How it works: Even on perfect track, it is necessary for the axles to be able to twist, relative to one another. The wheels have a conical tread so that as they run to one side or the other the rolling diameter will change and steer the wheelset back to the centre of the track. Â Furthermore if the track is laid to a cant* on the curves or there is any unevenness in the track, then the wheels will follow, twisting the pivot wire between the w-irons. The other two wires will then resist the twisting action so as to equalise the body movement between the 2 w-irons. This is different to a simply compensated wagon where the body moves entirely with the fixed axle. In terms of vertical movement, the only âspringâ is the flexing of the w-iron unit itself. This is comparatively rigid so that the ride height is constant and the weight of the wagon is not significantly important. But when one wheel of the wagon hits a bump, there is still a smoothing effect as the torsion springs take up the shock.
Couplings: Â The system has been developed with the use of 3-link and Alex Jackson couplings in mind. Â 3-link couplings may be fitted to the headstock (buffer beam). Â The suspension plates have a large tab at the outer end which forms a vertical upper limit to the coupling movement at that end and a mounting point for the coupling at the remote end. Â In addition there is provision for a guide loop on the inner side of the plate, against which the horizontal movement of the coupling may be adjusted.
Further details may be examined from the instruction which are downloadable from the tab below.
*cant is the raising of the outer rail on the outside of a curve. Â The maximum protoype rise is 6 inches, or 2mm in 4mm scale.
This may be introduced over a scale distance of 200-300mm, which for a long vehicle of say 20ft (80mm) wheelbase is quite some twist! Â
Also now available, are wheelbase jigs for spacings of 7ft to 22ft in increments of 3ins. Â
Instructions may be downloaded from here Suspension_Plates.pdf