GB2410225A

GB2410225A - Road and rail vehicle

Info

Publication number: GB2410225A
Application number: GB0401479A
Authority: GB
Inventors: Christopher Jolly
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-01-23
Filing date: 2004-01-23
Publication date: 2005-07-27
Also published as: GB0401479D0

Abstract

A vehicle with road wheels (12, 14, 16, 18) and also rail wheels (20, 22, 24, 26) wherein the rail wheels have flanges for engaging the outside of the rails and the sets of rail wheels on each side of the vehicle can be raised and lowered independently. This allows the vehicle to pass over rail points irrespective of their setting.

Description

ROAD AND RAIL VEHICLE

The present invention relates to a vehicle capable of travailing on road and on rails, and more particularly to a vehicle which can take a desired path at points, regardless of how the points are set.

Road vehicles, which can be steered by a driver, are of course well-known, and will not be described further. Similarly, rail vehicles for travailing on the permanent way are well-known. The rail vehicles have flanged wheels, the flanges of which engage on the inner edges of the rails. These flanges allow the direction of the rail vehicle to be changed at points, as will now be described with reference to Figures 1 and 2.

Figures 1 and 2 show schematically how a set of points operate with a conventional rail vehicle. The points comprise an approach branch A with left-hand and right-hand approach rails 1 and 2, along which a vehicle approaches. Depending on the setting of the points, a vehicle can be directed along the left branch L (which comprises left-hand rail 5 and right-hand rail 6), or along the right branch R (which comprises lefthand rail 7 and right-hand rail 8). The setting of the points is changed by moving the point rails 3 and 4. The other rails are fixed.

In Figure 1, the points are set so that a vehicle approaching the points (from the bottom of the page) will be directed along the left branch, and in Figure 2, the points are set so that the vehicle will be directed along the right branch.

When a vehicle approaches the points when they are ', set as shown in Figure 1, the flanges of the rail wheels,4 are in contact with the inner edges of approach rails 1 and 2. When the wheels reach the point rails, the flange on the left-hand wheel fits through the gap between the lefthand rail 5 of the left branch L and the left point rail 3. However, the flange of the right-hand wheel comes into contact with the right point rail 4, and is forced to move along the right point rail. The vehicle is thus directed along the left branch L. When the points are set as in Figure 2, the opposite action occurs. The flange on the right-hand wheel now passes through the gap between the right-hand rail 8 of the right branch R and the right point rail 4, while the flange of the left-hand wheel comes into contact with the left point rail 3, and is forced along this rail. The vehicle is thus directed along the right branch R. Vehicles which can travel on road and rail are also known. In one form, a conventional road-going vehicle (with road wheels) is modified by having flanged rail wheels attached to the front and rear of the vehicle.

These wheels are for engaging with the rails, and can be raised or lowered depending on how the vehicle is to be used.

For road operation, the rail wheels are held in a raised position, and the vehicle is driven normally, with the road wheels in contact with the road to provide drive and steering. For rail operation, the rail wheels are lowered to engage with the rails (in the same manner as the wheels on conventional rail vehicles). The road wheels rest on the rails (or the ground) to provide a source of motive power for the vehicle, and the vehicle is "steered" by changing the setting of points, as for a conventional rail vehicle. Vehicles of this type are commonly used for maintenance of the railway.

A disadvantage of this type of vehicle is that, when running on rails, it is forced to follow the path laid out for it. If the vehicle comes to a set of points, then it must go in the direction that the points are set to. If this is not the desired direction, then the setting of the points must be changed, which will in practice require communication between the driver of the vehicle and signalling staff. This can significantly lengthen journey times.

It would be desirable if the vehicle could take either branch at points, regardless of the setting of the points. This would not only reduce journey time, but would also provide the possibility of automatic operation, in which there is no signalling or dynamic control from the permanent way itself.

According to the invention, there is provided a vehicle with road wheels and rail wheels, wherein the rail wheels have flanges for engaging the outside of the rails, and the sets of rail wheels on each side of the vehicle can be raised and lowered independently.

