GB2268913A

GB2268913A - Intermodal transport

Info

Publication number: GB2268913A
Application number: GB9213961A
Authority: GB
Inventors: Colin Hugh Pearson Ashby; Ronald George Meager
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-07-01
Filing date: 1992-07-01
Publication date: 1994-01-26
Anticipated expiration: 2012-07-01
Also published as: GB2268913B; GB9213961D0

Abstract

The invention provides a road vehicle (T) suitable for carrying on a railway wagon of the low-loader type; the road vehicle comprising a load-carrying body (1) mounted on one or more sets of wheels (3), the vehicle being provided with means for lowering the body from a raised position relative to the wheels (3), in which raised position the vehicle would normally be driven on a road, to a rest position, in which rest position the vehicle would normally be carried in transit on said railway wagon, wherein the raised position and the rest position are a least 40cm apart. <IMAGE>

Description

Improvements in or Relating to Intermodal Transport This invention relates to intermodal transport, and in particular to road trailers adapted for carrying on railway wagons.

The economics of transport dictate that, in general, it is more efficient and economical to carry goods over short distances by road, whilst the carriage of goods by rail becomes more economical over longer distances. One problem with rail transport is that goods will usually need to be transported to the nearest railhead by road, unloaded from the road vehicle and then loaded onto a railway wagon; a process which in the past has tended to be very timeconsuming and labour-intensive. The problem is alleviated to a certain extent by the use of freight containers, but the use of containers is not always convenient or appropriate, and there remains a need for a system of transporting goods which minimises the time and effort involved in transferring goods between road and rail.One solution to this problem is for the road vehicle or trailer containing the goods to be loaded on to the railway wagon. If this could be achieved efficiently, then the savings made in terms of driver costs and fuel costs would be substantial over longer journeys.

However, any designer/manufacturer of a road vehicle intended for use on a railway wagon must take into consideration two conflicting design criteria.

Firstly, the maximum permissable trailer height in mainland Europe is 4.0 metres, and in order to maximise the volume of goods that can be carried by the trailer, it is clearly highly desirable to build the trailer t6 the maximum possible height. Secondly, the maximum loading height for railway wagons used on the UK railway network is 3.8 metres.

A consequence of this relatively low maximum loading height is that hitherto, it has not proved possible to carry full sized road trailers on railway wagons in the UK; because the combined heights of the road trailer and the railway wagons in use would exceed the railway loading gauge.

Intermodal transport systems are currently in use on the British railway system but in order to overcome the problem of the low loading gauge, the heights of the trailer bodies, -and hence their volume, have had to be substantially reduced.

It will readily be appreciated that reducing the trailer volume means that the trailer becomes less economical to operate, and any advantages that might arise through the carriage of the trailer by rail are thereby reduced or cancelled out.

It is an object of the present invention to overcome the aforementioned problems and to provide a full-sized road trailer which can be carried by rail.

In a first aspect the invention provides a road vehicle suitable for carrying on a railway wagon of the low-loader type; the road vehicle comprising a load-carrying body mounted on one or more sets of wheels, the vehicle being provided with means for lowering the body from a raised position relative to the wheels, in which raised position the vehicle would normally be driven on a road, to a rest position, in which rest position the vehicle would normally be carried in transit on said railway wagon, wherein the raised position and the rest position are at least 40cm apart.

In a further aspect, the invention provides a road vehicle chassis mounted on one or more sets of wheels, the road vehicle chassis being provided with means for lowering the chassis from a raised position relative to the wheels, in which raised position the vehicle would normally be driven on a road, to a rest position, in which rest position the vehicle would normally be carried in transit on said railway wagon, wherein the raised position and the rest position are at least 40cm, for example at least 65cm, apart.

The rest position typically is one in which the height difference between the tops of wheels and the underside of the vehicle body or chassis is minimal, i.e. is no greater than 100mm and. preferably is no greater than 50mm.

The road vehicle or vehicle chassis is preferably a trailer or trailer chassis and most preferably is of the straight frame chassis type.

