer l'avant du tablier sous le ballast situé sur l'infrastructure.
5. Procédé selon la revendication 1,
caractérisé en ce qu'il comprend de plus :
avant ladite étape de soulèvement du ballast, le retrait des rails d'une ligne de
chemin de fer précédemment posée sur le ballast dans une portion de la ligne de chemin
de fer de laquelle le ballast doit être retiré.
6. Dispositif de déballastage pour le retrait continu de ballast d'une infrastructure
(ou assiette) de voie, ledit dispositif comprenant :
(a) des moyens d'excavation et de soulèvement ;
(b) des moyens de transport (10) pour déplacer le ballast depuis les moyens de soulèvement,
à travers le dispositif ; et
(c) des moyens de décharge (11) positionnables sélectivement pour décharger le ballast
depuis les moyens de transport jusqu'à un point de collecte, caractérisé en ce que les moyens d'excavation et de soulèvement comprennent un tablier de chargement (6)
et des moyens de contrôle pour faire avancer le tablier de chargement, dans lequel
les moyens de contrôle, quand ils sont activés en service, forcent le tablier de chargement
(6) à excaver et soulever de manière continue le ballast de l'infrastructure.
7. Dispositif selon la revendication 6, caractérisé en ce que les moyens de soulèvement comprennent des moyens d'alimentation (8) pour alimenter
le ballast soulevé sur les moyens de transport.
8. Dispositif selon la revendication 6, caractérisé en ce que ledit tablier de chargement (6) est monté pour un mouvement vertical et/ou transversal
indépendant par rapport audit corps principal.
9. Dispositif selon la revendication 6, caractérisé en ce que ledit tablier de chargement (6) a sensiblement la forme d'un C.
10. Dispositif selon la revendication 6, caractérisé en ce que les moyens de décharge positionnables sélectivement comprennent une flèche (11) montée
à l'arrière du dispositif.
11. Dispositif selon la revendication 10, caractérisé en ce que la flèche (11) est munie de moyens transporteurs (12) pour déplacer le ballast sur
la longueur de la flèche.
12. Dispositif selon la revendication 11, caractérisé en ce que les moyens de transport traversant le dispositif comprennent une bande transporteuse
(10) depuis laquelle le ballast peut tomber sur les moyens transporteurs (12) de la
flèche (11).
13. Dispositif selon la revendication 7, caractérisé en ce que les moyens d'alimentation comprennent une paire de rotors (8) tournant en sens inverse,
munis de lames qui dirigent entre elles le ballast soulevé et le déposent sur la bande
transporteuse.
14. Dispositif selon l'une quelconque des revendications 6 à 13, caractérisé en ce que le dispositif est muni de moyens pour transporter le dispositif jusqu'à, et depuis,
l'infrastructure de voie de chemin de fer.
15. Dispositif selon la revendication 14, caractérisé en ce que le dispositif peut être muni de chenilles (4) pour permettre au dispositif d'être
conduit sur un terrain accidenté ou irrégulier aussi bien que sur des chaussées normales.