A very long time ago, some 10 years to be precise, I started a conversion of a Hornby West Country pacific to P4. At the time, I was trying to use the existing chassis and had modified the existing bogie and pony trucks. I was having all manner of problems with the slide bars though and despite trying everything I could think of just couldn’t get it to run properly. After a valiant effort I reached the point where I stopped and put it to one side for a proper think.
I decided to go down the