1 IMPROVEMENTS TO BARRIER FENCES 5 TECHNICAL FIELD This innovation concerns improved apparatus and methods for anchoring to a ground mass a barrier fence that may be used in any of several laterally spaced apart positions, and must be able to be moved between one such position and another. In particular, the innovation relates to 10 fences that define boundaries of racetracks such as are used in the sport of horse racing. BACKGROUND ART In the sport of horse racing, elongate fences are provided to act as boundaries of the actual courses on which the horses race. It is desirable that 15 such fences be able to be installed and relocated reasonably easily, and most importantly that they present the smallest possible hazard to horses and jockeys in the event of one or more of them falling. Barrier fences have been developed for horse- and other racing applications but have not always performed well in these respects. 20 In international patent application No. PCT/AU2007/001343 filed on 12 September 2007, there are disclosed certain barrier fences that are believed reasonably easy to install, to remove, to relocate and to repair, and that can be designed to restrict the potential for harm to horses and jockeys in the event of a fall or other accident. Specifically such barrier fences have the 25 ability for uprights to separate from ground anchors at their lower ends under impact loads from falling animals and/or jockeys. The as-filed specification of that application (published on 20 March 2008 under the designation WO 2008/031150 Al) is hereby explicitly incorporated in the present specification, in its entirety, by reference. 30 In international patent application No. PCT/IB2008/003282 filed on 1 December 2008, there are disclosed certain improvements to barrier fences including particularly barrier fences such as those disclosed in WO 2008/031150 Al. The as-filed specification of this second application, published as WO 2009/068984, Al is hereby explicitly incorporated in the 35 present specification, in its entirety, by reference. The improvements include 2 apparatus and methods for installing a barrier fence in a first position such that after being removed to a second position the barrier fence can be re installed in the first position in a reasonably convenient way. In particular the apparatus and methods can be used for barrier fences having upright 5 members that are securable to ground anchor means intended to be driven into a ground mass. Disclosed herein are still further improvements mentioned in the previous paragraph, that are believed to offer time savings and improved convenience for users of such barrier fences, at least in certain 10 circumstances. The innovations claimed herein are believed suitable for application to the barrier fences as described in the two mentioned PCT applications which have a facility for uprights to separate from their ground anchor means under impact loads. The references herein to two PCT applications and their international 15 publications are not intended as admissions that the contents of either have at the date of filing of the present application become part of the common general knowledge in the arts of barrier fence design and use in Australia or elsewhere. DISCLOSURE OF INNOVATION 20 What is claimed here as an innovation is, in a first aspect, a barrier fence for a race track movable between a first position and other positions on a ground mass, said barrier fence comprising an elongate rail and uprights secured thereto at positions along the rail, wherein: (a) a said upright is secured at an upper end thereof to the rail 25 and at a lower end thereof to a ground anchor; (b) in use of the barrier fence said lower end of said upright is releasable from said ground anchor in response to application to the upright of an impact load; and (c) said ground anchor comprises a lower section that is received 30 and held in an internal space of a footing positioned within the ground mass when the barrier fence is in a first position and that is removable from said internal space and driveable into the ground mass thereby to be secured within the ground 3 mass for use when the barrier fence is in positions other than the first position. In a preferred embodiment, the footing comprises.an elongate tubular member and in use of the footing the lower section of the ground anchor is 5 received within the tubular member. More preferably, the footing further comprises a cap means that is secured to and partially closes an upper end of the elongate tubular member and through which the lower section of the ground anchor passes in use of the footing to hold the ground anchor. 