The distance between the rest position and the raised position, in the case of a straight frame trailer chassis, will depend in part upon the height af the mounting, on a towing vehicle, to which the king pin or "fifth wheel" of the trailer is secured. With the towing vehicles currently in use, it would generally be necessary for the difference in height between the rest position and raised position to be at least 60cm, for example 65cm or more. If towing vehicles having substantially smaller wheels than is conventional, are used, then the required difference between the rest and raised positions may be consequently smaller.

The means for raising and lowering the trailer body or chassis between the rest position and the raised position advantageously comprises airspring means disposed between an axle mounting member to which an axle is secured, and an undersurface of the trailer body or chassis. The airspring means preferably takes the form of an air bag, of the general type known in conjunction with air suspension systems, but having a generally greater range of movement or "stroke". In general the airspring means will also function as the suspension system for the trailer.

The underside of the chassis may advantageously be cutaway or recessed to permit the chassis to be lowered further towards the wheels.

In a preferred embodiment, the invention provides a straight frame trailer chassis mounted on one or more sets of wheels disposed towards its rear end, said wheels having a radius no greater than 500mm; an air suspension system comprising air spring means disposed between an axle mounting member and the underside of the chassis; and means operable to inflate said airspring means to lift the chassis from a rest position, in which an adjacent section of the underside of the chassis is less than 100mm above the wheel, to a raised position, in which raised position the trailer chassis would normally be towed on a road, wherein the rest position and raised position are at least 60cm apart, preferably 65cm or more.

The references to the wheel radius as used herein mean the radius of the outer circumference of the tyres when inflated to their normal road-going pressures.

In another aspect, the invention provides a method of loading a road vehicle on to a railway wagon of the low loader type, the wagon having a wheel-mounted body comprising two end portions under which wheel bogies are located, and a central well portion which defines a load-bearing platform; the road vehicle having a load-carrying body or chassis mounted on one or more sets of wheels having a radius no greater than 500mm, the vehicle being provided with means for lowering the body from a raised position relative to the wheels, in which raised position the vehicle would normally be driven on a road, to a rest position (the rest position and raised position for example being at least 40cm and preferably 60cm apart); the method comprising moving said road vehicle onto the load-bearing platform of the railway wagon, and lowering the road vehicle from the raised position into its rest position so that the load-carrying body or chassis of the vehicle is supported by one or both of the two end portions of the railway wagon.

The road vehicle may be moved onto the load-bearing platform by virtue of being lifted thereon by a suitable hoist or crane, for example of a type similar to those known in relation to the lifting of freight-containers onto railway wagons. As an alternative, the load-bearing platform of the railway wagon may be provided with a chassis having the loadbearing platform rotatably mounted thereon, such that the road vehicle can be driven, towed or pushed onto the platform from a direction to the side of the wagon.

In one embodiment, the invention provides a method of loading a road vehicle, such as a road trailer, on to and from a railway wagon, which method comprises providing a railway wagon having a wheel-mounted chassis of the lowloader type, the chassis having a central well portion between two end portions under which wheel bogies are located; a load-bearing platform, and a turntable mounted between the load-bearing platform and the central well portion of the chassis; providing a road vehicle comprising a load carrying body or chassis mounted on one or more sets of wheels, said road vehicle being provided with means for lowering the body from a raised position, in which raised position the vehicle would normally be driven on a road, to a rest position ( the raised position and rest position being for example at least 40cm and preferably at least 60cm apart); said method of loading the road vehicle comprising the steps of:: (i) rotating the load-bearing platform of the railway wagon from a load-carrying position in which the longitudinal axis of the platform is aligned with the longitudinal axis of the wagon chassis, to a second position in which the platform axis is at an angle of up to 900 with respect to the chassis; (ii) moving the road vehicle from a direction to the side of the chassis on to the load-bearing platform; (iii) rotating the load-bearing platform of the railway wagon from the second position to the load-carrying position; and (iv) lowering the road vehicle body or chassis to its rest position such that a securing member or members on the vehicle body is or are lowered into contact with complimentary securing members on the railway wagon chassis, thereby to secure the vehicle to the wagon.

The road vehicle according to the invention typically is a road trailer of the type comprising a trailer body mounted towards its rear on two or more pairs of wheels, and having beneath its front end a king pin for engagement with a towing tractor.

