Hi Daniel,
Back in "the day" Lionel offered "Magna-Traction" on some of their engines, to help keep them more firmly down on the rails around those over tight turns, but even that certainly wouldn't have held any of their engines on the corners, and at the speeds, that your engine was flying around!?!?
The tender has replacement modern wheels, the locomotive has had it's original wheels reprofiled to suit modern track. But I still find it amazing than it manages to stay on the twelve inch radius curves.
Today we leave to exhibit at a garden railway show in the north of the country so I will try the model on the track of our Ffordd-y-Deryn layout and report results.
Take care Tony.