10 In a further aspect, the innovation provides a method for providing a race track barrier fence in a first position on a ground mass and enabling movement of the barrier fence between the first position and other positions, the method including the steps of: (a) providing a barrier fence assembly including an elongate rail and 15 uprights secured at upper ends thereof to said rail at positions along the rail; (b) providing at least one ground anchor to which a lower end of said upright is securable and comprising a lower section that can be driven into the ground mass and thereby secured therein, the 20 ground anchor being adapted to release said upright in response to an impact load applied to said upright; (c) securing a footing within the ground mass so that said lower section of said ground anchor is receivable in an internal space of the footing to be held therein when the barrier fence is in the 25 first position, the footing being adapted to enable withdrawal of said lower section therefrom so that said ground anchor lower section can be driven into the ground mass where and when required for the barrier fence to be in a said other position; and (d) securing said lower end of said upright releasably onto said 30 ground anchor. Preferably the method is further characterized in that: (a) the footing in use comprises an elongate tubular member and the step of securing said footing within the ground mass includes driving said elongate tubular member into the ground mass; and 4 (b) in use of the footing when the fence in the first position the lower section of the ground anchor is received within said tubular member. Note that throughout this specification, the word "comprise" and words 5 derived therefrom such as "comprising" and "comprised", when used in relation to a set of integers elements or steps are to be taken as indicating that the elements integers or steps are present but not to be taken as precluding the possible presence of other elements integers or steps. BRIEF DESCRIPTION OF DRAWINGS 10 Figure 1 is a perspective view of a barrier fence of a type used in horse racing courses shown in a preferred position and in chain dotted lines in a possible alternative position; Figure 2 is an end view of the barrier fence shown in Figure 1, showing a ground mass in cross-section; 15 Figure 3 is an elevation (looking in the same direction as in Figure 2 of a portion of an upright, and a ground anchor of the fence shown in Figure 2; Figure 4 is a sectional view of the assembly shown in Figure 3, the section being taken at station 4-4, with some lines omitted for clarity; Figure 5 is a sectional view of the assembly shown in Figure 3, the 20 section being taken at station 5-5, with some lines omitted for clarity; Figure 6 is a perspective view of a portion of a support means according to the innovation and a driving tool therefor; Figure 7 is a perspective view of the driving tool shown in Figure 6; Figure 8 is a perspective view of a ground anchor as used in the fence 25 shown in Figure 1, being assembled to a support means therefor according to the innovation; Figure 9 is an end view of a barrier fence with a ground anchor supported by a support means according to the innovation; Figure 10 is an end view of a barrier fence with a ground anchor 30 supported by a further support means according to the innovation; Figure 11 is a perspective view, showing a top surface, of a cap for use in the further support means shown in Figure 10; Figure 12 is a further perspective view of the cap shown in Figure 11; 5 Figure 13 is a view looking in the direction of arrow "A" of the cap as shown in Figure 12; Figure 14 is a view looking in the direction of arrow "B" of the cap as shown in Figure 11; 5 Figure 15 is a cross-sectional view of the cap as shown in Figure 14, the section being taken at station 15-15, with a ground anchor lower part and support means tube also shown; Figure 16 is a cross-sectional view of the cap as shown in Figure 15, the section being taken at station 16-16, portions of a ground anchor lower 10 part and a support means tube also being shown, and some lines not present in the sectioning plane being omitted; Figure 17 is a perspective view of the cap shown in Figure 15 including portions only of a ground anchor lower part and support means tube; Figure 18 is a perspective view of a barrier fence ground anchor usable 15 with footings as shown in Figures 19 and 20; Figure 19 is a perspective view of a set of footings