The securing member on the trailer body or chassis may conveniently be the king pin, and the trailer may optionally be provided with further king pins or other securing members disposed beneath the lower surface of the trailer body or chassis.

The trailer body may be provided with one or more support legs, and these may be provided with means for raising and lowering the legs. Such means conveniently takes the form of an hydraulics system using the compressed air supply to the trailer.

The railway wagon, in conjunction with which the road trailers of the invention conveniently may be used, preferably have a load-bearing platform, the centre of rotation of which is preferably located towards or at the centre of the platform. The load-bearing platform on the railway wagon may be provided with ramps which can swing or fold down to enable the road vehicle to mount the platform, or such ramps may be provided separately.

The load bearing platform on the railway wagon may be rotatable with respect to the wagon chassis by virtue of the presence of a turntable positioned between the platform and the chassis. The turntable may have associated therewith its own drive mechanism, or the means for bringing about rotation of the load-bearing platform on the turntable may take the form of hydraulic rams mounted between the chassis and the platform.

In a further aspect, the invention provides a composite transport unit comprising a railway wagon (e.g. a railway wagon having a rotating load bearing platform) and a road vehicle of the type hereinbefore defined.

The invention will now be illustrated by reference to the non-limiting embodiments shown in Figures 1 to 7 in which: Figure 1 is a schematic side elevation of a road trailer according to one embodiment of the invention; Figure 2 is an enlarged schematic view of a part of the embodiment shown in figure 1; Figure 2a is an enlarged schematic view of the embodiment shown in Figure 2 but with the wheel omitted.

Figure 3 is an enlarged schematic view of a modification to the arrangement shown in Figure 2; Figure 4 is a schematic view of a compressed air system used in the embodiments shown in Figures 1 to 3; Figure 5 is a side elevation of the road trailer of Figures 1 to 4 mounted on a railway wagon; Figure 6 is a schematic plan view the embodiment shown in Figure 5; and Figure 7 is an enlarged sectional side elevation of the turntable shown in Figure 5.

As shown in Figure 1 it can be seen that a road trailer T according to one embodiment of the invention comprises a body 1 having a chassis 2 mounted on a set of three pairs of wheels 3 mounted on axles 4 of the low-loader type. By "lowloader axles" is meant mean axles fitted with smaller brake drums, hubs and tyres than are usually employed on road trailers. Preferably, the diameters of the tyres when inflated to their normal pressures are no greater than 80cm and most preferably are less than 76cm. One type of axle suitable for use with the trailers of the present invention is the Rubery Owen-Rockwell BMX axle fitted with 245 x 19.5 or 265 x 17.5 tyres.

The wheel axles 4 are mounted on suspension systems 5 (not shown) which are connected to the compressed air system of the trailer, as illustrated in Figure 4.

The road trailer T is provided on its underside at front and rear with king pins 6 and 7 respectively. King pin 6 normally engages the king pin mounting on a conventional towing vehicle or tractor. King pin 7 constitutes an extra securing means.

The trailer body is also provided with a pair of support legs 8 which can be raised or lowered hydraulically within a range of movement of 600mm up and down. As with the suspension systems 5, the support legs can be actuated from a control valve (not shown) on the side of the trailer.

At its rear end, the road trailer is provided with a pivotably mounted bumper and light bracket 9 which can be pivoted outwardly so that it is substantially flush with the under surface of the trailer body when the trailer is in transit on a railway wagon.

As can be seen from Figures 2 and 2a, the suspension system 5 comprises a double leaf spring suspension arm 10 linked at one end with the axle 51 by means of axle mounting 52 and at the other end to a pivot mounting 11.

A compressed air bag which may be for example a Rubery Owen Rockwell air suspension airspring but having a greater range of movement than conventional airsprings, is mounted between the axle 51 and the chassis 2 on the end 54 of the suspension arm 10. The airspring 53 is secured to the chassis by means of airspring pedestal 55 to which it is bolted and which in turn is welded to the chassis. The air bag is connected to the compressed air system of the trailer as can be seen in more detail in Figure 4. The use of air -bags in vehicle suspension systems is known but such air bags typically are constructed such that the maximum distance between raised (i.e. air bag inflated) and lowered (i.e. air bag deflated) of the vehicle body no greater than about 25cm.