Such a vehicle can operated so that it can take either branch at a set of points, regardless of how the points are set. If the right-hand set of rail wheels are raised, while the left-hand set of rail wheels continue to engage the rail, then the vehicle will take the left branch, no matter how the points are set.

Similarly, if the right-hand set of rail wheels are raised, with the lefthand set of rail wheels continuing to engage the rail, the vehicle will take the right branch.

Preferably, the vehicle is provided with means to prevent sideways motion with respect to the rails when one set of rail wheels is raised.

During normal running of the vehicle, sideways motion is prevented by engagement of the flanges of the rail wheels with the outer edges of the rails. However, when one set of rail wheels are lifted, the flanges on that side are no longer in contact with the rails, and so the vehicle can move sideways, towards the side where the rail wheels are still in contact, which risks derailment. This problem is avoided by providing means to prevent this sideways motion.

In a preferred form, the means to prevent sideways motion take the form of further wheels, which are lowered to engage with the rail on one side of the - 4 vehicle when the rail wheels on the other side of the vehicle are raised. In a further preferred form, these further wheels are in the form of cylinders whose axes are skewed relative to the axes of the road wheels and rail wheels, such that the inner end of the axis of the further wheel is located further forward than the outer end of the axis of the further wheel.

A preferred embodiment of the invention will now be described by way of example only and with reference to the accompanying drawings, in which: Figure 1 is a schematic illustration of a set of points, set in a first position; Figure 2 is a schematic illustration of the same set of points, set in a second position; Figure 3 is a schematic plan view of the wheels of a first embodiment of a vehicle in accordance with the invention; Figure 4 is a schematic view (from the right-hand side of the vehicle) of the wheels of the vehicle when running on straight rails; and Figure 5 is a schematic view (from the right-hand side of the vehicle) of the wheels of the vehicle when taking the left branch at a set of points.

Figure 3 shows schematically the arrangement of wheels of a preferred embodiment of the vehicle in accordance with the current invention. The direction of travel of the vehicle is indicated by arrow D. As can be seen, the vehicle has four road wheels 12, 14, 16, 18, conventionally arranged at the corners of the body.

It also has two front rail wheels 20, 22, positioned ahead of the front road wheels, and two rear rail wheels 24, 26, positioned behind the rear road wheels. In addition, the vehicle has further wheels 28, 30 (hereinafter referred to as offset wheels), positioned ahead of the front rail wheels, whose purpose will be described in more detail later.

In a conventional rail vehicle, the flanges of the rail wheels are arranged so that they contact the inner - 5 - side of the rails. However, in this embodiment, the rail wheels 20, 22, 24, 26 are arranged so that the flanges contact the outer side of the rails.

The body of the vehicle, which is not shown, is provided with means for raising and lowering the rail wheels so that they can be brought into and out of contact with the rails. These means are capable of raising the left-hand pair of rail wheels and the right- hand pair of rail wheels independently of each other.

The body of the vehicle is also provided with means for raising and lowering the offset wheels so that they can be brought into and out of contact with the rails.

Again, the left-hand offset wheel and the right-hand offset wheel can be raised and lowered independently.

Normal operation of the vehicle, on a straight (unbranched) section of permanent way, will now be described with reference to Figure 4. Again, the direction of travel is indicated by the arrow D. As can be seen, the road wheels 12, 14, 16, 18 are in contact with the rails, and provide motive power for the vehicle.

Further, all four rail wheels 20, 22, 24, 26 are in their lowered position, in contact with the rails. The flanges contact the outer sides of the rails; the flanges of the left-hand rail wheels 20, 24 are partially hidden by the rails, and are shown in dotted lines. The offset wheels 28, 30 are raised, and do not contact the rails.

During normal operation, the vehicle operates in the same manner as a prior art road/rail vehicle. The vehicle is driven forward by the road wheels 12, 14, 16, 18, and is kept aligned on the rails by the flanges of the rail wheels 20, 22, 24, 26.

However, operation of the vehicle differs considerably from that of a conventional road/rail vehicle when the vehicle encounters a set of points. As described above, a conventional road/rail vehicle, whose rail wheels have flanges that contact the inner sides of

I - 6

the rails, is forced to follow the setting of the points, in the same way as a conventional rail vehicle.

