is joined to the second support post 44 by bolts 54 however it is a matter of course that the base plate 50 may be joined to the second support post 44 by any arbitrary joining method such as welding or the like the retaining plate 52 a extends in a downwardly inclined manner toward the side of the travel path 200 from a lower end of the base plate 50 stated otherwise the plane of the retaining plate 52 a is oriented in an upwardly inclined manner toward the side of the travel path 200 the retaining plate 52 b extends in an upwardly inclined manner toward the side of the travel path 200 from an upper end of the base plate 50 stated otherwise the plane of the retaining plate 52 b is oriented in a downwardly inclined manner toward the side of the travel path 200 as shown in fig5 the downwardly positioned support member 48 a serves to support the power line 26 n and includes an insulator 56 disposed on the retaining plate 52 a a power line platform 58 attached to the insulator 56 and a clamp 60 that fixes the power line 26 n to the power line platform 58 the insulator 56 comprises an insulating member 64 on which a threaded.