In the present case, the air bag is constructed such that the maximum distance between raised and lowered positions of the vehicle body is at least 60cm, more preferably at least 65cm.

By providing an air bag having a much longer stroke than is found in conventional suspension systems, in combination with wheels of a much smaller diameter, the vehicle may be lowered much further as can be seen in Figure 2. Thus, in the normal road-going position (shown by means of the broken lines, the height of the lower surface 12 of the trailer above the ground, in this embodiment, is approximately 1.28 metres. When the suspension system is lowered to the rest position, the height of the surface 12 above the ground is approximately 806mm, a fall of 474mm.

The lower surface 12 of the trailer may advantageously be recessed to enable the suspension to be lowered still further, and such an arrangement is illustrated by the embodiment shown in Figure 3, on which a recess is provided at 13.

The compressed air system is illustrated in more detail in Figure 4 from which it can be seen that the system comprises linked reservoirs 14 and 15 isolated by means of pressure protection valve 16. The reservoirs can be charged to a pressure of 120 p.s.i. form a suitable external supply, via connection 22. Air line 17 leads to a control valve (not shown) on a control panel mounted on the side of the trailer.

Air line 18 leads from the control valve to the levelling valve 19, which controls access to the pairs of suspension systems 20 attached to each axle. Each individual suspension system comprises an air bag 21 which can be inflated to raise the suspension, or deflated to lower it. The precise construction and mode of operation of such a suspension system is known and need not be discussed further here.

Air reservoir 14 is also connected, via air line 23, to the brake system (not shown).

Figure 5, illustrates, schematically, a road trailer of the type shown in Figures 1 to 4 mounted on a railway wagon.

As shown in Figure 5 the rail wagon comprises a step-frame chassis 30 mounted at end positions 31 and 32 on wheel bogies 33 and 34. Between end portions 31 and 32 is a central well portion 35, the floor of which is at a height below the tops of the wheel bogies 33 and 34, as is conventional with stepframe chassis.

The wheel bogies 33 and 34, preferably are small wheeled bogies, wherein the wheels are less than 850mm in diameter.

Suitable commercially available bogies are the "Gloucester LTF 25" and Gloucester LTF 30" bogies available from Powell Duffryn Standard Limited, Cardiff, UK.

Mounted towards the centre of the low-lying portion 35 is a turntable 36. The turntable 36 may be of conventional construction, for example a turntable of the type known for use with cranes and like equipment. The construction of the turntable is illustrated in greater detail in Figure 7 from which it can be seen that the turntable comprises an inner cylindrical member 37 fixedly secured to the low-lying portion 35 of the chassis and an outer cylindrical member 38 mounted concentrically with the inner member 37 and being rotatable about the inner member, by virtue of roller bearings 39 attached to the lower edge of the skirt of member 37. A drive cog wheel 40 is located between inner and outer -cylindrical members and meshes with teeth around the inner surface of member 38 thereby to provide a means for rotating the outer member 38.As an alternative to the cog wheel, hydraulic rams could be employed.

Mounted on the turntable 36 is load-bearing platform 41.

Platform 41 may conveniently be formed from upper and lower steel plates 42 and 43 spaced apart by transverse I-beams 44 which function as reinforcing members. The "sandwich" structure is closed at either end by end plates not shown and at the side by side plates (also not shown). The construction of the platform is illustrated in Figure 7. In an alternative form of construction, the load-bearing platform could be, for example, in the form of a framework having parallel load-bearing members for supporting the wheels of the trailer, the parallel load-bearing members being linked by suitably disposed cross members.

The platform 41 is provided with side walls 45 (shown in phantom) along each of its longitudinal edges. The side walls 45 can be of box construction thereby to serve as reinforcing members. The platform may be provided with a central upstanding rib 48 (shown in phantom) for the purposes of improved structural rigidity. The embodiment illustrated in Figure 5 is intended especially for carrying unaccompanied trailers T. In this embodiment, the trailer T is secured to the wagon by means of securing means 46 which engage a complimentary securing member 7 on the trailer. The securing member 7 preferably is the king pin conventionally used to secure the trailer to its associated towing vehicle or tractor. The end 31 of the rail wagon may also be provided with means (not shown) for locking the trailer in place.The load-bearing platform 41 can be provided at either end with fold down ramps (not shown), so that the wagon can be used in a roll-on/rolls off mode. In the event that ramps are omitted, they may be provided as separate items, for example at the rail installation at which loading and unloading takes place. Alternatively, the rail installation where loading/unloading takes place may be equipped with fixed ramps or loading bays especially installed for the purpose.