let into a ground surface and a ground anchor positioned above one such footing; Figure 20 is a vertical cross-sectional view of one of the footings shown in Figure 19, the section being taken at station "54 - 54" of Figure 19; 20 Figure 21 is an end view (looking in the direction of arrow "Z") of a barrier fence portion as shown in Figure 25, showing a ground mass in vertical cross-section; Figure 22 is a side elevation of a ground anchoring arrangement usable with the innovation; 25 Figure 23 is a cross-sectional view taken at station "26-26" in Figure 22; Figure 24 is a cross-sectional view taken at station "27-27" in Figure 22; Figure 25 is a plan view of a fence portion using the arrangement 30 shown in Figure 22. DETAILED DESCRIPTION Figure 1 shows a portion of a barrier fence 1 of a type used in horse racing courses to bound and delineate the course the horses are to follow when running. Barrier fence 1 is shown mainly in full lines at (a) in a preferred 6 or normal position and in chain-dotted lines in a possible alternative position (b). It is known in horse racing to alter the length or layout of a course by moving portions of their barrier fences (such as 1). Barrier fence 1 comprises an elongate rail 2 that is continuous and 5 formed by joining separate continuous lengths of a suitable plastics extrusion. (Other materials such as steel are also used for rails.) Rail 2 is supported by a number of longitudinally spaced-apart uprights or posts 3. The uprights 3 are supported on the surface 4 of a ground mass 5 by means of suitable ground anchors 6 let into the ground mass 5. Figure 2 10 shows the rail 2 in transverse cross-section with one upright 3 and its associated ground anchor 6. Ground anchor 6 has a platelike upper part 7 to which a lower end of an upright 3 is releasably secured and a sharp-edged lower part 8 adapted to be pushed hammered or otherwise driven into a ground mass 5 of earth (typically grassed on its surface 4). 15 The ground anchors 6 can be driven into ground surface 4 at suitable positions to locate barrier fence 1 in position (a) or position (b) (or any other required position). If (a) is a normal or preferred position, used repeatedly, this can involve significant time and effort and possibly damage to the ground surface 4. One solution set out in WO 2009/068984 is to provide concrete (or 20 concrete and steel) footings in positions corresponding to fence position (a). This approach will be described herein together with another approach disclosed in Australian standard patent application No. 2011201407. The particular ground anchor 6 shown in Figures 1, 2, 3, 4 and 5 is generally of a type intended to allow separation of an upright 3 from its 25 associated ground anchor 6 under impact loads. Such ground anchors are described in the aforementioned publication WO 2009/068984, by reference particularly to Figures 25 - 29 of that publication (ground anchor there numbered 201). Ground anchor 6 is in its arrangement and principle of operation similar to the ground anchor numbered 201 in WO 2009/068984, 30 and there follows a description derived from that publication of a fence 218 incorporating the ground anchor 201. Figures 25, 26, 27, 28 and 29 of WO 2009/068984 correspond respectively to Figures 22, 23, 24, 25 and 21 of the present specification.
7 Refer firstly to Figure 25. Barrier fence 218 has a continuous elongate rail assembly 219 supported by uprights 220 and has ground anchors 201. Figure 25 shows in plan view a portion of barrier fence 218 comprising rail assembly 219 and an upright 220 secured to rail assembly 2. The bottom 5 end of an arcuately bent tube 221 of upright 220 is received on stub 207 of a fitting 205, and fitting 205 is mounted to a ground anchor 201 that is described below. Line 222 lies in the plane that contains the axis of tube 221 and so is normal to the length of rail assembly 219. Figure 22 shows a ground anchor assembly 201 having a lower section 10 202, with sharpened lower edge 203 that is adapted to be driven into the ground, and a top plate 204. Lower section 202 may be of any suitable cross sectional shape and is shown (see phantom lines in Figure 24 only) as being formed of hot-rolled steel equal angle in an orientation that enhances the resistance of ground anchor to overturning in the ground under rearwardly 15 directed sideloads applied to rail assembly 219. Anchor 201 is able to be driven into the ground, so that plate 204 is close to, approximately flush with or bearing against, the ground surface. Secured to ground anchor 201 is a bottom