Let Wilbert explain for you: "I built Percy in 1949 (the year I wrote Troublesome Engines - the book in which Percy first appears) and I soldered him together out of brass and other parts cut and filed to shape. I wanted another engine - Thomas was then the only one I had - and I also wanted a model of Percy to help our then artist draw his pictures; but the artist did not pay much attention, so my Percy - the proper one - looks different from the Percy in the books. Stewart Reidpath made a chassis for me and fitted it with one of his motors, so Percy is sometimes as temperamental as Thomas and for the same reason. He will run and shunt beautifully for weeks on end and then suddenly and for no apparent reason, decide to be 'awkward'. This can be exasperating, especially at exhibitions. He did this at Nottingham Exhibition 1978 and the only thing to do then was to use my 'Spare Percy' which I had made for just such an emergency. To make 'Spare Percy' I cut out the boiler and side tanks from a Tri-ang 'Nellie' and filled the resulting space between the cab and smokebox with a section of saddle tank cut from an Airfix kit. The outside cylinders came from another Airfix kit and were cemented to 'Nellie's' metal frames with Evostick. I fitted scale size wheels in place of 'Neillie's' rather clumsy ones and filled up the body with plasticine. The good wheels and extra weight has made 'Spare Percy' into a smooth running engine almost as good as the real Percy in his best moments".
@Domix258 for some parts