In use, the load-bearing platform 41 of an empty wagon is rotated on the turntable 36 such that its longitudinal axis is at an angle of about 450 with respect to the longitudinal axis of the chassis 30 (see Figure 6). At such an angle, the ends of the platform 41 are clear of the chassis 30 and the ramps (not shown) at the ends of the platform 41 may be lowered therefrom onto the surrounding surface. Alternatively, separate ramps may be positioned against the ends of the chassis. A towing vehicle and its trailer T can then be driven onto the load-bearing platform until the trailer wheels 3 are wholly on the load-bearing platform 41. The towing vehicle is then uncoupled from the trailer, and then driven away from the trailer T. Prior to uncoupling the trailer T, it may be locked in place on the platform by means of suitable locking or securing means (not shown). Once the towing vehicle has been driven away from the trailer, the load-bearing platform 41 is rotated back to its load-carrying position, in which its longitudinal axis is aligned with the longitudinal axis of the chassis 1. A control valve (not shown) on the trailer body, which controls the flow of compressed air into and out of the suspension system, is then actuated to lower the trailer body 1 such that the king pins 6 and 7 come into contact with the securing means 46 and 49 on the chassis 2. The king pins are engaged by the securing means 46 and 49 to hold the trailer T in position on the load-bearing platform 41. If desired, the support leg 8 on the underside of the trailer T may be lowered to provide further support for the trailer.

When it is desired to unload the trailer from the railway wagon, the reverse sequence of steps is followed.

Thus the king pin 6 and 7 are released from the securing members 46 and 49 respectively and the suspension system of the road trailer T is actuated to lift the trailer body away from the wheels 3. When the trailer body has been raised, the load-bearing platform 41 is rotated on the turntable 36 such that its longitudinal axis is at an angle of about 450 with respect to the longitudinal axis of the chassis 2. The ramps are then lowered or put in place as required, and a towing vehicle tractor is then connected to the trailer. The trailer is then towed from the load-bearing platform, leaving the railway wagon empty for the loading of another trailer.

As an alternative to the method of loading the road trailer illustrated in Figure 5, the trailer of the type shown in Figures 1 to 4 may simply be lifted on to a conventional step-frame chassis (low-loader) railway wagon by means of a hoist or crane.

The advantages of the freight transporting system of the present invention are such that it enables full sized trailers to be carried on rail wagons thereby obviating the problems of reduced freight carrying capacity associated with current "piggy back" systems in use.

It will be apparent that numerous modifications and alterations may be made to the road trailer and railway wagon of the present invention without departing from the principles underlying the invention. All such modifications and alterations are intended to be embraced by this application.

Claims

1. A road vehicle suitable for carrying on a railway wagon of the low-loader type; the road vehicle comprising a load-carrying body mounted on one or more sets of wheels, the vehicle being provided with means for lowering the body from a raised position relative to the wheels, in which raised position the vehicle would normally be driven on a road, to a rest position, in which rest position the vehicle would normally be carried in transit on said railway wagon, wherein the raised position and the rest position are at least 40cm apart.

2. A road vehicle chassis mounted on one or more sets of wheels, the road vehicle chassis being provided with means for lowering the chassis from a raised position relative to the wheels, in which raised position the vehicle would normally be driven on a road, to a rest position, in which rest position the vehicle would normally be carried in transit on said railway wagon, wherein the raised position and the rest position are at least 40cm apart.

3. A road vehicle according to Claim 1 or a road vehicle chassis according to Claim 2 wherein the rest position is one in which the height difference between the tops of the wheels and the underside of the vehicle body or chassis is is no greater than 100mm.

4. A road vehicle or road vehicle chassis according to Claim 3 wherein the said height difference is no greater than 50mm.

