I have two R859 which whist running very freely have extremely poor traction. Compared with the fine results given by the 4F and 2P, indeed, even the Dean goods, I decided to modify the tender unit to include 4 tyred wheels and place pickups on the insulated driving wheels of the loco. There are two convenient holes in the chassis block which can carry the mounting plate for the P.U.'s The results have been pleasing and yet still not as effective as the other 4 wheel drives. Has anyone tried this with better results?