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As part of the socially distanced challenge of the Scalefour Society I decided to have a go at making the unusual 3 bogie Totem wagon that was fitted with the Dean type bogie suspension. The work is detailed on the Society's forum.
Totem bogie
The challenge I envisaged was finding that the model would not work properly because of the difficulties in scaling down the dynamics of the coilspring suspension.
For anyone who has not come across this type of bogie one should note the following. The vehicle is supported by the cross beam, from there the load is transferred to the suspension bolts held up by the top bolster. The top bolster rests on springs between it and the bottom bolster that rests on supports on the bogie side frames. The channel section bolsters are free to slide up and down the guides. The holes in the bolsters and beams have enough clearance for the bolts to swing on the hemispherical washers so that the bogie can move relative to the body. The bogie cross braces only function to keep the sides the correct distance apart, they are thin enough to allow the sides to "rotate" relative to each other. Despite the design sometimes being referred to as "centreless" the bogie did have a central pivot pin, but this carried no weight.
The outcome was a wagon that runs very smoothly, even on rough track, provided that it is close to a straight line. Although the bogies do rotate, and the centre one can move sideways, I did not ensure there were enough clearances everywhere and on curves the bogies can hit the underframe resulting in derailments. Correcting this would entail making several new parts for the bogies so, following the prototype, I've decided it was not a good design: however I'm not going to rebuild it with just two more conventional bogies as the GWR did with theirs!