5. A road vehicle or vehicle chassis according to any one of the preceding claims which is a trailer or trailer chassis and is of the straight frame chassis type.

6. A road vehicle or road vehicle chassis according to any one of the preceding claims wherein the means for raising and lowering the load-carrying body or chassis between the rest position and the raised position comprises airspring means disposed between an axle mounting member to which an axle is secured, and an undersurface of the trailer body or chassis.

7. A road vehicle or road vehicle chassis according to Claim 6 wherein the airspring means takes the form of an air bag.

8. A road vehicle or road vehicle chassis according to Claim 6 or Claim 7 which is a trailer or trailer chassis and wherein the airspring means also functions as the suspension system for the trailer.

9. A road vehicle or road vehicle chassis according to Claim 5 or Claim 8 wherein the underside of the chassis is cut-away or recessed to permit the chassis to be lowered further towards the wheels.

10. A straight frame trailer chassis mounted on one or more sets of wheels disposed towards its rear end, said wheels having a radius no greater than 500mm; an air suspension system comprising airspring means disposed between an axle mounting member and the underside of the chassis; and means operable to inflate said airspring means to lift the chassis from a rest position, in which an adjacent section of the underside of the chassis is less than 100mm above the wheel, to a raised position, in which raised position the trailer chassis would normally be towed on a road, wherein the rest position and raised position are at least 60cm apart, preferably 65cm or more.

11. A method of loading a road vehicle on to a railway wagon of the low loader type, the wagon having a wheelmounted body comprising two end portions under which wheel bogies are located, and a central well portion which defines a load-bearing platform; the road vehicle having a load-carrying body or chassis mounted on one or more sets of wheels having a radius no greater than 500mm, the vehicle being provided with means for lowering the body from a raised position relative to the wheels, in which raised position the vehicle would normally be driven on a road, to a rest position; the method comprising moving said road vehicle onto the load-bearing platform of the railway wagon, and lowering the road vehicle from the raised position into its rest position so that the loadcarrying body or chassis of the vehicle is supported by one or both of the two end portions of the railway wagon.

12. A method according to Claim 11 wherein the road vehicle is moved onto the load-bearing platform by virtue of being lifted thereon by a suitable hoist or crane.

13. A method according to Claim 11 wherein the loadbearing platform of the railway wagon is provided with a chassis having the load-bearing platform rotatably mounted thereon, such that the road vehicle can be driven, towed or pushed onto the platform from a direction to the side of the wagon.

14. A method of loading a road vehicle, such as a road trailer, on to and from a railway wagon, which method comprises providing a railway wagon having a wheel-mounted chassis of the low-loader type, the chassis having a central well portion between two end portions under which wheel bogies are located; a load-bearing platform, and a turntable mounted between the load-bearing platform and the central well portion of the chassis; providing a road vehicle comprising a load carrying body or chassis mounted on one or more sets of wheels, said road vehicle being provided with means for lowering the body from a raised position, in which raised position the vehicle would normally be driven on a road, to a rest position; said method of loading the road vehicle comprising the steps of: (i) rotating the load-bearing platform of the railway wagon from a load-carrying position in which the longitudinal axis of the platform is aligned with the longitudinal axis of the wagon chassis, to a second position in which the platform axis is at an angle of up to 900 with respect to the chassis; (ii) moving the road vehicle from a direction to the side of the chassis on to the load-bearing platform; (iii) rotating the load-bearing platform of the railway wagon from the second position to the loadcarrying position; and (iv) lowering the road vehicle body or chassis to its rest position such that a securing member or members on the vehicle body is or are lowered into contact with complimentary securing members on the railway wagon chassis, thereby to secure the vehicle to the wagon.

15. A method according to any one of Claims 11 to 14 wherein the said raised position and said rest position are at least 40cm apart.

16. A composite transport unit comprising a railway wagon (e.g. a railway wagon having a rotating load bearing platform) and a road vehicle of the type as defined in any one of Claims 1 to 10.

17. A road vehicle or road vehicle chassis substantially as described herein with reference to Figures 1 to 4.

18. A railway wagon substantially as described herein with reference to Figures 5 to 8.

19. A composite transport unit comprising a road vehicle and a railway wagon substantially as described herein with reference to the accompanying drawings.