@Chrisjo, Thanks for thebinformation.
Wow plarail really loves the d51, after all, it's their country's famous engine, the master of the railway.
Train it, plane it, you name it!
I love the 'long' side rod versions on the earlier Plarail steamers even the Thomas ones like earlier versions of Gordon and Henry. They look and move a little more realistic than the modern, axle to axle types. That being said, I can see we they changed as the longer ones could easily come out of the front slide, get bent and possibly poke an eye out when out and the motor running. I imagine after all those years they changed them for safety and to last longer.