WOW, that is an incredible line up of steam traction, both miniature and full size! The advantage in England are the short travel distances to a meet like this. I don't know of anything similar that happens in the US. I'd say most of steam traction in the US focuses on the full size engines at local threshing shows, (which are quite numerous).
Yes, it's very exciting to come across a 1/4 scale here and there at shows... Rollag, MN is probably the closest I have been to something like this, quite a few engines at their Miniatureland.