Was reading through a 1985 modelling book which is a reprint of 1925 Model Making by R.F.Yates and came across plans for modelling a gyro stabilised mono-rail which had pictures of a model balanced on a taught wire, as if by magic. The design had a single vertical axis gyro doing the job, but when I tried to look up what this model was based on I came across the British Brennan Gyro and found that had two horizontal gyros with opposite rotation, and he made a 5 foot prototype which would carry a man and amazed people when shown. They were even more amazed when he produced the full 22 ton prototype in 1909, and he exhibited it at White City in 1910. It would take about 40 people at a time round the 1 mile track banking on the corners but standing perfectly upright when stationary, even as people clambered aboard. Thats the nearest thing to an engineering magic trick I can imagine, so I am wondering if anyone has made any of these models since that original 1925 book came out. There was also a gyro stabilised car created - a bit like a huge motorcycle except with a car body and you could move around from side to side without upsetting it and it would balance perfectly when stationary, although it had outriggers for when you wanted to power down the gyro.