827,969. Mono-rail switch tongues. ALWEGFORSCHUNG G.m.b.H. March 5, 1956 [March 11, 1955], No. 6837/56. Class 104 (2). In a switch for a beam-shaped mono-rail track in which the track is straddled by a vehicle provided with a supporting wheel running on the top of the beam and with side wheels bearing on tracks on the beam side faces the switch is flexible or is constructed so that parts thereof are relatively movable when the switch is moved from one operative position to another operative position. As shown in Fig. 1 the ends of the reinforced concrete track 40 terminate on a reinforced concrete bed-plate 41 to which bedplate 41 are secured a number of guide tracks 42 on which are moved supporting shoes 43 of articulated movable switch sections 44. Movement of the switch is effected by a rack-andpinion 45, 46. Stops 47 determine the limit of movement of the switch and locking means 471 hold the track shoes 43 in their two end positions. The movable switch, Figs. 3 and 4, consists of a pair of parallel plates 48 welded to H-section girders 49. Cantilever brackets 51, carried at the upper end of the plate 48, support a running track 58 provided with an under-face plate 59 freely resting on the brackets 51. The track 58 is held in position by spigots 60 engaging sockets formed in the plate 59 and fixed to the upper H-section girder by square shanks 61. Flat sheet-metal arms 52, 53 extend outwardly from the plates 48 and are interconnected by ties 54 on which box section side tracks 55 are mounted by hook-shaped members 56 so that when the switch is bent to the position shown in Fig. 1 the side track 55 can be displaced longitudinally in relation to the supporting members 52, 53, 54. Gusset plates 62 at the foot of member 48 are attached to a beam 63 provided with a roller 64 which runs on a traversing rail 65. If the switch is entirely of reinforced concrete the beam 63, Fig. 5 (not shown), is located directly beneath the pivot axis which comprises a pivot pin provided with a bearing-plate supported on a sleeve collar secured to the beam 63. The side tracks 55, Fig. 7, may be deformed by eccentric discs 71 mounted on an articulated shaft extending longitudinally of the switch body. On one side of the switch the side tracks 55 are connected to plate 73 provided with circular bores 74 inside which the eccentric discs 71 are rotated. The side tracks on the opposite side of the switch are articulated to the plate 73 by rods 75. In a modification, Fig. 9 (not shown), the side tracks are deflected by a number of vertically arranged cylinders disposed in cavities in the side of a concrete switch. A suitable pressure exerted on a piston against a spring moves the side track outwardly through the intermediary of a toggle lever device which is moved past a dead-centre position. In the modification shown in Fig. 10, two rigid articulated track sections are pivotally connected to the fixed track 40. The running surface has one straight edge 85 and one curved edge 84 to form a continuous arc when the switch is in the deflected position. The side tracks, however, are straight on one side 86 and curved inwardly on the other side 87. In the arrangement shown in Fig. 14, the side tracks 91, 92 are deformed by a shaft 96 carrying a crank arm or eccentric 97 operating in a large circular bore 95. In a further embodiment, Fig. 15 (not shown), segmental side track sections are moved vertically into or out of the operative position by racks-and-pinions. In a further arrangement, Fig. 16 (not shown), the upper side tracks are deformed by rack-and-pinion to the necessary curvature whilst the lower side tracks comprise segmental sections which can be pivoted into or out of the operative position about hinges. In the steel lattice work switch construction shown in Figs. 17, 18 and 22, the switch section is swung about an axis 106 and is mounted on rollers 107. The vehicle is supported by a double-flanged wheel (Fig. 22) which runs on a rail 104 on the fixed track, but when passing over the switch section runs over the rail 114 for straight-through travel and over a rail 115 for branch line travel. The side guide tracks on the main monorail section are indicated by reference numeral 105. When the vehicle passes over the switch section the doubleflanged wheel runs over a rail 114 for straightthrough travel and over a rail 115 for branch line travel. Frogs 116 and check-rails 117 and 118 are provided at cross-over points of the rails 114, 115 at each end of the switch. The switch has straight side guide tracks 120 on one side and curved side guide tracks 122 on the other side and carries vertically movable side track segments 112, 113 at each end and 110 and 