fitting 205. Fitting 205 has a plate 206 that in use sits above and bears against plate 204, and an 20 upstanding stub 207 that fits into a lower end of a tubular upright member 208 (similar to tube 12). Fitting 205 has an optional hole 217 extending through it, coaxially with stub 207. Plate 206 is held in place by two formations 209 and 210 that are secured to top plate 204. Also to enhance the resistance of ground anchor 201 to overturning in 25 the ground under rearwardly directed sideloads applied to rail assembly 219, plate 204 has a rearwardly directed extension 703 whose lower surface abuts the ground. Formation 209 has an upstanding pin 211 and a plate 212 that is secured to an upper end of pin 211. Plate 206 fits snugly between plates 212 30 and 204. Pin 211 is "matingly" received in a recess 216 in plate 206. The word "matingly" as used here is described below. Formation 210 has an upstanding pin 213 and a plate 214 that is secured to an upper end of pin 213. Plate 206 also fits snugly between plates 204 and 214. Plate 206 has a shallow recess (dimple) 215 that is shaped to matingly accommodate a portion of pin 213.
8 The shapes and proportions of pins 211 and 213, recess 216 and dimple 215 are such that plate 206 is held snap-fittingly by and between pins 211 and 213 with substantially no free play, but such that plate 206 can be dislodged by urging it with a comparatively small force in a direction perpendicular to a line 5 222 between pins 211 and 213, compared to the large force which would be required to move plate 206 along line 222. Turning to use of the word "matingly" above, it will be noted that where pin 211 is received in recess 216, there is a clearance 701 on centerline 222 so that pin 211 bears against only the sides of recess 216. This is to ensure 10 that when plate 206 is pushed into place between pins 211 and 213, plate 206 is slightly under compression. This has been found desirable to enhance the snap-fitting retention and subsequent release of plate 206 between pins 211 and 213. It has also been found desirable that tube 221 be able to rotate about 15 the longitudinal axis 700 of stub 207. This aids in positioning plate 206 in engagement with ground anchor 201 and in obtaining its satisfactory release also. In response to a horizontal load (represented by vector 223) applied in a rearward direction to the rail assembly 219, tube 221 bends as required, but 20 plate 206 of fitting 205 is held very securely between pins 211 and 213 and between plates 204 and both 212 and 214. Vector 223 is representative of a load that might be applied by a horse nudging rail assembly 219 for example. Plate 212 acts to prevent rotation of plate 206 under such loads 223, as plate 206 is urged upwardly against plate 212 under such Ioads. 25 However, a horizontal load 227 applied directly to upright 220 or fitting 205, for example by a jockey falling underneath rail assembly 219 has an effect that depends on the direction of the impact. It has been found that if such a load is in the direction of line 222 (as seen in Figure 25) or within a certain angular range (represented by arrow 224) that includes line 222 and 30 extends on either side of line 222, then fitting 205 will remain in place. But if the horizontal load on upright 220 is directed within either of the ranges represented by arrows 225 and 226, it has been found that fitting 205 will slide off ground anchor 201, so minimizing the chance of injury to the jockey. The 9 ranges 224, 225 and 226 can be influenced by the design of fitting 205 and ground anchor 201. Thus, barrier fence 218 can be designed to be very secure against actual carrying away of lower ends of uprights 220 in response to likely loads 5 on rail assembly 219, but with those lower ends being able to carry away under loads applied to uprights 220 for example by riders (or horses) falling underneath rail assembly 219. It will be noted that the presence of both ranges 225 and 226 allows racing in both directions along fence assembly 218. (On the other hand, there is no necessity for line 222 to be perpendicular 10 to the length of rail assembly 219, and a different orientation may be preferable if racing is normally in one direction only). Instead of dimple 215, plate 206 could have other types of formation to engage pin 213. Note that the junction between stub 207 and plate 206 may be filleted 15 as shown, optionally including having a larger radius fillet facing plate 212 and a smaller radius fillet facing plate 214 to avoid stub 217 itself failing there under impact loads. Measures are preferably provided to enable predictable carrying away under loads not applied to upright 220 in the angle ranges 225 or 226. As a specific example, a groove 702 may be provided at the base of 20 stub 207 as a "weak point" so that under large side loads applied rearwardly (as load 223) to rail assembly 219 it is possible for tube 221 and stub 207 of the upright 220 to separate from fitting 205 and ground anchor 201. The load 223 at which this occurs can be chosen quite independently of the impact load on upright 220 at which plate 206 is released from between pins 211 and 213. 