It's a lovely image, Mr Dodo. But alas, that train ain't going nowhere (even when new). There's an engineering mistake. You have a rod going from the piston to the 1st set driving wheels(call that the driving rod), then a 2nd rod (slave rod) going to the next set of wheels. (Not sure about the technical terms for these things, but I hope you get my drift.) Trouble is that they are separate. After less than one revolution, the two rods will collide and everything will shudder to a stop. Simple fix: connect the driving rod to the slave rod (offset outwards a bit) and all will work...:-) Cheers, Diolma