This model generally requires a 42″ minimum radius for satisfactory operation.
Extra pictures added 26 December 2019
Note the phosphor bronze wire centring spring fitted to the pilot truck.
Close up of rear truck showing the material removed from the sideframe flange (yellow arrow) to allow increased sideways displacement of the truck. This modification allows this loco to run round 48″ radius curves smoothly and consistently. Curving performance on 36″ radius curves is marginal, especially on hand laid track. No modifications to the truck bolster.