111 at the centre, so that when the switch is in the straight-through travel position (Figs. 18, 22) the end segments 112 and the centre segment 111 are moved into the operative position to provide straight side tracks; and when the switch is moved to the branch line position the end segments 113 and the centre segment 110 are moved into the operative position to form curved side guide tracks. The movable side track segments 110, 111, 112, and 113 are vertically displaced on slide-ways 129 in opposite directions by means of ropes 130 and pulleys. In a flexible switch shown in Fig. 23 the switch comprises six metal sheets 131 held in spaced relation by sleeves and transverse bolts passing through slots in the plates. Box sections on, or C-shaped members 132 welded to, the sheets 131 having their lower ends supported by ribs 133, 134 secured to plates 131, form the supporting surface. The lower longitudinally movable side tracks 135 are suspended on the ribs 134. Bevelled extensions 136 on the ribs 134 attached to the frame 137 wedge under surfaces 138 to lock the switch in either of its end positions. In a further arrangement shown in Fig. 24 the plates 131 are rigidly connected to H-section girders 139 and transverse plates 140 riveted or welded to the outer plates 131 having castellated upper edges which are embraced by channel-sections 141 forming the supporting track. The upper longitudinallymovable side tracks 142 are suspended over the outer castellations and are held in position by pins 144 and the lower longitudinally movable side tracks are suspended in notches in the plates 140 and are held in position by angles 145 or pins 144. The surface of the member 141 is slightly higher than the top edge of the side tracks 142. The running surface, Fig. 25 (not shown), can be formed by metal strips placed across plates to form a base for boxes formed by welding zig-zag plates to the strips and filling the boxes with a suitable surfacing material such as asphalt emulsion or a bitumen cement. In a further arrangement, Fig. 26 (not shown), a further modification of the running surface is provided in which transverse dovetailed channels engage dovetailed members welded to strips and held in position by the upper portions of the side tracks. Fig. 27 shows a further form of switch construction in which the switch is capable of torsional as well as flexible deformation. The switch comprises a box-shaped member 150 to which is welded a metal rib 151 terminating in an upper plate 152. Transverse plates 153 are secured to the plates 151 at intervals therealong and some merge into a supporting pedestal with edges reinforced with angles 155. The upper plate 152 is connected to a cross-beam 156 which carries a central plate 157 formed with grooves and a support 158 at each end with the interposition of angles 160 for box section vehicle supporting tracks 159, the upper and side faces of which are faced with a non- metallic surfacing material 161. The tracks 159 each consist of inwardly-facing channel members joined by plates 162 connected to the plates 153 by vertical ties 163 running parallel with ties 164 carrying the lower longitudinallymovable side tracks 165 and supported at their upper end from the crossbeam 156 and at their lower end by crossbeam 166. The pedestal 154 is arcuate shape so that when the switch has been deflected to a branch line position the switch can be twisted by gears 168 driven from a shaft 169 through a chain drive 170 operating in conjunction with a curved rack 171. Locking- pins 172 retain the pedestals in the tilted or upright position. In yet a further arrangement, Figs. 28, 29 (not shown), a box section track reinforced with a rib has angle-brackets which form the running and side tracks and are cast integrally with the box section by means of brackets spaced apart so as to allow the track to be flexed transversely. The switch section may comprise a number of box sections joined by bolts passing through webs in internal flanges. The switch may also comprise three box section members arranged side-by-side and joined by transverse bolts passing through elongated holes therein, Fig. 30 (not shown). In a further arrangement the side tracks are formed by a number of articulate bars hinged together so as to form a polygonal profile on the inside of the track when the switch is deflected, Figs. 31 to 37 (not shown). In a further arrangement, Figs. 38, 39 (not shown), for a switch of small radius of curvature a number of rigid units are articulated together and the limit of deflection of each section is determined by a gap between the abutting ends of each section on each side of the hinges at the articulation point.