Originally Posted by Ted Hikel:
Those curve requirements tend to be conservative and I wouldn't be surprised to hear that the heavy mike can handle less than O-54.
I have found that to be true as well. I have been able to get an MTH premier PRR J-1 and T-1 to negotiate O-48. They are both listed as O-72. Many of Lionel's engines listed for O-54 will easily do O-48.