In contrast, the vehicle of the present invention can proceed down either branch line, irrespective of the setting of the points.

Figure 5 shows how the vehicle is operated when it is desired to travel down the left-hand branch. The right-hand pair of rail wheels 22, 26 are raised so that the lowermost parts of the flanges are above the uppermost part of the rails. The left-hand pair of rail wheels 20, 24 remain in contact with the permanent way.

Further, the left-hand offset wheel 28 is lowered, so that it comes into contact with the rail. The right- hand offset wheel 30 remains in a raised position. The road wheels 12, 14, 16, 18 are neither raised or lowered, and remain in their original position.

The vehicle is then driven forward, using the road wheels. The flanges of the left-hand pair of rail wheels 20, 24 will remain in contact with the outer side of the left-hand rail as the vehicle passes over the points. It will be seen from Figures 1 and 2 that the outer edge of the left-hand rail is continuous between the entry and the exit to the points, and the contact of the flanges of the rail wheels 20, 24 on this continuous edge will guide the vehicle to the left. Further, as the right-hand pair of rail wheels 22, 26 have been lifted, they will not come into contact with any of the rails (fixed or movable) of the points, and so will not interfere in the guiding of the vehicle towards the left by the left-hand pair of rail wheels. Thus, the vehicle will be guided onto the left branch, regardless of whether the points are set to direct conventional rail vehicles to the right or to the left.

Once the vehicle has passed the points, the right hand rail wheels 22, 26 can be lowered again, so that they come into contact with the rails. The vehicle can then be driven as before, with the flanges serving to keep the vehicle aligned on the permanent way. / - 7 -

It will be appreciated that, since only the flanges of the left-hand pair of rail wheels 20, 24 are in contact with the rails when the vehicle passes through the set of points, sideways motion of the vehicle towards the left will tend to push it off the rails.

The offset wheels 28, 30 are provided to ensure that the vehicle cannot move sideways in this way when it passes through sets of points.

In the form shown in Figure 3, the offset wheels 28, 30 are generally cylindrical, with the axis of rotation of the cylinders being slightly skewed relative to the axes of rotation of the road and rail wheels.

Further, the direction of skew is such that the inner ends of the offset wheels are disposed further forward than the outer ends of the offset wheels.

The offset wheels are not powered, and each wheel is driven to rotate by friction between it and the rail as the vehicle moves forward. Sideways motion of the vehicle will be prevented by friction between the offset wheel and the rail.

The offset wheel only needs to be used when the vehicle is passing through points; normally, sideways motion of the vehicle is prevented by the flanges of the rail wheels coming into contact with the rails, and so the offset wheels are normally raised above the rails.

It will be appreciated that the offset wheels may take various forms; however, it is important that no part of the offset wheel projects below the upper surface of the rail, to ensure that the offset wheel does not come into contact with the movable points rails when the vehicle passes through a set of points.

As the road/rail vehicle described herein is capable of deciding its own route when it encounters a set of points (by raising one of the pairs of rail wheels as appropriate), there is no need for contact between the driver of the vehicle and signalling staff, as is necessary with conventional road/rail vehicles having rail wheels with flanges that contact the inside of the rails.

Indeed, it is conceivable that the road/rail vehicle described herein could be operated without a driver, for example using an onboard computer which has the desired route programmed into its memory and which can raise and lower the wheels as required to allow the vehicle to follow the desired route through various sets of points. - 9

Claims

1. A vehicle with road wheels and rail wheels, wherein the rail wheels have flanges for engaging the outside of the rails, and the sets of rail wheels on each side of the vehicle can be raised and lowered independently.

2. A vehicle as claimed in claim 1, provided with means to prevent sideways motion with respect to the rails when one set of rail wheels is raised.

3. A vehicle as claimed in claim 2, wherein the means to prevent sideways motion take the form of further wheels, which are in the form of cylinders whose axes are skewed relative to the axes of the road wheels and rail wheels, such that the inner end of the axis of the further wheel is located further forward than the outer end of the axis of the further wheel.