25 It is desirable if stub 207 does break that it be retained in the lower end of tube 221 to avoid becoming hazardous to riders or horses. Although not shown, it is possible to provide for this. For example a pin or screw could be arranged to pass through one wall of tube 221 with an end of the pin or screw being received in another groove in stub 207 so as to prevent lengthwise 30 movement of stub 207 in tube 221. WO 2009/068984 discloses one solution to the problem of easing relocation of barrier fences having ground anchors such as 201. This will now be described here, by reference to Figures 18, 19, 20 and 21, which 10 correspond to Figures 52, 53 and 54 respectively of WO 2009/068984, and using fence 218 as an example of such a barrier fence. It is important to the correct functioning of fence 218 when it is subject to impact that ground anchors 201 be correctly oriented relative to the rail 5 assembly 219. When ground anchors 201 are being driven into a ground mass 1121, it is therefore necessary to use care in the positioning of footings 201. Referring to Figure 19, there is shown a ground surface 1121, provided with a row of concrete footings 1123 let into the surface 1121. Each footing 10 1123 has a hole 1125 so shaped sized and oriented that the lower section (spike portion) 202 of a ground anchor 201 can be received therein, and be held in a correct orientation for the fence 218. Line 1132 represents a line along which the footings 201 are to be arrayed in a preferred position of fence 218. 15 Hole 1125 can optionally (but preferably) be defined by provision of a tube 1131 in footing 1123. A square tube 1131 can suit the spike shape shown on ground anchor 201. More generally, the hole 1125 in a footing 1123 provided according to this aspect of the innovation can be any shape suitable for holding a depending part of a footing in its correct orientation. 20 Although not shown, a simple cap (eg of plastics material) may be provided for each footing to close hole 1125 when the footing is not in use. Erection of fence 218 in its preferred position is simplified by the fact that ground anchors 201 can simply be dropped into place in each footing 1123 and the uprights 220 attached to them. When the fence 218 is to be 25 moved to another position, the ground anchors 201 can be lifted out of holes 1125, and either driven into the ground as spikes (if footings like footings 1123 are not available in the new position) or dropped into similar footings 1123 in the new position if these are available. There will now be described a further approach to the problem of 30 easing relocation of barrier fences having ground anchors such as 201, and limiting ground damage in preferred positions of such fences. This further approach is disclosed in Australian standard patent application No. 2011201407. The description will be given by reference to barrier fence 1 having uprights 3 and ground anchors 6.
11 Plate 7 and lower part 8 of ground anchor 6 correspond respectively to the plate numbered 204 and the lower section 202 of ground anchor 201. Although the same in its essentials as ground anchor 201, and able to be driven into ground surface 4 at suitable positions to locate barrier fence 1 in 5 position (a) or position (b) (or any other required position),.ground anchor 6 does have two differences. The first is that the formations 9 and 10 of ground anchor 6 (corresponding to parts 211/212 and 213/214 of the ground anchor 201) are secured by nuts 11 and 12 on bolts within formations 9 and 10. The second difference is that lower part 8 is not formed from hot-rolled 10 equal angle with (in cross-section) arms at 90 degrees to each other, but bent from flat plate at a more obtuse angle - see Figure 5. However, the possibility of lower part 8 being of hot rolled equal angle, or some other suitable section, is not precluded. Figure 6 shows an elongate tube 20 of non-circular cross-section, 15 chosen so that the lower part 8 of a ground anchor 6 can fit