Delighted to hear of Hornby's J50/4. My two K's kits with scratchbuilt chassis date from 1974 - 40 years old!! One is now struggling, the other running beautifully. I'm sure I'll have to add weight to it though for the Copley Hill ski slope!
I started kit building in 1976 with 2 K's J50's and built my own chassis - they are still the two sweetest slow running engines on my Copley Hill layout (gradually being built). My kit building is not hot (just ask Tony W) but what immense satisfaction!Dave W
I much prefer the prototype - when modelling it is almost like trying to recreate images in your mind blended with prototype photos and plans of the time e.g. 1959-1961.