Something I forgot to mention about this chassis, but which came to mind while tinkering this evening, is that the centre axle is sprung. But there is practically no vertical movement as supplied. A slight deepening of the recess in which the sprung plunger locates; and on the keeper plate,cutting down the centre rib over the diameter of the plunger, and axle clearances in the sides, allows useful travel. If the model is made heavier, the spring can be stretched so that more load is placed on this wheelset. Definitely improves pick up reliability, always important with short wheelbase locos.