slidingly in its internal volume 21. A triangular tube 20 is shown, and is sized and suited to receive the chevron-shaped cross-section of part 8, as shown in Figure 5, with part 8 being unable to rotate within tube 20. Also shown in Figure 6 is a driving tool 22 which has a portion 24 of triangular cross-sectional shape that 20 can be slid into, and be received close-fittingly in, the internal volume 21 of tube 8. Tool 22 has an upper part 23 that in use is mountable to a vibratory hammer (eg a so-called "Kango" hammer) and between upper part 23 and portion 24 a section 31 with a shoulder 25 that in use is held against an end face 26 of tube 8. Lower end 27 of tool 22 is tapered to ease its passage into 25 a ground mass such as ground mass 5. To provide a supporting means in ground mass 5 for ground anchor 6, tube 20 is firstly slid over portion 24 of tool 22 until face 26 abuts shoulder 25, as shown by arrow 30, and the hammer (not shown) is used to drive tool 22 and tube 20 with it, downwardly into ground mass 5 from its surface 4. Portion 30 24 of tool 22 prevents internal volume 21 of tube 8 filling with soil- When tube 20 has been planted sufficiently far into ground mass 5, tool 22 is simply withdrawn leaving tube 20 behind. Being of non-circular cross-section externally as well as internally, tube 20 is prevented from rotating about a vertical axis in use of barrier fence 1 as is desired with a fence of its type.
12 Compared for example to the provision of concrete footings, this is a rapid and easy process, which is advantageous when many ground anchors 6 must be supported. Figure 7 shows another view of tool 22. 5 Figure 8 shows the situation after tube 20 has been driven downwardly (substantially vertically) into ground surface 4 in this way, and tool 22 withdrawn. Tube 20 protrudes slightly from surface 4. The lower part 8 of ground anchor 6 is simply slid downwardly in the direction of arrow 32 into the internal volume 21 of tube 20 from above. An upright 3 can then be secured to 10 ground anchor 6. It is of course important that when the fence 1 is of a type (as here) where orientation of ground anchors is important, that tubes 20 be correctly oriented when being driven into ground mass 5. The tube 20 supports the ground anchor 6 when in place and so may be termed a support means for ground anchor 6. 15 Figure 9 is comparable with Figure 2 and shows a fence 2071 which is the result of this way of providing a support means for ground anchor 6. This approach eliminates the need to push hammer or otherwise drive ground anchors 6 directly into ground mass 5 every time the barrier fence 1 is to be positioned in the position (a), and the ground damge that can occur 20 when that is done numerous times. Nevertheless, there are some disadvantages to this arrangement. The upper ends of tube 20, being close to ground surface 4, can be difficult to see, especially as racetrack grass is often quite long, potentially wasting some time during fence relocation work, and can present a tripping hazard. Debris can 25 also enter tubes 20 which is undesirable unless caps of some sort (not shown) are used to close tubes 20. Such caps would have to be stored when not in place and would be vulnerable to loss. Easy finding of tubes 20 is not only important when they are to be used for accommodating ground anchors 6, but also when erecting fence 1 in another position, as the original line of 30 fixed ground anchor positions serves as a datum for positioning the fence 1 in such another position. Accordingly, it is preferred to provide a cap that is fixed to the upper end of each tube 20, and in a preferred embodiment of the innovation this is done. Figure 10 is comparable with Figures 2 and 9 and shows fence 2081 13 generally similar to fence 1 in cross-section, but with a ground anchor 6 held in a support means 40. Support means 40 comprises the tube 20 and a cap 42 secured thereto at an upper end. Support means 40 is installed by hammering pushing or otherwise driving tube 20 into place as described 5 above, and then securing cap 42 to the upper end of tube 20. Alternatively, and also within the scope of the innovation is to provide a cap (not shown) that is suitable to be first attached to tube 20 and hammered pushed or otherwise driven into position with it as a single unit. Cap 42 is shown in Figures 11 - 17 and is shown as being formed in 10 one piece. This is preferably done by moulding in a suitable plastics material such as PVC, although this is not to preclude other suitable methods and materials being chosen. Cap 42 has a wall 44 with a top surface 46, and a peripheral stiffening flange 48 depending (i.e. extending in a direction that in use of cap 42 is downward) from a bevelled outer portion 43 of wall 44. In use 15 of cap 42, the lower surface 13 of plate 7 of ground anchor 6 abuts an upper surface 46 of wall 44. Depending from a lower surface 50 of wall 44 is a short tubular formation 52 having an inner surface 54 that is generally triangular. Also depending from lower surface 50 is a second formation 56 with an outer surface 58 that is triangular. Stiffening ribs 60 extend outwardly from 20 formation 52 to flange 48 and upwardly to wall 44. A recess 62 is let into wall 44 from the upper surface, and in use of cap 42 receives nut 12 so that surface 13 of plate 7 can abut surface 46. A second recess 64 extends radially inwardly from flange 48 and terminates in a surface 66 that is coplanar with an outer surface 68 of one 25 face 70 of formation 52. A chevron-shaped slot opening 74 is formed in wall 44 and has a shoulder 72 extending along its concave side. To provide support means 40, tube 20 is first driven into ground mass 5 leaving a short part of tube 20 protruding above ground surface 4. Cap 42 is 30 then placed on top of tube 20, with triangular tube 20 entering the interior of formation 52, sliding over surface 54 thereof until its end face 26 abuts shoulder 72 and lower surface 50 of wall 44. Next, cap 42 is secured to tube 20, by positioning a self-drilling, self tapping screw fastener (not shown) in recess 64 and driving it through surface 14 66 into adjacent part 78 of tube 20 and adjacent part 80 of formation 56 (Figure 15). This completes the provision of support means 40. With tube 20 secured in the interior space of formation 52, chevron sectioned lower part 8 can be passed through slot 74 between shoulder 72 5 and the exterior of formation 56. Slot 74 is so sized that even when there is no lower part 8 therein, there is only limited room for debris (not shown) to fall into the interior of tube 20, compared to the situation if tune 20 were not fitted with cap 42. Lower part is slid downwardly, being received neatly within the interior space 21 of tube 20, until lower surface 13 of plate 7 of ground anchor 10 6 abuts upper surface 46 of cap 42. Tube 20 can conveniently be an aluminium extrusion, or may be formed in other ways or materials if required. For example, tube 20 could be a hot formed steel tube, or formed into its triangular section shape from steel strip. 15 Although Figure 10 shows plate 7 of ground anchor 6 being supported by the completed support means 40 somewhat higher than ground surface 4, it is possible to lower it by making a slight depression in ground surface 4 before fixing tube 20 in place. Grass on horse racing tracks is commonly quite long (eg up to about 15cm) and in these circumstances having plate 7 slightly 20 above a flat ground surface 4 is provisionally thought likely to be quite acceptable in practice. There is limited scope for debris to enter tube 20 when cap 42 is used in normal practice, so that means to specifically prevent such ingress of debris is thought unnecessary. However, a further cap (not shown) could be 25 provided if required, for example being close-fitting over top surface 46 and around flange 48. The caps 42 once installed would be quite visible and so easy to find and to use to provide a datum for measurements when placing barrier fence 1 in a new position. They would also provide less of a trip hazard than a set of tube 20 tops without such caps. 30 While the above description has covered specifically barrier fences having uprights with ground anchors secured at their lower end, it will be apparent that movable fences (not shown) could be provided in which uprights are not secured to separate ground anchors but are instead adapted to themselves either be driven into a ground mass or received in support means 15 generally on the principles described for the ground anchor support means described above. Many variations, within the scope of the innovation, will in the light of this disclosure suggest themselves to persons skilled in the art. One 5 possibility, for example, is to provide an alternative (not shown) to the tube 20 shown in Figure 6, namely a tube of similar or the same cross-section, but with a closure at its lower end, preferably shaped for ease of driving into ground mass 5. A driving tool equivalent to tool 22 could then have a lower section of similar or the same cross-section to that of part 24 of tool 22, but 10 without the chisel-shaped lower end 27.